MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Physica Medica' source. Mon, 06 Feb 2012 20:25:00 +0100 http://www.medworm.com/index.php?rid=5638520&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22281096%26dopt%3DAbstract Authors: Monti AF, Berlusconi C, Gelosa S Abstract Intensity Modulated Radiation Therapy (IMRT) is a complex treatment modality that requires pre-treatment patient-specific quality control (QC) in order to assess a correct treatment delivery. The aim of this work is to investigate pre-treatment patient-specific per-field QCs performed with an on-board EPID at the gantry angle of 0° and at the treatment ones, and to asses if measurements executed at 0° are able to guarantee a correct treatment. Ten patients with prostate cancer were evaluated. Two "verification" plans were created for each patient in order to calculate the dose at the EPID surface: one with all fields positioned at 0° and one with all fields at the actual treatment angles. EPID's mechanical shifts due to gravity ... Physica Medica journals http://www.medworm.com/rss/comments.php?id=5638520 Wed, 25 Jan 2012 05:00:00 +0100 5638520 http://www.medworm.com/index.php?rid=5638521&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22277185%26dopt%3DAbstract Authors: Erazo F, Lallena AM Abstract The beam quality correction factor [Formula: see text] and the perturbation factor p(Q), commonly considered in dosimetry with ionization chambers, were calculated for the NE2571 and the Standard Imaging A19 and A12S chambers, using the Monte Carlo simulation code PENELOPE. For the NE2571 chamber, the values of [Formula: see text] obtained are in very good agreement with those found in previous works by Wulff et al. and Muir and Rogers with the code EGSnrc and also with the experimental results summarized in the NCS code of practice. For p(Q), a difference of ∼0.4% has been found between our results and those obtained with EGSnrc for (60)Co and this difference increases slightly with TPR(10)(20) values. These factors have been calculated als... Physica Medica journals http://www.medworm.com/rss/comments.php?id=5638521 Mon, 23 Jan 2012 05:00:00 +0100 5638521 http://www.medworm.com/index.php?rid=5577906&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22221470%26dopt%3DAbstract CONCLUSIONS: Application of the blind inverse optimization (BIO) algorithm led to clinically best dose parameters for PTV and the rectum. Use of geometrical optimization (GO) led to smaller doses in the urethra, which was however associated with a certain dose decrease also in PTV. PMID: 22221470 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=5577906 Tue, 03 Jan 2012 05:00:00 +0100 5577906 http://www.medworm.com/index.php?rid=5577907&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22217444%26dopt%3DAbstract Authors: Miéville FA, Gudinchet F, Brunelle F, Bochud FO, Verdun FR Abstract This paper characterizes and evaluates the potential of three commercial CT iterative reconstruction methods (ASIR™, VEO™ and iDose(4 ()™())) for dose reduction and image quality improvement. We measured CT number accuracy, standard deviation (SD), noise power spectrum (NPS) and modulation transfer function (MTF) metrics on Catphan phantom images while five human observers performed four-alternative forced-choice (4AFC) experiments to assess the detectability of low- and high-contrast objects embedded in two pediatric phantoms. Results show that 40% and 100% ASIR as well as iDose(4) levels 3 and 6 do not affect CT number and strongly decrease image noise with relative SD constant in a large range of... Physica Medica journals http://www.medworm.com/rss/comments.php?id=5577907 Mon, 02 Jan 2012 05:00:00 +0100 5577907 http://www.medworm.com/index.php?rid=5559697&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22202190%26dopt%3DAbstract Authors: Smits M, Visch-Brink EG, van de Sandt-Koenderman ME, van der Lugt A Abstract Smits M, Visch-Brink EG, van de Sandt-Koenderman ME, van der Lugt A. Advanced magnetic resonance neuroimaging of language function recovery after aphasic stroke: a technical review. Arch Phys Med Rehabil 2012;93(1 Suppl 1):S4-14. Two advanced magnetic resonance neuroimaging techniques, functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI), have recently made their way into clinically oriented research and hold great promise to study the brain's adaptive changes of function and structure after aphasic stroke, respectively. Such functional and structural neuroplasticity is thought to underlie the recovery of language function, occurring spontaneously and/or in the context o... Physica Medica journals http://www.medworm.com/rss/comments.php?id=5559697 Sun, 01 Jan 2012 05:00:00 +0100 5559697 http://www.medworm.com/index.php?rid=5559698&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22209626%26dopt%3DAbstract Authors: Mikołajczyk K, Piotrowski T Abstract The aim of this study was to design a cylindrical stepwedge phantom and an appropriate treatment procedure, based on which parameters of tomotherapy machine and generated beam of radiation will be defined. The accuracy of parameter determination, which can be defined with the aid of the measurement system, was also evaluated. The cylindrical phantom that we developed and manufactured (stepwedge phantom) consists of four cylinders with different diameters made of polycaprolactam-PA-6, i.e. material with high mechanical strength, low water absorption (making measurements repeatable) and a density comparable to that of human soft tissues. The appropriate treatment procedure is carried out in a dynamic mode, which is focused on specific pr... Physica Medica journals http://www.medworm.com/rss/comments.php?id=5559698 Fri, 30 Dec 2011 05:00:00 +0100 5559698 http://www.medworm.com/index.php?rid=5559699&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22209110%26dopt%3DAbstract Authors: Seregni M, Pella A, Riboldi M, Orecchia R, Cerveri P, Baroni G Abstract The purpose of this study was to develop and assess the performance of a tumor tracking method designed for application in radiation therapy. This motion compensation strategy is currently applied clinically only in conventional photon radiotherapy but not in particle therapy, as greater accuracy in dose delivery is required. We proposed a tracking method that exploits artificial neural networks to estimate the internal tumor trajectory as a function of external surrogate signals. The developed algorithm was tested by means of a retrospective clinical data analysis in 20 patients, who were treated with state of the art infra-red motion tracking for photon radiotherapy, which is used as a benchmark. Int... Physica Medica journals http://www.medworm.com/rss/comments.php?id=5559699 Thu, 29 Dec 2011 05:00:00 +0100 5559699 http://www.medworm.com/index.php?rid=5559700&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22206908%26dopt%3DAbstract The objective of this study is to develop an automatic clip localization procedure for breast cancer patient setup based on Digital Tomosynthesis (DTS) and to characterize its performance with respect to the overall registration accuracy and robustness. The study was performed under an IRB-approved protocol for 12 breast cancer patients with surgical clips implanted around the tumor cavity. The registration of DTS images to planning CTs was performed using an automatic algorithm developed to overcome specific challenges of localization and registration of clips in the breast setup images. The automatic method consisted of auto-segmentation (intensity-based thresholding with a priori knowledge about clip size and location to distinguish clips from bony features) and auto-registration of the... Physica Medica journals http://www.medworm.com/rss/comments.php?id=5559700 Tue, 27 Dec 2011 05:00:00 +0100 5559700 http://www.medworm.com/index.php?rid=5548624&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22200603%26dopt%3DAbstract Authors: Hanus J, Nosek T, Zahora J, Bezrouk A, Masin V Abstract We designed and evaluated an innovative computer-aided-learning environment based on the on-line integration of computer controlled medical diagnostic devices and a medical information system for use in the preclinical medical physics education of medical students. Our learning system simulates the actual clinical environment in a hospital or primary care unit. It uses a commercial medical information system for on-line storage and processing of clinical type data acquired during physics laboratory classes. Every student adopts two roles, the role of 'patient' and the role of 'physician'. As a 'physician' the student operates the medical devices to clinically assess 'patient' colleagues and records all results in an e... Physica Medica journals http://www.medworm.com/rss/comments.php?id=5548624 Sat, 24 Dec 2011 05:00:00 +0100 5548624 http://www.medworm.com/index.php?rid=5533020&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22182517%26dopt%3DAbstract CONCLUSIONS: From the viewpoint of ROC analysis-based CNR for lesion detection, CNR-based AEC potentially provide image quality advantages for clinical implementation. PMID: 22182517 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=5533020 Sat, 17 Dec 2011 05:00:00 +0100 5533020 http://www.medworm.com/index.php?rid=5533021&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22177584%26dopt%3DAbstract In conclusion 10 mg/kg melatonin is likely to be a threshold concentration for significant protection against lower dose of 2 Gy gamma irradiation compared to higher dose of 8 Gy. Therefore, it seems that radio-protective effects of melatonin are dose-dependent. PMID: 22177584 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=5533021 Thu, 15 Dec 2011 05:00:00 +0100 5533021 http://www.medworm.com/index.php?rid=5533022&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22169350%26dopt%3DAbstract CONCLUSIONS: Radiation leakage of up to 170% of the prescribed dose has been found at the back surface of these applicators. Although this side is not usually directed to the patient, in some applications such as the treatment of a lesion on the nose, special care must be taken to avoid unexpected and unnecessary irradiation of the eyes. A possible solution could be to add additional shielding to the applicator in order to reduce this leakage or to put some shielding to protect the eyes. Additionally, a new concept design of the Valencia applicators using more shielding material in the applicator backside is proposed. PMID: 22169350 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=5533022 Thu, 08 Dec 2011 05:00:00 +0100 5533022 http://www.medworm.com/index.php?rid=5533026&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22138139%26dopt%3DAbstract Authors: Corazza I, Rossi PL, Feliciani G, Pisani L, Zannoli S, Zannoli R Abstract The aim of this paper is to clarify some physical-mechanical aspects involved in the carbon dioxide angiography procedure (CO(2) angiography), with a particular attention to a possible damage of the vascular wall. CO(2) angiography is widely used on patients with iodine intolerance. The injection of a gaseous element, in most cases manually performed, requires a long training period. Automatic systems allow better control of the injection and the study of the mechanical behaviour of the gas. CO(2) injections have been studied by using manual and automatic systems. Pressures, flows and jet shapes have been monitored by using a cardiovascular mock. Photographic images of liquid and gaseous jet have bee... Physica Medica journals http://www.medworm.com/rss/comments.php?id=5533026 Fri, 02 Dec 2011 05:00:00 +0100 5533026 http://www.medworm.com/index.php?rid=5533025&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22149841%26dopt%3DAbstract Conclusions: A number of general conclusions are evident: (1) small field OR(det) are very sensitive to the simulated source parameters, and therefore, rigorous Monte Carlo linac model commissioning, with respect to measurement, must be pursued prior to use, (2) backscattered dose to the monitor chamber should be included in simulated OR(det) calculations, (3) the corrections required for diode detectors are design dependent and therefore detailed detector modeling is required, and (4) the reported detector specific correction factors may be applied to experimental small field OR(det) consistent with those presented here. PMID: 22149841 [PubMed - in process] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=5533025 Thu, 01 Dec 2011 05:00:00 +0100 5533025 http://www.medworm.com/index.php?rid=5533024&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22149860%26dopt%3DAbstract Comment on "In-patient to isocenter KERMA ratios in CT" [Med. Phys. 38, 5362-5369 (2011)]. Med Phys. 2011 Dec;38(12):6787 Authors: Li X, Zhang D, Liu B PMID: 22149860 [PubMed - in process] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=5533024 Thu, 01 Dec 2011 05:00:00 +0100 5533024 http://www.medworm.com/index.php?rid=5533023&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22149861%26dopt%3DAbstract Erratum: "Secondary neutron spectra from modern Varian, Siemens, and Elekta linacs with multileaf collimators" [Med. Phys. 36(9), 4027-4038 (2009)]. Med Phys. 2011 Dec;38(12):6789 Authors: Howell RM, Kry SF, Burgett E, Hertel NE, Followill D PMID: 22149861 [PubMed - in process] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=5533023 Thu, 01 Dec 2011 05:00:00 +0100 5533023 http://www.medworm.com/index.php?rid=5455169&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22119271%26dopt%3DAbstract CONCLUSION: The NTCP models of RIF, incorporating the effects of fractionation, volume effect, and latency of toxicity look promising to model PBI. Clinical validation from a prospective PBI treatment study is under development and will help test this preliminary result. PMID: 22119271 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=5455169 Fri, 25 Nov 2011 05:00:00 +0100 5455169 http://www.medworm.com/index.php?rid=5455168&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22119272%26dopt%3DAbstract Authors: Schröder L Abstract NMR studies with hyperpolarized xenon as functionalized sensor or contrast agent recently made notable progress in developing a new approach for detecting molecular markers and parameters of biomedical interest. Combining spin polarization enhancement with novel indirect detection schemes easily enables a 10(7)-fold signal gain, thus having promising potential to solve the NMR sensitivity problem in many applications. Though an inert element, (129)Xe has exquisite NMR properties to sense molecular environments. This review summarizes recent developments in the production of hyperpolarized xenon and the design and detection schemes of xenon biosensors. PMID: 22119272 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=5455168 Fri, 25 Nov 2011 05:00:00 +0100 5455168 http://www.medworm.com/index.php?rid=5418849&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22079402%26dopt%3DAbstract CONCLUSION: The adaptive re-planning strategy based on the first week CBCT dataset significantly reduces the doses and NTCP to OARs. PMID: 22079402 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=5418849 Thu, 10 Nov 2011 05:00:00 +0100 5418849 http://www.medworm.com/index.php?rid=5418850&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22071169%26dopt%3DAbstract Authors: Siggel M, Ziegenhein P, Nill S, Oelfke U Abstract Pencil beam algorithms are still considered as standard photon dose calculation methods in Radiotherapy treatment planning for many clinical applications. Despite their established role in radiotherapy planning their performance and clinical applicability has to be continuously adapted to evolving complex treatment techniques such as adaptive radiation therapy (ART). We herewith report on a new highly efficient version of a well-established pencil beam convolution algorithm which relies purely on measured input data. A method was developed that improves raytracing efficiency by exploiting the capability of modern CPU architecture for a runtime reduction. Since most of the current desktop computers provide more than one calc... Physica