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Experiri: building the pathway to best recognize those who strive to master the art of the practice of medicine.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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)
Source: Physica Medica - November 1, 2009 Category: Physics Authors: Weiss KB Tags: Am J Phys Med Rehabil Source Type: journals

Turning capacity in ambulatory individuals poststroke.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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)
Source: Physica Medica - November 1, 2009 Category: Physics Authors: Lam T, Luttmann K Tags: Am J Phys Med Rehabil Source Type: journals

A dosimetric analysis comparing electron beam with the MammoSite brachytherapy applicator for intact breast boost.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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)
Source: Physica Medica - October 13, 2009 Category: Physics Authors: Shah AP, Strauss JB, Kirk MC, Chen SS, Dickler A Tags: Phys Med Source Type: journals

Possibility of limiting the un-justified irradiation in (131)I therapy of Graves' disease: A thyroid mass-reduction based method for the optimum activity calculation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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)
Source: Physica Medica - September 30, 2009 Category: Physics Authors: Traino AC, Grosso M, Mariani G Tags: Phys Med Source Type: journals

Registration of on-board X-ray images with 4DCT: A proposed method of phase and setup verification for gated radiotherapy.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 ...
Source: Physica Medica - September 30, 2009 Category: Physics Authors: Xu Q, He Z, Fan J, Hamilton RJ, Chen Y, Ma CM, Xing L Tags: Phys Med Source Type: journals

A comprehensive SWOT audit of the role of the biomedical physicist in the education of healthcare professionals in Europe.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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...
Source: Physica Medica - September 29, 2009 Category: Physics 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 Tags: Phys Med Source Type: journals

Noninvasive prediction of vertebral body compressive strength using nonlinear finite element method and an image based technique.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 s...
Source: Physica Medica - September 22, 2009 Category: Physics Authors: Zeinali A, Hashemi B, Akhlaghpoor S Tags: Phys Med Source Type: journals

Proper orthogonal decomposition analysis of spatio-temporal behavior of renal scintigraphies.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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...
Source: Physica Medica - August 17, 2009 Category: Physics Authors: Veltri P, Vecchio A, Carbone V Tags: Phys Med Source Type: journals

Can DCEMRI assess the effect of green tea on the angiogenic properties of rodent prostate tumors?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 de...
Source: Physica Medica - July 30, 2009 Category: Physics Authors: Fan X, Mustafi D, Zamora M, River JN, Foxley S, Karczmar GS Tags: Phys Med Source Type: journals

Evaluation criteria for film based intensity modulated radiation therapy quality assurance.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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...
Source: Physica Medica - July 17, 2009 Category: Physics Authors: Anjum MN, Parker W, Ruo R, Afzal M Tags: Phys Med Source Type: journals

The feasibility of computational modelling technique to detect the bladder cancer.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 histolog...
Source: Physica Medica - July 12, 2009 Category: Physics Authors: Keshtkar A, Mesbahi A, H Rasta S, Keshtkar A Tags: Phys Med Source Type: journals

Hot and cold contrasts in high-resolution Tc-99m planar scintigraphy: A survey of fifty-two camera heads using the PICKER thyroid phantom.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 ...
Source: Physica Medica - July 12, 2009 Category: Physics Authors: Seret A Tags: Phys Med Source Type: journals

An image-based skeletal tissue model for the ICRP reference newborn.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 presen...
Source: Physica Medica - June 25, 2009 Category: Physics Authors: Pafundi D, Lee C, Watchman C, Bourke V, Aris J, Shagina N, Harrison J, Fell T, Bolch W Tags: Phys Med Biol Source Type: journals

2D dosimetry in a proton beam with a scintillating GEM detector.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 t...
Source: Physica Medica - June 20, 2009 Category: Physics Authors: Seravalli E, de Boer MR, Geurink F, Huizenga J, Kreuger R, Schippers JM, van Eijk CW Tags: Phys Med Biol Source Type: journals

The integration of DVH-based planning aspects into a convex intensity modulated radiation therapy optimization framework.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 preci...
Source: Physica Medica - June 20, 2009 Category: Physics Authors: Kratt K, Scherrer A Tags: Phys Med Biol Source Type: journals

An active pixel sensor x-ray diffraction (APXRD) system for breast cancer diagnosis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 i...
Source: Physica Medica - June 6, 2009 Category: Physics Authors: Bohndiek SE, Royle GJ, Speller RD Tags: Phys Med Biol Source Type: journals