Medica journals http://www.medworm.com/rss/comments.php?id=5418850 Mon, 07 Nov 2011 05:00:00 +0100 5418850 http://www.medworm.com/index.php?rid=5418851&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22061446%26dopt%3DAbstract In conclusion, (SURE)Exposure 3D resulted in more uniform image quality at a lower dose. Volumetric TCM shows improved results over longitudinal TCM. PMID: 22061446 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=5418851 Sat, 05 Nov 2011 04:00:00 +0100 5418851 http://www.medworm.com/index.php?rid=5418852&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22056674%26dopt%3DAbstract CONCLUSIONS: A general formula for exact geometric matching in radiotherapy of the breast and supraclavicular fossa is presented. The method does not require additional shielding to eliminate divergence other than the four independent jaws. The result is simple to implement in modern delivery facilities. PMID: 22056674 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=5418852 Fri, 04 Nov 2011 04:00:00 +0100 5418852 http://www.medworm.com/index.php?rid=5379268&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22047359%26dopt%3DAbstract Conclusions: The thread effect can be well explained by the proposed model. Optimization can largely reduce the thread effect. However, an optimal pitch reduces the ripple much easier especially when optimization is limited by many constraints. The optimal pitches predicted by the proposed model could be used as a reference for pitch selection regardless the tumor is at large or small off-axis distance. PMID: 22047359 [PubMed - in process] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=5379268 Tue, 01 Nov 2011 04:00:00 +0100 5379268 http://www.medworm.com/index.php?rid=5379267&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22047366%26dopt%3DAbstract Conclusions: Following the TG-148 report, beam output measurements in water at the reference depth using a local protocol, as developed at different centers, was verified. The measurements were found in good agreement with alanine∕EPR dosimetry. The presented methodology may provide a good concept for reference dosimetry. PMID: 22047366 [PubMed - in process] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=5379267 Tue, 01 Nov 2011 04:00:00 +0100 5379267 http://www.medworm.com/index.php?rid=5379266&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22051017%26dopt%3DAbstract Authors: Otto KM, Ehricke HH, Kumar V, Klose U Abstract The advent of high angular resolution diffusion imaging (HARDI) has opened up new perspectives for the delineation of crossing and branching fiber pathways. However, image acquisition under clinical conditions with limited measurement time faces the problem of poor spatial and angular resolution and the technique's high susceptibility to noise. In this paper we present a straightforward spatial filter for ODF fields that uses the data-inherent structural information around a voxel as part of a directionally selective method for angular smoothing and radial regularization (ASRR). Especially in regions where fibers cross (multimodal voxels), the method allows us to reduce noise, improve the accuracy of ODF diffusion peaks, and s... Physica Medica journals http://www.medworm.com/rss/comments.php?id=5379266 Tue, 01 Nov 2011 04:00:00 +0100 5379266 http://www.medworm.com/index.php?rid=5360871&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22027546%26dopt%3DAbstract Authors: Mady MM, Fathy MM, Youssef T, Khalil WM Abstract Gold nanoparticles were prepared and loaded into the bilayer of dipalmitoylphosphatidylcholine (DPPC) liposomes, named as gold-loaded liposomes. Biophysical characterization of gold-loaded liposomes was studied by transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy as well as turbidity and rheological measurements. FTIR measurements showed that gold nanoparticles made significant changes in the frequency of the CH(2) stretching bands, revealing that gold nanoparticles increased the number of gauche conformers and create a conformational change within the acyl chains of phospholipids. The transmission electron micrographs (TEM) revealed that gold nanoparticles were loaded in the liposomal... Physica Medica journals http://www.medworm.com/rss/comments.php?id=5360871 Sun, 23 Oct 2011 04:00:00 +0100 5360871 http://www.medworm.com/index.php?rid=5325636&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22001564%26dopt%3DAbstract The objective of this study was to develop phantoms of liver and kidney tissue to experimentally characterise interstitial microwave antennas in reference conditions. Phantom properties depend on the simulated target tissue (liver or kidney) and the considered frequency (2.45 GHz in this work), addressing the need for a transparent liquid to easily control the positioning of the probe with respect to the antenna under test. An experimental set-up was also developed and used to characterise microwave ablation antenna performances. Finally, a comparison between measurements and numerical simulations was performed for the cross-validation of the experimental set-up and the numerical model. The obtained results highlight the fundamental role played by dielectric simulators in the development ... Physica Medica journals http://www.medworm.com/rss/comments.php?id=5325636 Fri, 14 Oct 2011 04:00:00 +0100 5325636 http://www.medworm.com/index.php?rid=5325639&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21983525%26dopt%3DAbstract Authors: Bahadori AA, Johnson P, Jokisch DW, Eckerman KF, Bolch WE Abstract Spongiosa in the adult human skeleton consists of three tissues-active marrow (AM), inactive marrow (IM) and trabecularized mineral bone (TB). AM is considered to be the target tissue for assessment of both long-term leukemia risk and acute marrow toxicity following radiation exposure. The total shallow marrow (TM(50)), defined as all tissues lying within the first 50 µm of the bone surfaces, is considered to be the radiation target tissue of relevance for radiogenic bone cancer induction. For irradiation by sources external to the body, kerma to homogeneous spongiosa has been used as a surrogate for absorbed dose to both of these tissues, as direct dose calculations are not possible using computational ph... Physica Medica journals http://www.medworm.com/rss/comments.php?id=5325639 Fri, 07 Oct 2011 04:00:00 +0100 5325639 http://www.medworm.com/index.php?rid=5325638&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21992372%26dopt%3DAbstract Conclusions: Both careful dosimetry and strict protocols for handling the TLDs are required to reach solid experimental data on relative detector response. This work confirms older findings that an over-response relative to (60)Co exists for photon energies below 200-300 keV. Comparison with the results from the literature indicates that using similar protocols for annealing and read-out, dosimeters of different makes (TLD-100, MTS-N) differ in relative detector response. Though universality of the results has not been proven and further investigation is needed, it is anticipated that with the use of strict protocols for annealing and read-out, it will be possible to determine correction factors that can be used to reduce uncertainties in dose measurements around brachytherapy sources at p... Physica Medica journals http://www.medworm.com/rss/comments.php?id=5325638 Sat, 01 Oct 2011 04:00:00 +0100 5325638 http://www.medworm.com/index.php?rid=5325637&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21992397%26dopt%3DAbstract Erratum: "A general framework and review of scatter correction methods in x-ray cone beam CT. Part 1: Scatter Compensation Approaches" [Med. Phys. 38(7), 4296-4311 (2011)]. Med Phys. 2011 Oct;38(10):5830 Authors: Rührnschopf EP, Klingenbeck K PMID: 21992397 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=5325637 Sat, 01 Oct 2011 04:00:00 +0100 5325637 http://www.medworm.com/index.php?rid=5246125&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21925912%26dopt%3DAbstract This article describes and particularly explains a new phenomenon of persistent microbicidal effect of water previously exposed to the low-temperature plasma, which cannot be attributed to the acidification only. The direct microbicidal action of plasma is well documented, being mediated by number of reactive particles with a short lifetime. However, we observed the microbicidal effect also in exposed water stored for a month, where it must be mediated by stable particles. In water and in phosphate-buffered saline, the formation of NO(x) and corresponding acids, H(2)O(2) and O(3) was confirmed after exposition to the low-temperature plasma generated in air by DC negative glow corona and positive streamer discharge. The time course of acidification, H(2)O(2) and O(3) formation were deremine... Physica Medica journals http://www.medworm.com/rss/comments.php?id=5246125 Sat, 17 Sep 2011 04:00:00 +0100 5246125 http://www.medworm.com/index.php?rid=5218400&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21907604%26dopt%3DAbstract Authors: Webb S Abstract During the delivery of intensity-modulated radiation therapy (IMRT) by the multileaf collimator (MLC) step-and-shoot technique, it is required to sequence the two-dimensional intensity-modulated beams (2D IMBs) into a series of components that can be shaped with the MLC. In this paper it is shown that the use of an MLC that has four banks of leaves (in two orthogonal pairs) instead of two banks only is advantageous for this purpose. PMID: 21907604 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=5218400 Thu, 08 Sep 2011 04:00:00 +0100 5218400 http://www.medworm.com/index.php?rid=5141182&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21820928%26dopt%3DAbstract Authors: Lohrasebi A, Mohamadi S, Fadaie S, Rafii-Tabar H Abstract We model the dynamics of the F(0) component of the F(0)F(1)-ATPase mitochondrion-based nano-motor operating in a stochastically-fluctuating medium that represents the intracellular environment. The stochastic dynamics are modeled via Langevin equation of motion wherein fluctuations are treated as white noise. We have investigated the influence of an applied alternating electric field on the rotary motion of the F(0) rotor in such an environment. The exposure to the field induces a temperature rise in the mitochondrion's membrane, within which the F(0) is embedded. The external field also induces an electric potential that promotes a change in the mitochondrion's transmembrane potential (TMP). Both the induced temper... Physica Medica journals http://www.medworm.com/rss/comments.php?id=5141182 Wed, 03 Aug 2011 23:00:00 +0100 5141182 http://www.medworm.com/index.php?rid=5097500&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21807542%26dopt%3DAbstract In conclusion, the devised MC simulation program can be a robust tool to optimize protocols and estimate patient doses for CBCT units in dental, oral and maxillofacial radiology. PMID: 21807542 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=5097500 Fri, 29 Jul 2011 23:00:00 +0100 5097500 http://www.medworm.com/index.php?rid=5097511&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21803627%26dopt%3DAbstract Authors: Semwal MK, Singh S, Sarin A, Bhatnagar S, Pathak HC X-knife and gamma knife techniques are well-established for cranial stereotactic radiosurgery (SRS). Due to differences in their radiation delivery methods, some of the dosimetric parameters of these two techniques differ which may have clinical significance. There are many dosimetric studies comparing linear accelerator based techniques such as X-knife with gamma knife but generally from different institutions. We carried out a retrospective comparative study of the dosimetric parameters of the SRS treatments performed at our centre with X-knife (circular cones) and gamma knife. Our results indicate that the dose conformity and dose fall-off in the vicinity of the target volumes were better for patients treated with gamma kn... Physica Medica journals http://www.medworm.com/rss/comments.php?id=5097511 Thu, 28 Jul 2011 23:00:00 +0100 5097511 http://www.medworm.com/index.php?rid=5097559&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21795090%26dopt%3DAbstract CONCLUSIONS: In conclusion, a common policy is followed in general, on topics concerning education and training as well as the practice of the medical physicist profession, notwithstanding the presence of a few differences. PMID: 21795090 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=5097559 Sun, 24 Jul 2011 23:00:00 +0100 5097559 http://www.medworm.com/index.php?rid=5097592&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21784685%26dopt%3DAbstract CONCLUSIONS: This set of tests takes no longer than 5 min in the linac treatment room. With EPID dosimetry, a consistent daily QA program can be applied, giving complete information about positioning/speed MLC. PMID: 21784685 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=5097592 Thu, 21 Jul 2011 23:00:00 +0100 5097592 http://www.medworm.com/index.php?rid=5097574&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21784686%26dopt%3DAbstract Authors: Matheoud R, Goertzen AL, Vigna L, Ducharme J, Sacchetti G, Brambilla M PET scanners require routine monitoring and quality control (QC) to ensure proper scanner performance. QC helps to ensure that PET equipment performs as specified by the manufacturer and that there have not been significant changes in the system response since acceptance. In this work we describe the maintenance history and we report on the results obtained from the PET system QC testing program over 5 years at two centers, both utilizing a Siemens Biograph 16 HiRez PET/CT system. QC testing programs were based on international standards and included the manufacturer's daily QC, monthly uniformity and sensitivity, quarterly cross-calibration and annual resolution and image quality. For the Winnipeg and Nova... Physica Medica journals http://www.medworm.com/rss/comments.php?id=5097574 Thu, 21 Jul 2011 23:00:00 +0100 5097574 http://www.medworm.com/index.php?rid=5000922&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21724438%26dopt%3DAbstract Authors: Caruana CJ, Wasilewska-Radwanska M, Aurengo A, Dendy PP, Karenauskaite V, Malisan MR, Mattson S, Meijer JH, Mihov D, Mornstein V, Rokita E, Vano E, Weckstrom M, Wucherer M This is the third of a series of articles targeted at biomedical physicists providing educational services to other healthcare professions, whether in a university faculty of medicine/health sciences or otherwise (e.g., faculty of science, hospital-based medical physics department). The first paper identified the past and present role of the biomedical physicist in the education of the healthcare professions and highlighted issues of concern. The second paper reported the results of a comprehensive SWOT (strengths, weaknesses, opportunities, threats) audit of that role. In this paper we present a strategy fo... Physica Medica journals http://www.medworm.com/rss/comments.php?id=5000922 Thu, 30 Jun 2011 23:00:00 +0100 5000922 http://www.medworm.com/index.php?rid=4955491&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21664565%26dopt%3DAbstract Authors: Meghzifene A, Nüsslin F PMID: 21664565 [PubMed - in process] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=4955491 Wed, 22 Jun 2011 19:30:14 +0100 4955491 http://www.medworm.com/index.php?rid=4855981&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21592836%26dopt%3DAbstract Authors: Betzel GT, Lansley SP, Baluti F, Reinisch L, Meyer J X-ray detectors based on single crystal diamond film made via chemical vapor deposition were investigated to evaluate their performance under clinically relevant conditions for radiotherapy dosimetry. Studies focused on repeatability, dose rate dependence, tissue phantom ratios, output factors and beam profiling. Repeatability experiments revealed a temporary loss in sensitivity due to charge detrapping effects following irradiation, which was modeled to make corrections that improved short-term precision. Dose rate dependence was observed (Fowler fitting parameter Δ = 0.96 ± 0.2) using dose rates up to ∼2 Gy min^-1. The detector statistically distinguished (n = 5, P < 0.05) between dose values separated by ... Physica Medica journals http://www.medworm.com/rss/comments.php?id=4855981 Sun, 15 May 2011 23:00:00 +0100 4855981 http://www.medworm.com/index.php?rid=4855982&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21570884%26dopt%3DAbstract CONCLUSION: Secondary and tertiary contributions were interpreted as scatter and can be subtracted from CBCT projections based on the analytical model. Therefore our model can provide a basis for improvement of image quality (less artifacts due to scatter, better contrast and resolution) in CBCT reconstruction. PMID: 21570884 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=4855982 Wed, 11 May 2011 23:00:00 +0100 4855982 http://www.medworm.com/index.php?rid=4804069&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21515082%26dopt%3DAbstract Authors: Platoni K, Diamantopoulos S, Panayiotakis G, Kouloulias V, Pantelakos P, Kelekis N, Efstathopoulos E Total Skin Electron Beam (TSEB) irradiation is considered as the treatment of choice for cutaneous T-cell lymphoma internationally, for either curative purposes or palliative care. An attempt for the first application of this external radiation therapy technique in Greece took place at the Radiation Therapy Unit of 2(nd) Department of Radiology of University of Athens at University General Hospital "Attikon". TSEB modality was developed on a linear accelerator VARIAN Clinac 2100C. To create a uniform and sufficiently large field (≈200cm×80cm) at SSD=380cm, two symmetrical 6 MeV electron beams are combined with 17.5° tilts concerning the horizontal direction. An immobilizat... Physica Medica journals http://www.medworm.com/rss/comments.php?id=4804069 Thu, 21 Apr 2011 23:00:00 +0100 4804069 http://www.medworm.com/index.php?rid=4804070&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21507693%26dopt%3DAbstract Authors: Uniyal SC, Sharma SD, Naithani UC Radiochromic film dosimetry is increasingly used in brachytherapy applications for its higher resolution ability as compared to other experimental methods. The present study was aimed to assess the accuracy and suitability of use of the improved radiochromic film model, Gafchromic EBT2, to evaluate the dose distribution in the transverse plane of microselectron HDR (192)Ir source. A specially designed and locally fabricated Polymethyl methacrylate (PMMA) phantom was used in this work for the experimental measurement of dose distribution around the source in its transverse plane. The AAPM TG-43U1 recommended radial dose function, g (r), and dose rate constant, Λ, for the source were measured using Gafchromic EBT2 film and thermoluminescent dos... Physica Medica journals http://www.medworm.com/rss/comments.php?id=4804070 Sun, 17 Apr 2011 23:00:00 +0100 4804070 http://www.medworm.com/index.php?rid=4804071&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21501966%26dopt%3DAbstract This study investigates the reproducibility of the reconstructed image sharpness, after modifications of the geometry setup, for a variable magnification micro-CT (μCT) scanner. All the measurements were performed on a novel engineered μCT scanner for in vivo imaging of small animals (Xalt), which has been recently built at the Institute of Clinical Physiology of the National Research Council (IFC-CNR, Pisa, Italy), in partnership with the University of Pisa. The Xalt scanner is equipped with an integrated software for on-line geometric recalibration, which will be used throughout the experiments. In order to evaluate the losses of image quality due to modifications of the geometry setup, we have made 22 consecutive acquisitions by changing alternatively the system geometry between two d... Physica Medica journals http://www.medworm.com/rss/comments.php?id=4804071 Fri, 15 Apr 2011 23:00:00 +0100 4804071 http://www.medworm.com/index.php?rid=4804073&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21497123%26dopt%3DAbstract Authors: Brix G, Ravesh MS, Zwick S, Griebel J, Delorme S Concentration-time courses measured by dynamic contrast-enhanced (DCE) imaging can be described by a convolution of the arterial input with an impulse response function, Q(T)(t), characterizing tissue microcirculation. Data analysis is based on two different approaches: computation of Q(T)(t) by algebraic deconvolution (AD) and subsequent evaluation according to the indicator dilution theory (IDT) or parameterization of Q(T)(t) by analytical expressions derived by compartmental modeling. Pitfalls of both strategies will be addressed in this study. Tissue data acquired by DCE-CT in patients with head-and-neck cancer and simulated by a reference model (MMID4) were analyzed by a two-compartment model (TCM), a permeability-limited t... Physica Medica journals http://www.medworm.com/rss/comments.php?id=4804073 Wed, 13 Apr 2011 23:00:00 +0100 4804073 http://www.medworm.com/index.php?rid=4804072&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21497530%26dopt%3DAbstract Authors: Ghetti C, Ortenzia O, Serreli G Although iterative reconstruction is widely applied in SPECT/PET, its introduction in clinical CT is quite recent, in the past the demand for extensive computer power and long image reconstruction times have stopped the diffusion of this technique. Recently Iterative Reconstruction in Image Space (IRIS) has been introduced on Siemens top CT scanners. This recon method works on image data area, reducing the time-consuming loops on raw data and noise removal is obtained in subsequent iterative steps with a smoothing process. We evaluated image noise, low contrast resolution, CT number linearity and accuracy, transverse and z-axis spatial resolution using some dedicated phantoms in single, dual source and cardiac mode. We reconstructed images with ... Physica Medica journals http://www.medworm.com/rss/comments.php?id=4804072 Wed, 13 Apr 2011 23:00:00 +0100 4804072 http://www.medworm.com/index.php?rid=4804074&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21486704%26dopt%3DAbstract This study established that the relationship between the beam weights and effective wedge angles implemented for the motorized wedge filter of medical linacs is not directly applicable for the motorized wedge filter of Telecobalt. PMID: 21486704 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=4804074 Sat, 09 Apr 2011 23:00:00 +0100 4804074 http://www.medworm.com/index.php?rid=4697464&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21459642%26dopt%3DAbstract Authors: Mady MM, Allam MA The effect of microwave exposure on liposome at non-thermal level are studied. Dipalmitoyl phosphatidylcholine (DPPC) liposomes were exposed to 950 MHz at power densities of 2.5 mW/cm(2), which is equivalent to specific absorption rate (SAR) of 0.238 W/K. The interaction of microwave with liposomes was investigated by membrane solubilization measurements using a non-ionic detergent, octylglucoside (OG), as well as Fourier transform infrared (FTIR) spectroscopy and flow activation energy measurements. The amount of detergent needed to completely solubilize the liposomal membrane was increased after exposure of liposomes to microwave irradiation, indicating an increased membrane resistance to the detergent and hence a change in the natural membrane permeatio... Physica Medica journals http://www.medworm.com/rss/comments.php?id=4697464 Thu, 31 Mar 2011 23:00:00 +0100 4697464 http://www.medworm.com/index.php?rid=4638061&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21420340%26dopt%3DAbstract CONCLUSION: The technique described for determining the SSD and the generation of respiratory signals using lasers is cost effective and simple to implement. PMID: 21420340 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=4638061 Thu, 17 Mar 2011 00:00:00 +0100 4638061 http://www.medworm.com/index.php?rid=4638062&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21419682%26dopt%3DAbstract Authors: Martinez LC, Calzado A, Rodriguez C, Gilarranz R, Manzanas MJ A method to carry out stoichiometric calibrations of CT scanners employed in radiotherapy treatment planning is proposed. The method is based on a simple parametrization of the CT number of a substance, which involves only two variables to describe the substance (electron density and one effective atomic number) and one parameter to describe the beam. The method was tested experimentally on a group of beams. A set of no tissue-like substances of known densities and elemental compositions were employed as calibrators. CT number-to-density curves (RED curves) were calculated with the proposed parametrization and compared to those measured with a commercial density phantom. Differences between the electron densities as... Physica Medica journals http://www.medworm.com/rss/comments.php?id=4638062 Wed, 16 Mar 2011 00:00:00 +0100 4638062 http://www.medworm.com/index.php?rid=4470715&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21310641%26dopt%3DAbstract Authors: Ariga E, Ito S, Deji S, Saze T, Nishizawa K A method for determining half value layers (HVLs) of inverter-type X-ray equipment using a computed radiography (CR) systems was developed. This method is similar to the traditional method, where the air kerma (K) is measured using an ionization based dosimeter and increasing aluminum (Al) absorber thickness, but utilized an imaging plate (IP) and the sensitivity index (S number) of the CR system as the dosimeter and the dosimeter reading, respectively. The IP and the S number were calibrated using an ionization chamber having traceability to the National Standard Ionization Chamber. A modified version of the S number definition equation K=a×S(-b) was used to translate the S number to K values for X-ray beams produced using tube vol... Physica Medica journals http://www.medworm.com/rss/comments.php?id=4470715 Tue, 08 Feb 2011 00:00:00 +0100 4470715 http://www.medworm.com/index.php?rid=4470716&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21292523%26dopt%3DAbstract Authors: Webb S In this brief Letter the arguments of Sherouse in 2002, that the delivery of intensity-modulated radiation therapy (IMRT) does not necessarily require a multileaf collimator (MLC), are extended with specific reference to the possibility to use the jaws-only (JO) of an accelerator or some moving mask. With reference to the work in the last decade to develop JO IMRT the argument is made that it is not just the limitations of JO that are precluding its commercial development but also the commercial/business and reimbursement situations. A new moving-mask-IMRT technique that has high monitor-unit (MU) efficiency, but low MU per component, is illustrated. The Letter is intended to stimulate debate and is not a criticism by the author of current MLC-based IMRT. PMID: 2129... Physica Medica journals http://www.medworm.com/rss/comments.php?id=4470716 Tue, 01 Feb 2011 00:00:00 +0100 4470716 http://www.medworm.com/index.php?rid=4400275&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21251862%26dopt%3DAbstract In this study version 5 of the MCNP photon transport simulation was used to calculate the dosimetric parameters for new palladium brachytherapy source design following AAPM Task Group No. 43U1 report. The internal source components include four resin beads of 0.6 mm diameters with (103)Pd uniformly absorbed inside and one cylindrical copper marker with 1.5 mm length. The resin beads and marker are then encapsulated within 0.8 mm in diameter and 4.5 mm long cylindrical capsule of titanium. The dose rate constant, Λ, line and point-source radial dose function, g(L)(r) and g(P)(r), and the anisotropy function, F(r,θ) of the IR01-(103)Pd seed have been calculated at distances from 0.25 to 5 cm. All the results are in good agreement with previously published thermoluminescence-dosimeter ... Physica Medica journals http://www.medworm.com/rss/comments.php?id=4400275 Tue, 18 Jan 2011 00:00:00 +0100 4400275 http://www.medworm.com/index.php?rid=4335934&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21216645%26dopt%3DAbstract This study aimed to estimate fetal dose from mantle field irradiation with 6MV photons and to determine the proper fetal shielding conditions. The Monte Carlo N-particle code and mathematical phantoms representing pregnancy at the first, second and third trimesters of gestation were used to calculate fetal dose with or without the presence of a 5-cm-thick lead shield of dimensions 35×35cm(2). Fetal exposure was calculated for lead thicknesses of 2, 3, 4, 6, 7 and 8cm. The dependence of fetal dose upon the distance separating the shield from the beam edge and phantom's abdomen was investigated. Dose measurements were performed on a physical phantom using thermoluminescent dosimetry. The radiation dose to an unshielded and shielded fetus was 0.578-0.861% and 0.180-0.641% of the prescribed t... Physica Medica journals http://www.medworm.com/rss/comments.php?id=4335934 Fri, 07 Jan 2011 00:00:00 +0100 4335934 http://www.medworm.com/index.php?rid=4335933&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21216646%26dopt%3DAbstract This study involved retrospective analyses of entrance surface dose and dose-width-product measurements obtained in Irish Dental Practices for both Intra-Oral and Panoramic units respectively, followed by comparisons with Monte-Carlo generated computer models of these procedures. Analysis was performed on data from 33 Intra-Oral units for an Adult Mandibular Molar entrance surface dose, 198 readings for a proposed mGy/mAs reference level and 50 Panoramic machines for a dose-width product investigation. The third quartile value of the entrance surface dose for a standard Adult Mandibular Molar Intra-Oral radiograph is (2.40 ± 0.92)mGy, compared to a computer-modelled value of 2.60 mGy. The third quartile mGy/mAs value for Intra-Oral procedures is (1.03 ± 0.38)mGy/mAs, compared to a c... Physica Medica journals http://www.medworm.com/rss/comments.php?id=4335933 Fri, 07 Jan 2011 00:00:00 +0100 4335933 http://www.medworm.com/index.php?rid=4335935&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21216170%26dopt%3DAbstract Authors: Manjunatha HC, Rudraswamy B The Bremsstrahlung exposure induced by some of the therapeutic beta nuclides ((90)Y, (143)Pm, (169)Er, (204)Tl, (210)Bi, (89)Sr, (45)Ca and (131)I) in DNA and RNA has been calculated by extending the national council for radiation protection model. It has estimated the specific Bremsstrahlung constant (Γ(Br)), Probability of energy loss by beta during Bremsstrahlung emission (P(Br)) and Bremsstrahlung activity (A(release))(Br). The estimated Bremsstrahlung activities of pure beta nuclides in DNA and RNA are extremely large (10(2) GBq-10(6) GBq). The patients receiving such nuclides would never receive that much activity because of prohibitive radiation toxicity (few 100 MBq). Thus the patients receiving these pure beta emitting nuclides do not h... Physica Medica journals http://www.medworm.com/rss/comments.php?id=4335935 Thu, 06 Jan 2011 00:00:00 +0100 4335935 http://www.medworm.com/index.php?rid=4335936&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21215671%26dopt%3DAbstract CONCLUSION: IMRT for whole abdominal irradiation in patients with advanced ovarian carcinoma is applicable and feasible though treatment planning is complex and time-consuming. There is a significant reduction of dose to critical organs by using IMRT while maintaining target volume coverage. PMID: 21215671 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=4335936 Wed, 05 Jan 2011 00:00:00 +0100 4335936 http://www.medworm.com/index.php?rid=4185014&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21074467%26dopt%3DAbstract CONCLUSIONS: The paper recommends use of modified CADD parameters for treatment planning, if calibration of output is carried out in the presence of beam spoiler. PMID: 21074467 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=4185014 Wed, 10 Nov 2010 00:00:00 +0100 4185014 http://www.medworm.com/index.php?rid=4185013&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21074468%26dopt%3DAbstract Authors: Givehchi N, Marchetto F, Valastro