Comments on: Tribology and total hip joint replacement: Current concepts in mechanical simulation, Med. Eng. Phys. 30 (2008) 1305-1317, Affatato S. et al.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 19446488 [PubMed - as supplied by publisher] (Source: Physica Medica)
Source: Physica Medica - May 12, 2009 Category: Physics Authors: Affatato S, Spinelli M, Zavalloni M Tags: Med Eng Phys Source Type: journals

A new semi-automated instrument to improve the fine needle aspiration procedure during breast lesion cell sampling.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 fold...
Source: Physica Medica - May 3, 2009 Category: Physics Authors: Wiksell H, Ekstrand V, Wadström C, Auer G Tags: Phys Med Source Type: journals

Comparison of power spectra for tomosynthesis projections and reconstructed images.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 bot...
Source: Physica Medica - April 30, 2009 Category: Physics Authors: Engstrom E, Reiser I, Nishikawa R Tags: Med Phys Source Type: journals

Systematic uncertainties in the Monte Carlo calculation of ion chamber replacement correction factors.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 ...
Source: Physica Medica - April 30, 2009 Category: Physics Authors: Wang LL, La Russa DJ, Rogers DW Tags: Med Phys Source Type: journals

The European Federation of Organisations for Medical Physics. Policy Statement No. 12: The present status of Medical Physics Education and Training in Europe. New perspectives and EFOMP recommendations.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 ...
Source: Physica Medica - April 8, 2009 Category: Physics Authors: Eudaldo T, Olsen K Tags: Phys Med Source Type: journals

Spatial distribution of beta extremity doses in nuclear medicine: A feasibility study with thin alpha-Al(2)O(3):C TLDs.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 ...
Source: Physica Medica - April 6, 2009 Category: Physics Authors: Mancosu P, Cantone MC, Veronese I, Giussani A Tags: Phys Med Source Type: journals

Analytical theory for the fluence, planar fluence, energy fluence, planar energy fluence and absorbed dose of primary particles and their fragments in broad therapeutic light ion beams.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 s...
Source: Physica Medica - April 2, 2009 Category: Physics Authors: Kempe J, Brahme A Tags: Phys Med Source Type: journals

Probability dynamics of a repopulating tumor in case of fractionated external radiotherapy.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 wor...
Source: Physica Medica - April 2, 2009 Category: Physics Authors: Stavreva N, Stavrev P, Fallone BG Tags: Phys Med Source Type: journals

Technical note: A virtual matching technique for three-field breast irradiation using 3-D planning.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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...
Source: Physica Medica - April 2, 2009 Category: Physics Authors: Strauss JB, Kirk MC, Chen SS, Shah AP, Gielda BT, Chu JC, Turian JV, Dickler A Tags: Phys Med Source Type: journals

Evaluation of PENFAST - A fast Monte Carlo code for dose calculations in photon and electron radiotherapy treatment planning.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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...
Source: Physica Medica - March 31, 2009 Category: Physics Authors: Habib B, Poumarede B, Tola F, Barthe J Tags: Phys Med Source Type: journals

Omni-wedge technique for increased dose homogeneity in head and neck radiotherapy.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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)
Source: Physica Medica - March 17, 2009 Category: Physics Authors: Vinagre FL, Simões PC, Rachinhas PJ Tags: Phys Med Source Type: journals

Cost-effectiveness of the modifications in the quality assurance system in radiotherapy in the example of in-vivo dosimetry.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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)
Source: Physica Medica - March 14, 2009 Category: Physics Authors: Malicki J, Litoborski M, Bogusz-Czerniewicz M, Swiezewski A Tags: Phys Med Source Type: journals

Role of "the frame cycle time" in portal dose imaging using an aS500-II EPID.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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)
Source: Physica Medica - February 19, 2009 Category: Physics Authors: Al Kattar Elbalaa Z, Foulquier JN, Orthuon A, Elbalaa H, Touboul E Tags: Phys Med Source Type: journals

Comments on 'Ionization chamber volume determination and quality assurance using micro-CT imaging'Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 ...
Source: Physica Medica - February 19, 2009 Category: Physics Authors: Ross CK Tags: Phys Med Biol Source Type: journals

Response to 'Comments on 'Ionization chamber volume determination and quality assurance using micro-CT imaging''Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 simulatio...
Source: Physica Medica - February 19, 2009 Category: Physics Authors: McNiven AL, Umoh J, Kron T, Holdsworth DW, Battista JJ Tags: Phys Med Biol Source Type: journals

The replacement correction factors for cylindrical chambers in high-energy photon beams.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 demon...
Source: Physica Medica - February 19, 2009 Category: Physics Authors: Wang LL, Rogers DW Tags: Phys Med Biol Source Type: journals