LM, Ansarinejad A, Attili A, Garella MA, Giordanengo S, Monaco V, Montero JP, Sacchi R, Boriano A, Bourhaleb F, Cirio R, La Rosa A, Pecka A, Peroni C, Cirrone GA, Cuttone G, Donetti M, Iliescu S, Pittera S, Raffaele L A detector (MOPI) has been developed for the online monitoring of the beam at the Centro di AdroTerapia e Applicazioni Nucleari Avanzate (CATANA), where shallow tumours of the ocular region are treated with 62 MeV protons. At CATANA the beam is passively spread to match the tumour shape. The uniformity of the delivered dose depends on beam geometrical quantities which are checked before each treatment. However, beam instabilities might develop during the irradiation affecting the dose distribution. This paper reports on the use ... Physica Medica journals http://www.medworm.com/rss/comments.php?id=4185013 Wed, 10 Nov 2010 00:00:00 +0100 4185013 http://www.medworm.com/index.php?rid=4185012&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21074469%26dopt%3DAbstract Authors: D'Ercole L, Thyrion FZ, Bocchiola M, Mantovani L, Klersy C The aim of this study was to propose local diagnostic reference levels (DRL) for exposure to radiation during diagnostic procedures and neuroradiological interventions such as cerebral angiography and embolisation of cerebral aneurysms (intra-cranial aneurysms and arteriovenous malformations). Hospitals should adopt the national DRLs for use locally or establish their own DRLs based on local practice, if sufficient local data are available. For this purpose we studied a sample of 113 cerebral angiography procedures and 82 embolisations of cerebral aneurysms. The data recorded included the kerma-area product (KAP), the fluoroscopy time and the number of frames for each procedure: third quartiles from the total dosimetri... Physica Medica journals http://www.medworm.com/rss/comments.php?id=4185012 Wed, 10 Nov 2010 00:00:00 +0100 4185012 http://www.medworm.com/index.php?rid=4166124&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21071252%26dopt%3DAbstract Authors: Scafè R, Auer P, Bennati P, La Porta L, Pisacane F, Cinti MN, Pellegrini R, De Vincentis G, Conte G, Pani R The public domain code GENIA, based on multi-printing method for producing surface sources with appropriate radioactivity, is described. The conventional technique, running on standard inkjet printer with radio-marked ink filling, is improved by repeating elementary printing commands in the same band. Well outlined sources with adjustable radioactivity can be obtained without refilling. The intrinsic limitation of printable radioactivity, depending on the value available at nozzles at printing time, was overcome. In addition the method permits the accurate calibration of the amount of activity released onto the paper. PMID: 21071252 [PubMed - as supplied by publishe... Physica Medica journals http://www.medworm.com/rss/comments.php?id=4166124 Tue, 09 Nov 2010 00:00:00 +0100 4166124 http://www.medworm.com/index.php?rid=4166123&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21071253%26dopt%3DAbstract CONCLUSION: These results may explain the current inadequacy of our treatment techniques in preventing locoregional recurrences of GBM. PMID: 21071253 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=4166123 Tue, 09 Nov 2010 00:00:00 +0100 4166123 http://www.medworm.com/index.php?rid=4152764&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21055989%26dopt%3DAbstract Authors: Moser T, Fleischhacker S, Schubert K, Sroka-Perez G, Karger CP In conformal radiotherapy, careful setup of the patient and setup verification prior to irradiation is essential. The technical performance of a commercial 3D-surface imaging system (Galaxy, LAP Laser, Lüneburg, Germany) for patient setup correction was evaluated. The system reconstructs a 3D-surface model by scanning the patient with a laser line while a camera records its reflections. This surface model is then compared with a reference model and a setup correction with 6 degrees of freedom is derived. The calibration stability of the system was investigated using the daily check phantom of the manufacturer. The accuracy and reproducibility of the system were investigated with an anthropomorphic phantom by perfo... Physica Medica journals http://www.medworm.com/rss/comments.php?id=4152764 Wed, 03 Nov 2010 00:00:00 +0100 4152764 http://www.medworm.com/index.php?rid=4139553&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21051256%26dopt%3DAbstract In this study, the beam characteristics of both static (ST) and segmental intensity-modulated (IM) beams were investigated at various dose rates for 6 and 18 MV at low MU settings. Dose linearity was investigated for both the ST and the IM beams. For the ST beams, standard 10 × 10 cm(2) fields were irradiated with MU values ranging from 1 to 100. For the IM beams, 10 × 10 cm(2) and 15 × 15 cm(2) fields were used as subfields. The normalized dose (ND)/MU was obtained. Beam flatness and symmetry for 2 and 10 MU was measured by in-plane (G-T) and cross-plane (R-L) profiles using Kodak XV films. The largest dose/MU discrepancies were observed for 1 MU. For the ST beams, the beam output decreased up to 4.5% for 1 MU at the high dose rates of 6 and 18 MV. Dose variations were le... Physica Medica journals http://www.medworm.com/rss/comments.php?id=4139553 Wed, 03 Nov 2010 00:00:00 +0100 4139553 http://www.medworm.com/index.php?rid=4139554&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21050785%26dopt%3DAbstract Authors: Devic S In radiation therapy, an accurate dose determination and a precise dose delivery to the tumour are directly associated with better treatment outcomes in terms of higher tumour control and lower post radiation therapy complications. Over the years, film dosimetry was developed into a powerful tool for radiotherapy treatment verification and quality assurance. This review summarizes development of GAFCHROMIC™ film models through improvement in their sensitivity and uniformity as two dimensional detectors. The most important characteristics as well as the limitations that can affect the performance of the radiochromic film dosimetry systems have been described. An outline of both clinical and research contemporary applications is given particularly emphasizing new appli... Physica Medica journals http://www.medworm.com/rss/comments.php?id=4139554 Mon, 01 Nov 2010 00:00:00 +0100 4139554 http://www.medworm.com/index.php?rid=4139555&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21035371%26dopt%3DAbstract CONCLUSIONS: This study indicates the superiority of H over B mode, in terms of spatial resolution, relative contrast, and overall image quality. Thus H mode has the potential benefit in prostate brachytherapy. This study provides the basis to move forward to investigate whether the superior image quality observed in the laboratory can be translated into a higher treatment quality for the patient. PMID: 21035371 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=4139555 Wed, 27 Oct 2010 00:00:00 +0100 4139555 http://www.medworm.com/index.php?rid=4088283&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20034828%26dopt%3DAbstract In this study, recommendations of the AAPM TG-43U1 report have been followed to characterize the Varisource VS2000 (192)Ir high dose rate source, provided by Varian Oncology Systems. In order to obtain dosimetric parameters for this source, Monte Carlo calculations with PENELOPE code have been carried out. TG-43 formalism parameters have been presented, i.e., air kerma strength, dose rate constant, radial dose function and anisotropy function. Besides, a 2D Cartesian coordinates dose rate in water table has been calculated. These quantities are compared to this source reference data, finding results in good agreement with them. The data in the present study complement published data in the next aspects: (i) TG-43U1 recommendations are followed regarding to phantom ambient conditions and to... Physica Medica journals http://www.medworm.com/rss/comments.php?id=4088283 Sat, 23 Oct 2010 09:10:04 +0100 4088283 http://www.medworm.com/index.php?rid=4088282&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20400349%26dopt%3DAbstract Authors: Chaniotis AK, Kaiktsis L, Katritsis D, Efstathopoulos E, Pantos I, Marmarellis V The spatial and temporal distributions of wall shear stress (WSS) in prototype vessel geometries of coronary segments are investigated via numerical simulation, and the potential association with vascular disease and specifically atherosclerosis and plaque rupture is discussed. In particular, simulation results of WSS spatio-temporal distributions are presented for pulsatile, non-Newtonian blood flow conditions for: (a) curved pipes with different curvatures, and (b) bifurcating pipes with different branching angles and flow division. The effects of non-Newtonian flow on WSS (compared to Newtonian flow) are found to be small at Reynolds numbers representative of blood flow in coronary arteries. Sp... Physica Medica journals http://www.medworm.com/rss/comments.php?id=4088282 Sat, 23 Oct 2010 09:10:04 +0100 4088282 http://www.medworm.com/index.php?rid=4088281&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20951072%26dopt%3DAbstract This study also revealed the preference of the majority of institutes the last 20 years in "six dual field technique" at a high dose rate, which is a safe and effective treatment. PMID: 20951072 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=4088281 Tue, 12 Oct 2010 23:00:00 +0100 4088281 http://www.medworm.com/index.php?rid=4003841&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20864370%26dopt%3DAbstract In this study twenty patients were enrolled and were treated with [(153)Sm]Sm-EDTMP, administering a fixed activity per kilogram (37 MBq/kg); blood and urine samples were collected during 24 h post treatment. The median value of the administered activity was 2.7 GBq. Blood clearance confirmed that an aliquot of [(153)Sm]Sm-EDTMP rapidly localizes and is retained in bone, while the remainder is rapidly cleared from the blood pool by the urinary system. Our data show a bi-exponential clearance from blood: the rapid component has a half life median value of 6 min (range: 2-24 min), while the slow one has a half life median value of 1.4 h (range: 0.6-5.8 h). Median value of the urinary excretion is 40 (range: 3-75) % of the administered activity. Our model shows the behavi... Physica Medica journals http://www.medworm.com/rss/comments.php?id=4003841 Tue, 21 Sep 2010 23:00:00 +0100 4003841 http://www.medworm.com/index.php?rid=3854898&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20696607%26dopt%3DAbstract Authors: Lehmpfuhl MC, Hess A, Gaudnek MA, Sibila M The exact knowledge of the blood vessel geometry plays an important role, not only in clinical applications (stroke diagnosis, detection of stenosis), but also for deeper analysis of hemodynamic functional data, such as fMRI. Such vessel geometries can be obtained by different MR angiographic measurements. It is shown that simulations using computational fluid dynamics (CFD) can be used to validate the vessel geometry, automatically reconstructed from time of flight (TOF) angiograms or phase contrast angiography (PC-MRA) data. CFD simulations are based on PC-MRA data, since these data contain additionally rheological information (phases) besides merely amplitudes as is the case for TOF measurements. Parts of the rat brain vessel syste... Physica Medica journals http://www.medworm.com/rss/comments.php?id=3854898 Fri, 06 Aug 2010 23:00:00 +0100 3854898 http://www.medworm.com/index.php?rid=3823903&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20674429%26dopt%3DAbstract Authors: Kisielewicz K, Truszkiewicz A, Wach S, Wasilewska-Radwańska M Dose Area Product (DAP) meters which measure in units of [Gy*m(2)], are widely used in radiology, fluoroscopy and interventional cardiology X-ray units. However, assessment of the radiological hazard to the patient undergoing a given diagnostic procedure cannot be readily obtained from the measured value of DAP. We also developed simple relationships between Entrance Surface Dose (ESD) and the DAP value measured in air, for different collimator field sizes and patient thickness. To establish these relationships, measurements were performed in a water phantom using high-sensitive thermoluminescent detectors (LiF:Mg,Cu,P) calibrated in terms of Kerma in water. Using these relationships developed for a given X-ray u... Physica Medica journals http://www.medworm.com/rss/comments.php?id=3823903 Wed, 28 Jul 2010 23:00:00 +0100 3823903 http://www.medworm.com/index.php?rid=3792556&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20655782%26dopt%3DAbstract In conclusion, the dose calculation algorithm of TPP version 3.8 showed good accuracy for a 6 MV photon beam provided beam hardening and softening parameters are taken into account. From the results, it is also concluded that, the beam hardening, beam softening and attenuation coefficients along with wedge geometry and measured wedge factor at single depth and multiple fields sizes can be the replacement of wedged profile and wedged cross-sectional data in the TPS. The study also indicated that by ignoring the beam softening and beam hardening will result in an inaccurate dose to the target volume of the patient. PMID: 20655782 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=3792556 Wed, 21 Jul 2010 23:00:00 +0100 3792556 http://www.medworm.com/index.php?rid=3742499&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20615735%26dopt%3DAbstract CONCLUSIONS: The proposed method for in vivo dose verification is very simple to implement and to use in clinics. Measurements can be repeated during several sessions giving the opportunity to built new strategies for the validation by statistical evaluation of the data. The trending of in vivo dose along the treatment becomes also possible. The number of checkable beams is also increased by this method. PMID: 20615735 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=3742499 Mon, 05 Jul 2010 23:00:00 +0100 3742499 http://www.medworm.com/index.php?rid=3724862&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20591711%26dopt%3DAbstract Authors: Yoshimura K, Shimamoto K, Ikeda M, Ichikawa K, Naganawa S The purpose of this study was to clarify whether non-medical-grade liquid crystal displays (LCDs) are acceptable for the soft-copy reading of brain CTs. Four kinds of color LCDs with different image quality levels were used: medical-grade LCD, low-grade general LCD calibrated with the grayscale display function (GSDF), low-grade general LCD calibrated with gamma 2.2 and a notebook personal computer display panel. In Osirix's standard window setting for brain CTs, the average CT values of brain parenchyma in 100 cases were correlated with a grayscale level ranging from 71 to 91 in a 256-step grayscale. At these gray levels, the image contrast on the two low-grade LCDs calibrated with gamma 2.2 was higher than that on the... Physica Medica journals http://www.medworm.com/rss/comments.php?id=3724862 Sun, 27 Jun 2010 23:00:00 +0100 3724862 http://www.medworm.com/index.php?rid=3708101&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20579913%26dopt%3DAbstract Authors: Kanematsu N This work addresses computing techniques for dose calculations in treatment planning with proton and ion beams, based on an efficient kernel-convolution method referred to as grid-dose spreading (GDS) and accurate heterogeneity-correction method referred to as Gaussian beam splitting. The original GDS algorithm suffered from distortion of dose distribution for beams tilted with respect to the dose-grid axes. Use of intermediate grids normal to the beam field has solved the beam-tilting distortion. Interplay of arrangement between beams and grids was found as another intrinsic source of artifact. Inclusion of rectangular-kernel convolution in beam transport, to share the beam contribution among the nearest grids in a regulatory manner, has solved the interplay probl... Physica Medica journals http://www.medworm.com/rss/comments.php?id=3708101 Tue, 22 Jun 2010 23:00:00 +0100 3708101 http://www.medworm.com/index.php?rid=3673083&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20554236%26dopt%3DAbstract Authors: González-Castaño DM, Gómez F, Brualla L, Roselló JV, Planes D, Sánchez M, Pombar M Radiosurgery and intensity modulated radiation therapy (IMRT) treatments are based on the delivery of narrow and/or irregularly shaped megavoltage photon beams. This kind of beams present both lack of charged particle equilibrium and steep dose gradients. Quality assurance (QA) measurements involved in these techniques must therefore be carried out with a dosimeter featuring high small volume. In order to obtain a good signal to noise ratio, a relatively dense material is needed as active medium. Non-polar organic liquids were proposed as active mediums with both good tissue equivalence and showing high signal to noise ratio. In this work, a liquid-filled ionization chamber is pre... Physica Medica journals http://www.medworm.com/rss/comments.php?id=3673083 Wed, 26 May 2010 23:00:00 +0100 3673083 http://www.medworm.com/index.php?rid=3530712&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20434382%26dopt%3DAbstract Authors: Chica U, Flórez G, Anguiano M, Lallena AM A simple analytical expression aiming to calculate the backscatter factor used in dosimetry protocols to determine the absorbed dose in water for low energy X-rays beams is presented. This expression is based on the linear dependence of the backscatter factor with the generating potential, for fixed values of the half-value layer. The results of a recent work in which 74 X-ray beams with different spectroscopic characteristics, generated with the code xcomp5r and transported with the Monte Carlo code penelope have been used. The expression derived permits to calculate the backscatter factor within 5% accuracy. The predictive power of this expression has been tested for 20 X-ray beams generated with potentials from 50 to 250kV, for w... Physica Medica journals http://www.medworm.com/rss/comments.php?id=3530712 Tue, 27 Apr 2010 23:00:00 +0100 3530712 http://www.medworm.com/index.php?rid=3386116&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20299733%26dopt%3DAbstract In this study, we introduce an improved scheme for segmenting IPCs. It consists of two main components. One is geodesic distance-based merging, which merges suspicious patches (SPs) for IPCs. Based on the merged SPs, another component, called convex dilation, grows each SP beyond the inner surface of the colon wall to form a volume of interest (VOI) for that IPC, so that the inner border of the VOI beyond the colon inner surface could be segmented as convex, as expected. The IPC segmentation strategy was evaluated using a database of 50 patient studies, which include 100 scans at supine and prone positions with 84 polyps and masses sized from 6 to 35 mm. The presented IPC segmentation strategy (or VOI extraction method) demonstrated improvements, in terms of having no undesirably merged tr... Physica Medica journals http://www.medworm.com/rss/comments.php?id=3386116 Sun, 21 Mar 2010 06:40:06 +0100 3386116 http://www.medworm.com/index.php?rid=3284669&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20157225%26dopt%3DAbstract Authors: Wang LL, Rogers DW In this letter we reply to the letter by Professor Andreo (Andreo 2010 Phys. Med. Biol. 55 L9-16) regarding the values of the replacement correction factor for cylindrical chambers, which in turn commented on our recent paper on this (Wang and Rogers 2009 Phys. Med. Biol. 54 1609-20). PMID: 20157225 [PubMed - in process] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=3284669 Fri, 19 Feb 2010 07:34:09 +0100 3284669 http://www.medworm.com/index.php?rid=3284668&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20157227%26dopt%3DAbstract Authors: Andreo P The authors of a recent paper (Wang and Rogers 2009 Phys. Med. Biol. 54 1609) have used the Monte Carlo method to simulate the 'classical' experiment made more than 30 years ago by Johansson et al (1978 National and International Standardization of Radiation Dosimetry (Atlanta 1977) vol 2 (Vienna: IAEA) pp 243-70) on the displacement (or replacement) perturbation correction factor p(dis) for cylindrical chambers in (60)Co and high-energy photon beams. They conclude that an 'unreasonable normalization at d(max)' of the ionization chambers response led to incorrect results, and for the IAEA TRS-398 Code of Practice, which uses ratios of those results, 'the difference in the correction factors can lead to a beam calibration deviation of more than 0.5% for Farmer-like cha... Physica Medica journals http://www.medworm.com/rss/comments.php?id=3284668 Fri, 19 Feb 2010 07:34:05 +0100 3284668 http://www.medworm.com/index.php?rid=3244752&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20124652%26dopt%3DAbstract Authors: Patrick Reilly J A recent electrostimulation study with human subjects (Recoskie et al 2009 Phys. Med. Biol. 54 5965-79) reported a large difference between chronaxie times when stimuli were delivered to the same body locus (the wrist) either through contact electrodes (electric stimulation) or through a pulsed magnetic field (magnetic stimulation). This paper reviews the procedures and analytic methods used in that study that might account for the reported discrepancies. Factors possibly accounting for reported discrepancies include the maximum and minimum pulse widths of the experimental stimuli; variations in experimental waveforms vis-à-vis mathematically ideal functions; differences in the spatial distribution of the in situ electric field for the two methods of deli... Physica Medica journals http://www.medworm.com/rss/comments.php?id=3244752 Sat, 06 Feb 2010 05:44:05 +0100 3244752 http://www.medworm.com/index.php?rid=3179074&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20071761%26dopt%3DAbstract Authors: Dalah E, Bradley D, Nisbet A There is much interest in positron emission tomography (PET) for measurements of regional tracer concentration in hypoxic tumour-bearing tissue, focusing on the need for accurate radiotherapy treatment planning. Generally, relevant data are taken over multiple time frames in the form of tissue activity curves (TACs), thus providing an indication of vasculature structure and geometry. This is a potential key in providing information on cellular perfusion and limited diffusion. A number of theoretical studies have attempted to describe tracer uptake in tissue cells in an effort to understand such complicated behaviour of cellular uptake and the mechanism of washout. More recently, a novel computerized reaction diffusion equation method was developed ... Physica Medica journals http://www.medworm.com/rss/comments.php?id=3179074 Sat, 16 Jan 2010 17:10:05 +0100 3179074 http://www.medworm.com/index.php?rid=3130035&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20036595%26dopt%3DAbstract Authors: Imai K, Ikeda M, Enchi Y, Niimi T By using the CT images obtained by subtracting two CT images acquired under the same conditions and slice locations, we have devised a method for detecting streak artifacts in non-uniform regions and only radiological noise components in CT images. A chest phantom was scanned using 16- and 64-multidetector row helical CT scanners with various mAs values at 120kVp. The upper lung slice image was employed as a target image for evaluating the streak artifacts and radiological noise. One hundred parallel line segments with a length of 80 pixels were placed on the subtracted CT image, and the largest CT value in each CT value profile was employed as a feature variable of the streak artifacts; these feature variables were analyzed with the extreme v... Physica Medica journals http://www.medworm.com/rss/comments.php?id=3130035 Thu, 24 Dec 2009 00:00:00 +0100 3130035 http://www.medworm.com/index.php?rid=3130036&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20036176%26dopt%3DAbstract Authors: Bentayeb F, Nfaoiu K, Basraoui O, Azevedo AC This work consists on a survey of the performance of viewing boxes installed in diagnostic radiology departments and included several aspects: checking the illuminance of the diagnostic rooms where the viewing boxes are located as well as the viewing boxes luminance levels and homogeneity. Seven hospitals took part in the survey, being three in the city of Casablanca and four in Rabat. A total of 136 viewing boxes and 18 diagnostic rooms have been checked. It was found that one diagnostic room works under normal conditions and that 80% of the viewing boxes present luminance levels below the international recommendations and the homogeneity is inadequate in 85%. Some simple and cheap initiatives can be performed in these departments ... Physica Medica journals http://www.medworm.com/rss/comments.php?id=3130036 Wed, 23 Dec 2009 00:00:00 +0100 3130036 http://www.medworm.com/index.php?rid=3122599&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20034828%26dopt%3DAbstract In this study, recommendations of the AAPM TG-43U1 report have been followed to characterize the Varisource VS2000 (192)Ir high dose rate source, provided by Varian Oncology Systems. In order to obtain dosimetric parameters for this source, Monte Carlo calculations with PENELOPE code have been carried out. TG-43 formalism parameters have been presented, i.e., air kerma strength, dose rate constant, radial dose function and anisotropy function. Besides, a 2D Cartesian coordinates dose rate in water table has been calculated. These quantities are compared to this source reference data, finding results in good agreement with them. The data in the present study complement published data in the next aspects: (i) TG-43U1 recommendations are followed regarding to phantom ambient conditions and to... Physica Medica journals http://www.medworm.com/rss/comments.php?id=3122599 Tue, 22 Dec 2009 00:00:00 +0100 3122599 http://www.medworm.com/index.php?rid=3122598&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20034829%26dopt%3DAbstract Authors: Marcu L, Bezak E Advanced head and neck cancers are one of the most challenging cancers facing the oncologists due to their aggressiveness attributable to the high hypoxic content and the tumour's ability to repopulate during radiotherapy. Alterations of radiotherapy fractionation schedules are possible ways to improve tumour control. Clinical trials have shown that both hyperfractionated radiotherapy (multiple fractions a day, over the same treatment time), and accelerated radiotherapy (higher doses per fraction, six days a week, over 5 weeks or less) are more effective than conventional radiotherapy in the management of head and neck cancer. However, the treatment choice between hyperfractionated and accelerated radiotherapy is still debated, due to very similar results obta... Physica Medica journals http://www.medworm.com/rss/comments.php?id=3122598 Tue, 22 Dec 2009 00:00:00 +0100 3122598 http://www.medworm.com/index.php?rid=3112799&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20022275%26dopt%3DAbstract Authors: Craft D A discrete set of points and their convex combinations can serve as a sparse representation of the Pareto surface in multiple objective convex optimization. We develop a method to evaluate the quality of such a representation, and show by example that in multiple objective radiotherapy planning, the number of Pareto optimal solutions needed to represent Pareto surfaces of up to five dimensions grows at most linearly with the number of objectives. The method described is also applicable to the representation of convex sets. PMID: 20022275 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=3112799 Thu, 17 Dec 2009 00:00:00 +0100 3112799 http://www.medworm.com/index.php?rid=3067430&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19966342%26dopt%3DAbstract Authors: Maler A, Lutscher F Mechanistic dynamic cell population models for the tumour control probability (TCP) to date have used a simplistic representation of the cell cycle: either an exponential cell-cycle time distribution (Zaider & Minerbo, 2000, Tumour control probability: a formulation applicable to any temporal protocol of dose delivery. Phys. Med. Biol., 45, 279-293) or a two-compartment model (Dawson & Hillen, 2006, Derivation of the tumour control probability (TCP) from a cell cycle model. Comput. Math. Methods Med., 7, 121-142; Hillen, de Vries, Gong & Yurtseven, 2009, From cell population models to tumour control probability: including cell cycle effects. Acta Oncol. (submitted)). Neither of these simplifications captures realistic cell-cycle time distributio... Physica Medica journals http://www.medworm.com/rss/comments.php?id=3067430 Sun, 06 Dec 2009 00:00:00 +0100 3067430 http://www.medworm.com/index.php?rid=3067431&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19963422%26dopt%3DAbstract Using the "STEP Test" to evaluate processing speed in Moroccan hospitals. Phys Med. 2009 Dec 5; Authors: Nfaoiu K, Bentayeb F, Basraoui O, Azevedo AC The STEP Test is a simple method that can be used to quickly evaluate processing speed of automatic processors. It allows the identification of large deviations (>20%) in the processor-chemicals-film system. STEP means Sensitometric Test for the Evaluation of Processing. The performance of the processors taking part in the survey are calculated and compared to a standard processor where the film is processed under ideal conditions, according to manufacturer's recommendations. For each processor, in the dark room, a film is exposed to a sensitometer light, processed and the sensitometric curve is obtained. This survey was perfor... Physica Medica journals http://www.medworm.com/rss/comments.php?id=3067431 Sat, 05 Dec 2009 00:00:00 +0100 3067431 http://www.medworm.com/index.php?rid=3015741&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19926506%26dopt%3DAbstract Authors: Huang Y, Willomitzer C, Zakaria GA, Hartmann GH Measurements of depth-dose curves in water phantom using a cylindrical ionization chamber require that its effective point of measurement is located at the measuring depth. Recommendations for the position of the effective point of measurement with respect to the central axis valid for high-energy electron and photon beams are given in dosimetry protocols. According to these protocols, the use of a constant shift P(eff) is currently recommended. However, this is still based on a very limited set of experimental results. It is therefore expected that an improved knowledge of the exact position of the effective point of measurement will further improve the accuracy of dosimetry. Recent publications have revealed that the position o... Physica Medica journals http://www.medworm.com/rss/comments.php?id=3015741 Mon, 16 Nov 2009 00:00:00 +0100 3015741 http://www.medworm.com/index.php?rid=2972224&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19893382%26dopt%3DAbstract Authors: Weiss KB Weiss KB: Experiri: Building the pathway to best recognize those who strive to master the art of the practice of medicine. Am J Phys Med Rehabil 2009;88:867-872. PMID: 19893382 [PubMed - in process] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=2972224 Sun, 01 Nov 2009 00:00:00 +0100 2972224 http://www.medworm.com/index.php?rid=2972223&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19893383%26dopt%3DAbstract CONCLUSIONS:: The results of this study demonstrate that turning capacity poststroke is compromised, as exemplified by the greater number of steps and time required to complete turns at each angle tested. Turning capacity was related to the degree of gait asymmetry and the level of functional ambulation. Further work is needed to elucidate the contribution of biomechanical and neurologic parameters of hemiplegic gait impairments to turning capacity. PMID: 19893383 [PubMed - in process] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=2972223 Sun, 01 Nov 2009 00:00:00 +0100 2972223 http://www.medworm.com/index.php?rid=2911757&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19836283%26dopt%3DAbstract CONCLUSIONS: A tumor bed boost using the MammoSite breast brachytherapy applicator provides superior target coverage and delivers similar doses to the ipsilateral breast and lung compared to a boost delivered with electrons. More investigation into the role of balloon brachytherapy in the delivery of a breast boost is warranted. PMID: 19836283 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=2911757 Tue, 13 Oct 2009 23:00:00 +0100 2911757 http://www.medworm.com/index.php?rid=2863688&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19800827%26dopt%3DAbstract CONCLUSION: Our results demonstrate that the thyroid-mass based approach optimizes the treatment avoiding an un-justified excess or a not-effective too low activity without time and resources consuming. PMID: 19800827 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=2863688 Wed, 30 Sep 2009 23:00:00 +0100 2863688 http://www.medworm.com/index.php?rid=2863687&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19800828%26dopt%3DAbstract Authors: Xu Q, He Z, Fan J, Hamilton RJ, Chen Y, Ma CM, Xing L Current gated radiation therapy starts with simulation 4DCT images of a patient with lung cancer. We propose a method to confirm the phase of 4DCT for planning and setup position at the time of treatment. An intensity-based rigid algorithm was developed in this work to register an orthogonal set of on-board projection X-ray images with each phase of the 4DCT. Multiple DRRs for one of ten 4DCT phases are first generated and the correlation coefficient (CC) between the projection X-ray image and each DRR is computed. The maximum value of CC for the phase is found via a simulated annealing optimization process. The whole process repeats for all ten phases. The 4DCT phase that has the highest CC is identified as the breathing p... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2863687 Wed, 30 Sep 2009 23:00:00 +0100 2863687 http://www.medworm.com/index.php?rid=2863689&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19800276%26dopt%3DAbstract Authors: Caruana CJ, Wasilewska-Radwanska M, Aurengo A, Dendy PP, Karenauskaite V, Malisan MR, Meijer JH, Mihov D, Mornstein V, Rokita E, Vano E, Weckstrom M, Wucherer M Although biomedical physicists provide educational services to the healthcare professions in the majority of universities in Europe, their precise role with respect to the education of the healthcare professions has not been studied systematically. To address this issue we are conducting a research project to produce a strategic development model for the role using the well-established SWOT (Strengths, Weaknesses, Opportunities, Threats) methodology. SWOT based strategic planning is a two-step process: one first carries out a SWOT position audit and then uses the identified SWOT themes to construct the strategic develo... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2863689 Tue, 29 Sep 2009 23:00:00 +0100 2863689 http://www.medworm.com/index.php?rid=2847251&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19781969%26dopt%3DAbstract Authors: Zeinali A, Hashemi B, Akhlaghpoor S Noninvasive prediction of vertebral body strength under compressive loading condition is a valuable tool for the assessment of clinical fractures. This paper presents an effective specimen-specific approach for noninvasive prediction of human vertebral strength using a nonlinear finite element (FE) model and an image based parameter based on the quantitative computed tomography (QCT). Nine thoracolumbar vertebrae excised from three cadavers with an average age of 42 years old were used as the samples. The samples were scanned using the QCT. Then, a segmentation technique was performed on each QCT sectional image. The segmented images were then converted into three-dimensional FE models for linear and nonlinear analyses. A new material model ... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2847251 Tue, 22 Sep 2009 23:00:00 +0100 2847251 http://www.medworm.com/index.php?rid=2724845&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19695916%26dopt%3DAbstract We present a preliminary application of proper orthogonal decomposition (POD) to data sets coming from spatial and temporal evolution of renal scintigraphy. Renal functionalities or pathologies are hardly recognized from the raw scintigraphic images and their identifications could depend on the subjective point of view of the operator. The proposed technique is able to distinguish independent events starting from a more complex phenomenon. The spatio-temporal fields, representing the radiation emitted by the radiopharmaceutical technetium-99m with mercaptoacetiltriglicin (MAG3) within the kidney, have been analyzed for six randomly selected patients. In particular our study was performed on four patients affected by renal pathologies while two scintigraphies refer to healthy patients. Firs... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2724845 Mon, 17 Aug 2009 23:00:00 +0100 2724845 http://www.medworm.com/index.php?rid=2668476&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19648041%26dopt%3DAbstract Authors: Fan X, Mustafi D, Zamora M, River JN, Foxley S, Karczmar GS The purpose of this research was to test whether dynamic contrast enhanced MRI could assess the effect of green tea on the angiogenic properties of transplanted rodent tumors. Copenhagen rats bearing AT6.1 prostate tumors inoculated in the hind limbs were randomly assigned to cages in which they were allowed to only drink either plain water (control group) or water containing green tea extract (treated group). Assignments were made after a baseline MRI experiment (week 0) was performed on each rat at 4.7T. All the rats were subsequently imaged at day 7 (week 1) and day 14 (week 2) to follow tumor growth and vascular development. The two-compartment pharmacokinetic model was used to analyze the dynamic contrast Gd-DTPA... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2668476 Thu, 30 Jul 2009 23:00:00 +0100 2668476 http://www.medworm.com/index.php?rid=2627382&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19620015%26dopt%3DAbstract In this study the mean value of the percent of passing pixels within the region of interest under the criterion of 3% DD and 3mm DTA is 90.2+/-7.1% for head and neck cases and 92.2+/-5.8% for non-head and neck cases. If we choose the criteria of 3% DD and 3mm DTA then 96.3% head and neck plans have the percent of passing pixels>/=75% and 95.1% non-head and neck plans have the percent of passing pixels>/=80%. It is evident from the results of this study that the criterion of 5% DD and 3mm DTA with the percent of passing pixels>/=90 for non-head and neck cases while the percent of passing pixels>/=85 for head and neck cases endorse that a plan is good. The results of this study may be useful for other institutions which use verification software and EBT films for patient specific... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2627382 Fri, 17 Jul 2009 23:00:00 +0100 2627382 http://www.medworm.com/index.php?rid=2611520&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19604712%26dopt%3DAbstract Authors: Keshtkar A, Mesbahi A, H Rasta S, Keshtkar A A numerical technique, finite element analysis (FEA) was used to model the electrical properties, the bio impedance of the bladder tissue in order to predict the bladder cancer. This model results showed that the normal bladder tissue have significantly higher impedance than the malignant tissue that was in opposite with the impedance measurements or the experimental results. Therefore, this difference can be explained using the effects of inflammation, oedema on the urothelium and the property of the bladder as a distensible organ. Furthermore, the different current distributions inside the bladder tissue (in histological layers) in normal and malignant cases and finally different applied pressures over the bladder tissue can cause... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2611520 Sun, 12 Jul 2009 23:00:00 +0100 2611520 http://www.medworm.com/index.php?rid=2611519&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19604713%26dopt%3DAbstract This study was aimed at comparing the sensitivity and hot and cold contrasts obtained when imaging the PICKER thyroid phantom using gamma cameras fitted with either their ultra-high or high-resolution low-energy parallel hole collimator. Seventeen camera models from Elscint, General Electric, Siemens and Sopha Medical Vision were involved in the study for a total of 30 cameras and 52 camera heads. A single operator conducted the study in order to minimize the impact of human factors. The phantom contained about 74MBq (99m)Tc and was imaged at 10cm from the collimator face with the energy window that are recommended by the camera manufacturer. A total of 1 million counts were accumulated. Hot and cold contrasts were in mean of about 0.05 higher when using an ultra-high-resolution than when ... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2611519 Sun, 12 Jul 2009 23:00:00 +0100 2611519 http://www.medworm.com/index.php?rid=2548632&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19556686%26dopt%3DAbstract Authors: Pafundi D, Lee C, Watchman C, Bourke V, Aris J, Shagina N, Harrison J, Fell T, Bolch W Hybrid phantoms represent a third generation of computational models of human anatomy needed for dose assessment in both external and internal radiation exposures. Recently, we presented the first whole-body hybrid phantom of the ICRP reference newborn with a skeleton constructed from both non-uniform rational B-spline and polygon-mesh surfaces (Lee et al 2007 Phys. Med. Biol. 52 3309-33). The skeleton in that model included regions of cartilage and fibrous connective tissue, with the remainder given as a homogenous mixture of cortical and trabecular bone, active marrow and miscellaneous skeletal tissues. In the present study, we present a comprehensive skeletal tissue model of the ICRP refe... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2548632 Thu, 25 Jun 2009 23:00:00 +0100 2548632 http://www.medworm.com/index.php?rid=2548636&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19478373%26dopt%3DAbstract Authors: Seravalli E, de Boer MR, Geurink F, Huizenga J, Kreuger R, Schippers JM, van Eijk CW A two-dimensional position-sensitive dosimetry system based on a scintillating gas detector is being developed for pre-treatment verification of dose distributions in particle therapy. The dosimetry system consists of a chamber filled with an Ar/CF(4) scintillating gas mixture, inside which two gas electron multiplier (GEM) structures are mounted (Seravalli et al 2008b Med. Phys. Biol. 53 4651-65). Photons emitted by the excited Ar/CF(4) gas molecules during the gas multiplication in the GEM holes are detected by a mirror-lens-CCD camera system. The intensity distribution of the measured light spot is proportional to the 2D dose distribution. In this work, we report on the characterization of ... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2548636 Sat, 20 Jun 2009 23:00:00 +0100 2548636 http://www.medworm.com/index.php?rid=2548635&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19478380%26dopt%3DAbstract Authors: Kratt K, Scherrer A The formulation of intensity modulated radiation therapy (IMRT) planning aspects frequently uses the dose-volume histogram (DVH), whereas plan computations often happen in the more desirable convex IMRT optimization framework. Inspired by a recent publication of Zinchenko et al (2008 Phys. Med. Biol. 53 3231-50), this work addresses the integration of DVH-based planning aspects into this framework from a general point of view. It first provides the basic mathematical requirements on the evaluation functions in order to support such an incorporation. Then it introduces the condition number as a description for how precisely DVH-based planning aspects can be reformulated in terms of evaluation functions. Exemplary numerical studies for the generalized equival... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2548635 Sat, 20 Jun 2009 23:00:00 +0100 2548635 http://www.medworm.com/index.php?rid=2548638&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19443951%26dopt%3DAbstract Authors: Bohndiek SE, Royle GJ, Speller RD This paper describes the potential application of an active pixel sensor-based x-ray diffraction (APXRD) system in the field of breast cancer diagnosis. The design and initial testing of the system was reported previously (Bohndiek et al 2008b Phys. Med. Biol. 53 655-72). The system has potential both as a 'diffraction enhanced breast imager' (DEBI) and as a probe for quantitative analysis of breast biopsy samples. The resolution of the system in a DEBI arrangement is 1 mm and the contrast available using a material-specific x-ray diffraction image was found to be up to seven times greater than that of a transmission image. Scatter signatures from a series of biopsy-equivalent samples, ranging in composition from 100% fat to 100% fibrous tissu... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2548638 Sat, 06 Jun 2009 23:00:00 +0100 2548638 http://www.medworm.com/index.php?rid=2548637&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19446488%26dopt%3DAbstract Authors: Affatato S, Spinelli M, Zavalloni M PMID: 19446488 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=2548637 Tue, 12 May 2009 23:00:00 +0100 2548637 http://www.medworm.com/index.php?rid=2548639&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19419893%26dopt%3DAbstract In this study we have developed and tested a new semi-automated instrument ("CytoTest") designed for FNA which is intended to improve the efficacy of the technique by increasing the percentage of conclusive samples. A total of 443 consecutive aspiration procedures on palpable breast lesions were performed to compare this new "CytoTest" equipment with the standard protocol using the same type of needles. We conclude that by increasing the extent and frequency of the reciprocatory motions used by an experienced sampling operator as well as enhancing the ejection pressure, the cellular yield can be increased almost three folded compared to the standard protocol. For cases with high amounts of non-diagnostic material (such as blood or cystic fluid) which were discarded, up to four times more s... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2548639 Sun, 03 May 2009 23:00:00 +0100 2548639 http://www.medworm.com/index.php?rid=2548634&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19544793%26dopt%3DAbstract Authors: Engstrom E, Reiser I, Nishikawa R Burgess et al. [Med. Phys. 28, 419-437 (2001)] showed that the power spectrum of mammographic breast background follows a power law and that lesion detectability is affected by the power-law exponent beta which measures the amount of structure in the background. Following the study of Burgess et al., the authors measured and compared the power-law exponent of mammographic backgrounds in tomosynthesis projections and reconstructed slices to investigate the effect of tomosynthesis imaging on background structure. Our data set consisted of 55 patient cases. For each case, regions of interest (ROIs) were extracted from both projection images and reconstructed slices. The periodogram of each ROI was computed by taking the squared modulus of the Fou... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2548634 Thu, 30 Apr 2009 23:00:00 +0100 2548634 http://www.medworm.com/index.php?rid=2548633&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19544797%26dopt%3DAbstract Authors: Wang LL, La Russa DJ, Rogers DW In a previous study [Med. Phys. 35, 1747-1755 (2008)], the authors proposed two direct methods of calculating the replacement correction factors (P(repl) or P(cav)P(dis)) for ion chambers by Monte Carlo calculation. By "direct" we meant the stopping-power ratio evaluation is not necessary. The two methods were named as the high-density air (HDA) and low-density water (LDW) methods. Although the accuracy of these methods was briefly discussed, it turns out that the assumption made regarding the dose in an HDA slab as a function of slab thickness is not correct. This issue is reinvestigated in the current study, and the accuracy of the LDW method applied to ion chambers in a 60Co photon beam is also studied. It is found that the two direct methods... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2548633 Thu, 30 Apr 2009 23:00:00 +0100 2548633 http://www.medworm.com/index.php?rid=2328884&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19362032%26dopt%3DAbstract Authors: Eudaldo T, Olsen K A recently published EFOMP's survey on the status of Education and Training in Europe, has showed the important role played by the NMOs in the organisation of the Medical Physics education and training in most countries and their efforts to fulfil EFOMP recommendations. However, despite of this, there is still a wide variety of approaches within Europe, not only in the education and training programmes but also in professional practice. There is right now some European issues that can affect not only education and training but also the future of Medical Physics as a profession: 1. the harmonisation of the architecture of the European Higher Education System, arising from the "Bologna Declaration", for 2010, 2. the recently issued European directive: "Directi... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2328884 Wed, 08 Apr 2009 04:00:00 +0100 2328884 http://www.medworm.com/index.php?rid=2328885&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19356958%26dopt%3DAbstract In this study, thermoluminescent dosimeters based on alpha-Al(2)O(3):C were used to map the dose distribution to the extremities of physicians and paramedical personnel handling beta emitters. The results showed a strong inhomogeneous dose distribution between different phalanxes, fingers and hands of all the investigated subjects, without an indication of systematic trends in the dose patterns. Consequently, conventional dosimetric practices, based on the use of wrist or ring dosimeters, may be not suitable for providing reliable assessments of the inhomogeneous doses received at the fingertip. PMID: 19356958 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=2328885 Mon, 06 Apr 2009 04:00:00 +0100 2328885 http://www.medworm.com/index.php?rid=2328888&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19345598%26dopt%3DAbstract Authors: Kempe J, Brahme A The purpose of the present work is to develop analytical expressions for the depth variation of the fluence, planar fluence, the energy fluence, planar energy fluence, the mean energy and absorbed dose of primary ions and their associated fragments in tissue-like media with ranges of clinical interest. The analytical expressions of the primary ions and associated fragments take into account nuclear interactions, energy losses, range straggling and multiple scattering. The analytical models of the radiation field quantities were compared with the results of the modified Monte Carlo (MC) code SHIELD-HIT(+). The results show that the shape of the depth absorbed dose distribution of the primary particles is characterized by an increasingly steep exponential fluen... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2328888 Thu, 02 Apr 2009 04:00:00 +0100 2328888 http://www.medworm.com/index.php?rid=2328887&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19345599%26dopt%3DAbstract Authors: Stavreva N, Stavrev P, Fallone BG In this work two analytical methods are developed for computing the probability distribution of the number of surviving cells of a repopulating tumor during a fractionated external radio-treatment. Both methods are developed for the case of pure birth processes. They both allow the description of the tumor dynamics in case of cell radiosensitivity changing in time and for treatment schedules with variable dose per fraction and variable time intervals between fractions. The first method is based on a direct solution of the set of differential equations describing the tumor dynamics. The second method is based on the works of Hanin et al. [Hanin LG, Zaider M, Yakovlev AY. Distribution of the number of clonogens surviving fractionated radiotherap... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2328887 Thu, 02 Apr 2009 04:00:00 +0100 2328887 http://www.medworm.com/index.php?rid=2328886&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19345600%26dopt%3DAbstract We describe and test a simple, fast and accurate technique to estimate the couch and collimator angles required for a perfect geometric match using 3-D treatment planning software. This method requires no mathematical formulae and is verifiable relative to patient anatomy. An external skin contour is created on the axial slice at the match line and displayed with a 3-D representation. Using a beam's eye view (BEV) of a tangent field, small couch and collimator rotation adjustments are made sequentially until the contour edges are superimposed. The virtual external contour technique was easy to use, gave verification of the match in the BEV and yielded estimates of couch and collimator rotations very close to those calculated using published formulae. PMID: 19345600 [PubMed - as supplie... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2328886 Thu, 02 Apr 2009 04:00:00 +0100 2328886 http://www.medworm.com/index.php?rid=2328889&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19342258%26dopt%3DAbstract Authors: Habib B, Poumarede B, Tola F, Barthe J The aim of the present study is to demonstrate the potential of accelerated dose calculations, using the fast Monte Carlo (MC) code referred to as PENFAST, rather than the conventional MC code PENELOPE, without losing accuracy in the computed dose. For this purpose, experimental measurements of dose distributions in homogeneous and inhomogeneous phantoms were compared with simulated results using both PENELOPE and PENFAST. The simulations and experiments were performed using a Saturne 43 linac operated at 12 MV (photons), and at 18 MeV (electrons). Pre-calculated phase space files (PSFs) were used as input data to both the PENELOPE and PENFAST dose simulations. Since depth-dose and dose profile comparisons between simulations and measurem... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2328889 Tue, 31 Mar 2009 04:00:00 +0100 2328889 http://www.medworm.com/index.php?rid=2284132&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19299178%26dopt%3DAbstract We present a simple technique based on the omni-wedge concept which uses superimposed fields, orthogonally wedged, to improve target-volumes homogeneity in head and neck tumour irradiation. The routine implementation of this technique is straightforward and easy to achieve with standard radiotherapy equipment and treatment planning software. Our five-year experience in the clinical implementation of this technique is presented. PMID: 19299178 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=2284132 Tue, 17 Mar 2009 04:00:00 +0100 2284132 http://www.medworm.com/index.php?rid=2274492&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19286407%26dopt%3DAbstract CONCLUSION: The application of the presented methodology revealed cost-effectiveness relationships in tested technical procedures. PMID: 19286407 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=2274492 Sat, 14 Mar 2009 04:00:00 +0100 2274492 http://www.medworm.com/index.php?rid=2211362&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19231267%26dopt%3DAbstract CONCLUSION: The choice of the acquisition parameter is essential for the accurate portal dose imaging. PMID: 19231267 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=2211362 Thu, 19 Feb 2009 05:00:00 +0100 2211362 http://www.medworm.com/index.php?rid=2205379&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19229094%26dopt%3DAbstract Authors: Ross CK The authors of a recent paper (McNiven et al 2008 Phys. Med. Biol. 53 5029-43) measured the volume of a particular type of a small ionization chamber using CT images. Using four Exradin A1SL chambers, they find that the volume measured using CT imaging is, on average, 4.3% larger than the value derived from the chamber calibration coefficient. Although they point out that the effective chamber volume is defined by electric field lines between the collector and the chamber body, they do not estimate how the mechanical volume might differ from the effective volume. We have used a commercial software package to calculate the electric field in the cavity and we show that the field lines define a volume that is about 11% smaller than the mechanical volume. We also show that... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2205379 Thu, 19 Feb 2009 05:00:00 +0100 2205379 http://www.medworm.com/index.php?rid=2205378&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19229097%26dopt%3DAbstract Authors: McNiven AL, Umoh J, Kron T, Holdsworth DW, Battista JJ Air ionization chamber dosimetry plays a crucial role in international dose calibration for the radiotherapy clinical environment. Micro-CT images of ion chambers can play an important role in quality assurance of these devices by detecting internal geometry, materials and defects non-invasively, as we demonstrated (McNiven et al 2008 Phys. Med. Biol. 53 5029-43). We also suggested that electric-field simulation based upon these accurate chamber-specific 3D images rather than manufacturer blueprints could be valuable in assessing ionometric sensitivity. As recently performed by Ross et al these electric field simulations play a vital role in understanding key components that contribute to the chamber sensitive volume and i... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2205378 Thu, 19 Feb 2009 05:00:00 +0100 2205378 http://www.medworm.com/index.php?rid=2205377&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19229100%26dopt%3DAbstract In this study, EGSnrc Monte Carlo simulation codes are used to simulate Johansson et al's experimental procedures for determining P(repl) values. The simulation results agree well with the measurements if the chamber responses versus depth are normalized at d(max) as was apparently done in the experiments as it was believed that the chambers of different radii gave the same maximum reading at the respective d(max). However, if the chamber responses are not normalized, then the simulated experimental results lead to a result which agrees well with the P(repl) values calculated by the standard Monte Carlo methods. This demonstrates that the normalization procedure used in the experiments is incorrect as is based on an incorrect assumption, and thus the interpretation of Johansson et al's exp... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2205377 Thu, 19 Feb 2009 05:00:00 +0100 2205377 http://www.medworm.com/index.php?rid=2200896&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19226647%26dopt%3DAbstract In this study, multivariate analyses of craniometric data support Sauer's hypothesis that there are morphological differences between American whites and blacks. We also confirm significant geographic patterning in human variation but also find differences among groups within continents. As a result, if biological races are defined by uniqueness, then there are a very large number of biological races that can be defined, contradicting the classic biological race concept of physical anthropology. Further, our results show that humans can be accurately classified into geographic origin using craniometrics even though there is overlap among groups. Am J Phys Anthropol 2009. (c) 2009 Wiley-Liss, Inc. PMID: 19226647 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=2200896 Wed, 18 Feb 2009 05:00:00 +0100 2200896 http://www.medworm.com/index.php?rid=2188229&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19213586%26dopt%3DAbstract Authors: van Langen H, Castelijn T In many X-ray clinics, the traditional photographic film has been replaced by an imaging plate (IP). The IP is re-usable and the purpose of this study was to test if image deterioration occurred after successive uses of the IP. The emphasis is placed on the efficiency of image formation and on image uniformity. In a cross-sectional study, 21 clinically used IPs were exposed with a standardized phantom imaging protocol. These IPs were in clinical use between one month and two years and the IPs were exposed between 191 and 3787 times. After digitizing, the mean pixel value (MPV) in a predefined image area was determined. The relation between MPV and IP uses was assessed. In a second experiment, image uniformity of 30 other clinically used IPs was visual... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2188229 Tue, 10 Feb 2009 05:00:00 +0100 2188229 http://www.medworm.com/index.php?rid=2183098&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19208489%26dopt%3DAbstract Authors: Shcherbinin S, Celler A, Trummer M, Humphries T Dual-isotope SPECT (DI-SPECT) studies offer significant advantages over sequential scans, foremost among them faster acquisition and perfect image registration. However, reconstructed images may be affected by substantial cross-talk contamination rendering them inadequate for diagnosis. This effect is especially strong for isotopes with close photopeak energies, such as (99m)Tc (140keV) and (123)I (159keV). In this paper we present an iterative DI-SPECT reconstruction method which includes accurate, analytically computed scatter corrections provided by the APD (analytical photon distribution) algorithm. This algorithm calculates first and second order Compton scatter (based on the Klein-Nishina formula) and first order Rayleigh s... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2183098 Sat, 07 Feb 2009 05:00:00 +0100 2183098 http://www.medworm.com/index.php?rid=2138094&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19167918%26dopt%3DAbstract Authors: Topaltzikis T, Rountas C, Fezoulidis I, Kappas C, Theodorou K The Euratom directive 97/43 recommends the use of patient dose surveys in diagnostic radiology and the establishment of diagnostic reference dose levels (DRLs). The aims of this study are to perform measurements of the entrance surface dose (ESD) during diagnostic digital subtraction angiography (DSA) of the renal and carotid arteries using thermoluminescence dosemeters (TLDs), extraction of local DRLs, and calculation of the effective dose. Dose measurement for the staff was also performed. Dose measurements were performed on 48 participating patients. The mean effective dose was calculated to be 15.9mSv and 8.9mSv, for the renal and carotid DSA, respectively. The effective dose of the radiologist was calculated to... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2138094 Thu, 22 Jan 2009 05:00:00 +0100 2138094 http://www.medworm.com/index.php?rid=2061544&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19101188%26dopt%3DAbstract Authors: Conti M After a brief review of the history of time-of-flight (TOF) positron emission tomography (PET) instrumentation from the 1980s to present, the principles of TOF PET are introduced, the concept of time resolution and its effect on TOF gain in signal-to-noise ratio (SNR) are discussed. The factors influencing the time resolution of a TOF PET scanner are presented, with focus on the intrinsic properties of scintillators of particular interest for TOF PET. Finally, some open issues, challenges and achievements of today's TOF PET reconstruction are reviewed: the structure of the data organization, the choice of analytical or iterative method, the recent experimental assessment of TOF image quality, and the most promising applications of TOF PET. PMID: 19101188 [PubMed - ... Physica Medica journals http://www.medworm.com/rss/comments.php?id=2061544 Thu, 18 Dec 2008 05:00:00 +0100 2061544 http://www.medworm.com/index.php?rid=2027772&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19059797%26dopt%3DAbstract Authors: Christofides S This EFOMP Policy Statement outlines the way in which a Safety and Quality Management System can be developed for Medical Physics Departments. The Policy Statement can help Medical Physicists to eliminate or at least minimize accidents or incidences due to improper use or application of medical technology on one hand and on the other to guarantee a safe, effective and efficient usage of new highly complicated and sophisticated technologies and procedures. PMID: 19059797 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=2027772 Fri, 05 Dec 2008 05:00:00 +0100 2027772 http://www.medworm.com/index.php?rid=2011531&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19045884%26dopt%3DAbstract We report on the characterization of three Fuji BAS IP responses to x-rays using a radioactive source, and discrete x-ray line energies generated by the Excalibur soft x-ray facility and the Defense Radiological Standards Centre filter-fluorescer hard x-ray system at AWE. PMID: 19045884 [PubMed - in process] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=2011531 Sat, 01 Nov 2008 04:00:00 +0100 2011531 http://www.medworm.com/index.php?rid=1924703&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18971766%26dopt%3DAbstract CONCLUSIONS:: RTW was successful in 33% of the subjects. Wheelchair capacity was independently related to RTW. Therefore, it is recommended to train wheelchair capacity in the context of RTW. PMID: 18971766 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=1924703 Sat, 25 Oct 2008 04:00:00 +0100 1924703 http://www.medworm.com/index.php?rid=1924702&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18971767%26dopt%3DAbstract CONCLUSIONS:: These results suggest that short periods of low-intensity, low-stimulation frequency (20 Hz) ES of muscle during periods of inactivity could maintain changes in both morphologic and histologic properties of the slow-twitch muscle fibers (soleus). Short periods of low-intensity, high-stimulation frequency (30 Hz) ES of muscle during periods of inactivity could maintain changes in both morphologic and histologic properties of the fast-twitch muscle fibers (extensor digitorum longus). PMID: 18971767 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=1924702 Sat, 25 Oct 2008 04:00:00 +0100 1924702 http://www.medworm.com/index.php?rid=1924701&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18971768%26dopt%3DAbstract CONCLUSIONS:: A short hypnotic induction seems to reduce worst pain during electromyography. PMID: 18971768 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=1924701 Sat, 25 Oct 2008 04:00:00 +0100 1924701 http://www.medworm.com/index.php?rid=1924700&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18971769%26dopt%3DAbstract CONCLUSIONS:: IGF-I serum levels were significantly associated with ability to function after hip fracture in women. PMID: 18971769 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=1924700 Sat, 25 Oct 2008 04:00:00 +0100 1924700 http://www.medworm.com/index.php?rid=1924699&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18971770%26dopt%3DAbstract CONCLUSIONS:: Impaired muscle strength was explained by reduced muscle mass, but it did not account for abnormal muscle endurance. The latter seems associated to impaired O2 transport/O2 utilization, resulting in altered muscle bioenergetics. PMID: 18971770 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=1924699 Sat, 25 Oct 2008 04:00:00 +0100 1924699 http://www.medworm.com/index.php?rid=1924698&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18971771%26dopt%3DAbstract Authors: Macdonald B, Kirby RL, Smith C, Macleod DA, Webber A MacDonald B, Kirby RL, Smith C, MacLeod DA, Webber A: Sitting pressure in the tilted position: Manual tilt-in-space wheelchair vs. manual wheelchair with a new rear antitip device. Am J Phys Med Rehabil 2008;87:***.To test the hypothesis that, in comparison with a heavier, larger and more expensive manual tilt-in-space wheelchair, a lightweight manual wheelchair equipped with new rear antitip devices provides comparable mean sitting pressures in the tilted position, each of eight able-bodied participants sat for 8 mins in each wheelchair, upright, and tilted back (38-39 degrees). The mean (+/-SD) sitting pressures (of all active sensors in a force-sensing array) at the eighth minute in the upright and tilted positions with t... Physica Medica journals http://www.medworm.com/rss/comments.php?id=1924698 Sat, 25 Oct 2008 04:00:00 +0100 1924698 http://www.medworm.com/index.php?rid=1924697&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18971772%26dopt%3DAbstract We present the previously unreported hazard of creating pressure ulceration in a susceptible host by the improper use of a silicone prosthetic liner. An 80-yr-old man sustained a recent transtibial amputation for peripheral vascular disease. His comorbidities included vascular cognitive impairment, type 2 diabetes mellitus, coronary artery disease, anemia of chronic disease, postherpetic neuralgia, and pruritus of uncertain origin. When not using his transtibial prosthesis, he found his 1.5-mm thick silicone liner (ICEROSS) more comfortable to wear than his stump shrinker and thermoplastic protector. Moreover, he repeatedly wore his liner rolled partway down his stump to allow him to scratch pruritic skin. A horizontal, linear, stage 2 ulcer developed on the residual limb under the upper e... Physica Medica journals http://www.medworm.com/rss/comments.php?id=1924697 Sat, 25 Oct 2008 04:00:00 +0100 1924697 http://www.medworm.com/index.php?rid=1924696&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18971773%26dopt%3DAbstract In conclusion, we demonstrated that the integrity of CST had been spared in the anterior portion of the medulla infarct by using diffusion tensor tractography and transcranial magnetic stimulation. PMID: 18971773 [PubMed - as supplied by publisher] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=1924696 Sat, 25 Oct 2008 04:00:00 +0100 1924696 http://www.medworm.com/index.php?rid=1901961&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18941280%26dopt%3DAbstract Authors: Hoffmann AL, den Hertog D, Siem AY, Kaanders JH, Huizenga H Finding fluence maps for intensity-modulated radiation therapy (IMRT) can be formulated as a multi-criteria optimization problem for which Pareto optimal treatment plans exist. To account for the dose-per-fraction effect of fractionated IMRT, it is desirable to exploit radiobiological treatment plan evaluation criteria based on the linear-quadratic (LQ) cell survival model as a means to balance the radiation benefits and risks in terms of biologic response. Unfortunately, the LQ-model-based radiobiological criteria are nonconvex functions, which make the optimization problem hard to solve. We apply the framework proposed by Romeijn et al (2004 Phys. Med. Biol. 49 1991-2013) to find transformations of LQ-model-based ra... Physica Medica journals http://www.medworm.com/rss/comments.php?id=1901961 Tue, 21 Oct 2008 04:00:00 +0100 1901961 http://www.medworm.com/index.php?rid=1859765&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18838356%26dopt%3DAbstract Authors: Ertel D, Pflederer T, Achenbach S, Kalender WA The reconstruction phase providing optimal image quality in coronary CT angiography is dependent on the heart rate but additionally displays substantial patient-dependent variation. The purpose of this study was to provide online identification of the patient-specific optimal reconstruction phase during CT coronary angiography data acquisition and to allow adaptation of tube current modulation for the individual patient. A raw data-based cardiac motion signal (kymogram) was used for the detection of the optimal reconstruction phase. The individual motion curve of each patient was correlated with dedicated template curves to reduce signal noise. Data sets of 90 consecutive patients were used for validation purposes. The reliability... Physica Medica journals http://www.medworm.com/rss/comments.php?id=1859765 Tue, 30 Sep 2008 04:00:00 +0100 1859765 http://www.medworm.com/index.php?rid=1755206&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18760736%26dopt%3DAbstract Authors: Nüsslin F, Hendee W PMID: 18760736 [PubMed - in process] (Source: Physica Medica) Physica Medica journals http://www.medworm.com/rss/comments.php?id=1755206 Mon, 01 Sep 2008 04:00:00 +0100 1755206 http://www.medworm.com/index.php?rid=1746906&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18722148%26dopt%3DAbstract Authors: Edimo P, Clermont C, Kwato MG, Vynckier S In the present work, Monte Carlo (MC) models of electron beams (energies 4, 12 and 18MeV) from an Elekta SL25 medical linear accelerator were simulated using EGSnrc/BEAMnrc user code. The calculated dose distributions were benchmarked by comparison with measurements made in a water phantom for a wide range of open field sizes and insert combinations, at a single source-to-surface distance (SSD) of 100cm. These BEAMnrc models were used to evaluate the accuracy of a commercial MC dose calculation engine for electron beam treatment planning (Oncentra MasterPlan Treament Planning System (OMTPS) version 1.4, Nucletron) for two energies, 4 and 12MeV. Output factors were furthermore measured in the water phantom and compared to BEAMnrc and OM... Physica Medica journals http://www.medworm.com/rss/comments.php?id=1746906 Wed, 20 Aug 2008 04:00:00 +0100 1746906 http://www.medworm.com/index.php?rid=1701288&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18694653%26dopt%3DAbstract Authors: Mumot M, Mytsin GV, Molokanov AG, Malicki J We wanted to verify the response of radiochromic films in a 175MeV clinical proton beam used at the Joint Institute for Nuclear Research in Dubna against doses measured using semiconductor detectors and compare the results with published data from other centres. Radiochromic films (RCFs) MD-55 and a Vidar VXR-16 scanner were used. The films were irradiated in an unmodulated proton beam and with a beam modulated with a bolus and a ridge filter. Obtained dose distributions were compared with dose distributions measured with a Si-semiconductor detector. For the unmodulated beam the difference between the RCF and the semiconductor detector was 12% in the Bragg peak top. For the modulated beam the difference inside the spread-out Bragg pe... Physica Medica journals http://www.medworm.com/rss/comments.php?id=1701288 Sat, 09 Aug 2008 04:00:00 +0100 1701288 http://www.medworm.com/index.php?rid=1596816&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18602852%26dopt%3DAbstract Authors: Zhou SA, Brahme A A significant improvement over conventional attenuation-based X-ray imaging, which lacks contrast in small objects and soft biological tissues, is obtained by introducing phase-contrast imaging. As recently demonstrated, phase-contrast imaging is characterized by its extraordinary image quality, greatly enhanced contrast, and good soft tissue discrimination with very high spatial resolution down to the micron and even the sub-micron region. The rapid development of compact X-ray sources of high brightness, tuneability, and monochromaticity as well as high-resolution X-ray detectors with high quantum efficiency and improved computational methods is stimulating the development of a new generation of X-ray imaging systems for medical applications. The present pa... Physica Medica journals http://www.medworm.com/rss/comments.php?id=1596816 Thu, 03 Jul 2008 04:00:00 +0100 1596816 http://www.medworm.com/index.php?rid=1596815&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18602853%26dopt%3DAbstract Authors: Ito S, Saze T, Ariga E, Deji S, Hirota M, Nishizawa K A system for taking static thyroid (99m)Tc images was devised by using multiple imaging plates (IPs) and a low-energy high resolution collimator. System spatial resolution of the IP systems and the gamma camera was determined by referring to standards set by the National Electrical Manufacturers Association. Sensitivity was represented by using lower detection limits (LDLs). The sensitivity and resolution of IP systems using 16 IP probes connecting two collimators and 9 IPs were determined by using a 20ml thyroid phantom, and compared with the sensitivity of gamma cameras. The sensitivity of the IP systems increased in proportion to the number of IPs. The sensitivity and resolution of a probe using 6 IPs and a high resoluti... Physica Medica journals http://www.medworm.com/rss/comments.php?id=1596815 Thu, 03 Jul 2008 04:00:00 +0100 1596815 http://www.medworm.com/index.php?rid=1596814&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18602854%26dopt%3DAbstract We describe the implementation in several Italian hospitals of a computer aided detection (CAD) system, named GPCALMA (grid platform for a computer aided library in mammography), for the automatic search of lesions in X-ray mammographies. GPCALMA has been under development since 1999 by a community of physicists of the Italian National Institute for Nuclear Physics (INFN) in collaboration with radiologists. This CAD system was tested as a support to radiologists in reading mammographies. The main system components are: (i) the algorithms implemented for the analysis of digitized mammograms to recognize suspicious lesions, (ii) the database of digitized mammographic images, and (iii) the PC-based digitization and analysis workstation and its user interface. The distributed nature of data an... Physica Medica journals http://www.medworm.com/rss/comments.php?id=1596814 Thu, 03 Jul 2008 04:00:00 +0100 1596814 http://www.medworm.com/index.php?rid=1564167&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18590976%26dopt%3DAbstract In this study, an effort has been made to see the applicability of biological dosimetry using micronuclei assay for dose estimation in therapeutic irradiation of cancer patients in acute high dose partial body irradiation. Dose estimation in partial body irradiations was done on the basis of Dolphin's contaminated Poisson method, using the in vitro dose response calibration curve. The equivalent whole body dose and the dose to the irradiated part of the body were estimated to be 1.8+/-0.1Gy and 6.4+/-0.3Gy, respectively. The estimated percentage of irradiated blood and the fraction of cells exposed were 41.5+/-1.6% and 10.4+/-0.8%, respectively. The estimated fraction of irradiated cells was comparable with the actual volume of irradiation. PMID: 18590976 [PubMed - as supplied by publi... Physica Medica journals http://www.medworm.com/rss/comments.php?id=1564167 Sat, 28 Jun 2008 04:00:00 +0100 1564167 http://www.medworm.com/index.php?rid=1564166&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18590977%26dopt%3DAbstract Authors: Mady MM, Ghannam MM, Khalil WA, Müller R, Fahr A It is necessary to understand liposomal uptake mechanisms and intracellular distribution in order to design more efficient gene (drug) carrier systems. Until now, a few studies have been carried out using confocal laser scanning microscopy (CLSM) to investigate the cellular uptake and transfection mediated with liposomes. So, by CLSM, we demonstrated that artificial virus-like envelope (AVE) vesicles labeled with rhodamine-PE (Rh-PE), carbocyanine (DiI) and carboxyfluorescein (CF) were investigated into the cytoplasm of two human cell lines, Mewo (human melanoma cell line) and HepG2 (human hepatoma cell line) cells grown in DMEM medium supplemented with different percentages (0%, 30%, and 100%) fetal calf serum (FCS). The l... Physica Medica journals http://www.medworm.com/rss/comments.php?id=1564166 Sat, 28 Jun 2008 04:00:00 +0100 1564166 http://www.medworm.com/index.php?rid=1543916&cid=s_35851_75_f&fid=35851&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18571964%26dopt%3DAbstract Authors: Bilge H, Cakir A, Okutan M, Acar H The aim of this study was to determine the surface doses using GafChromic EBT films and compare them with plane-parallel ionization chamber measurements for 6 and 18MV high energy photon beams. The measurements were made in a water equivalent solid phantom in the build-up region of the 6 and 18MV photon beams at 100cm SSD for various field sizes. Markus type plane-parallel ion chamber with fixed-separation between collecting electrodes was used to measure the percent depth doses. GafChromic EBT film measurements were performed both on the phantom surface and maximum dose depth at the same geometry with ion chamber measurements. The surface doses found using GafChromic EBT film were 15%, 20%, 29%and 39%+/-2% (1SD) for 6MV photons, 6%, 11%, 23%... Physica Medica journals http://www.medworm.com/rss/comments.php?id=1543916 Thu, 19 Jun 2008 04:00:00 +0100 1543916