Understanding race and human variation: Why forensic anthropologists are good at identifying race.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 i...
Source: Physica Medica - February 18, 2009 Category: Physics Authors: Ousley S, Jantz R, Freid D Tags: Am J Phys Anthropol Source Type: journals

Durability of imaging plates in clinical use.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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....
Source: Physica Medica - February 10, 2009 Category: Physics Authors: van Langen H, Castelijn T Tags: Phys Med Source Type: journals

An APD-based iterative reconstruction method for simultaneous technetium-99m/iodine-123 SPECT imaging.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 ...
Source: Physica Medica - February 7, 2009 Category: Physics Authors: Shcherbinin S, Celler A, Trummer M, Humphries T Tags: Phys Med Source Type: journals

In vivo dosimetry during DSA of the carotid and renal arteries. Deriviation of local DRLs.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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, f...
Source: Physica Medica - January 22, 2009 Category: Physics Authors: Topaltzikis T, Rountas C, Fezoulidis I, Kappas C, Theodorou K Tags: Phys Med Source Type: journals

State of the art and challenges of time-of-flight PET.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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...
Source: Physica Medica - December 18, 2008 Category: Physics Authors: Conti M Tags: Phys Med Source Type: journals

The European federation of organisations for medical physics policy statement No. 13: Recommended guidelines on the development of safety and quality management systems for medical physics departments.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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)
Source: Physica Medica - December 5, 2008 Category: Physics Authors: Christofides S Tags: Phys Med Source Type: journals

Evaluation of the sensitivity and fading characteristics of an image plate system for x-ray diagnostics.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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)
Source: Physica Medica - November 1, 2008 Category: Physics Authors: Meadowcroft AL, Bentley CD, Stott EN Tags: Rev Sci Instrum Source Type: journals

Return to Work After Spinal Cord Injury: Is It Related to Wheelchair Capacity at Discharge from Clinical Rehabilitation?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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)
Source: Physica Medica - October 25, 2008 Category: Physics Authors: van Velzen JM, de Groot S, Post MW, Slootman JH, van Bennekom CA, van der Woude LH Tags: Am J Phys Med Rehabil Source Type: journals

Effect of Electrical Stimulation to Prevent Muscle Atrophy on Morphologic and Histologic Properties of Hindlimb Suspended Rat Hindlimb Muscles.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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)
Source: Physica Medica - October 25, 2008 Category: Physics Authors: Onuma B, Naoki K, Kiyoji M, Shinji M Tags: Am J Phys Med Rehabil Source Type: journals

The Feasibility of Hypnotic Analgesia in Ameliorating Pain and Anxiety Among Adults Undergoing Needle Electromyography.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
CONCLUSIONS:: A short hypnotic induction seems to reduce worst pain during electromyography. PMID: 18971768 [PubMed - as supplied by publisher] (Source: Physica Medica)
Source: Physica Medica - October 25, 2008 Category: Physics Authors: Slack D, Nelson L, Patterson D, Burns S, Hakimi K, Robinson L Tags: Am J Phys Med Rehabil Source Type: journals

Serum Levels of Insulin-Like Growth Factor-I Are Positively Associated with Functional Outcome After Hip Fracture in Elderly Women.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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)
Source: Physica Medica - October 25, 2008 Category: Physics Authors: Monaco MD, Vallero F, Monaco RD, Tappero R, Cavanna A Tags: Am J Phys Med Rehabil Source Type: journals

Clinical Assessment of Peripheral Muscle Function in Patients with Chronic Obstructive Pulmonary Disease.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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)
Source: Physica Medica - October 25, 2008 Category: Physics Authors: Vilaro J, Rabinovich R, Gonzalez-Desuso JM, Troosters T, Rodríguez D, Barberà JA, Roca J Tags: Am J Phys Med Rehabil Source Type: journals

Sitting Pressure in the Tilted Position: Manual Tilt-in-Space Wheelchair vs. Manual Wheelchair with a New Rear Antitip Device.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 ...
Source: Physica Medica - October 25, 2008 Category: Physics Authors: Macdonald B, Kirby RL, Smith C, Macleod DA, Webber A Tags: Am J Phys Med Rehabil Source Type: journals

Improper Use of a Transtibial Prosthesis Silicone Liner Causing Pressure Ulceration.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 repeatedl...
Source: Physica Medica - October 25, 2008 Category: Physics Authors: Bruno TR, Kirby RL Tags: Am J Phys Med Rehabil Source Type: journals

Preservation of the Integrity of the Corticospinal Tract in a Patient with Medulla Infarct.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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)
Source: Physica Medica - October 25, 2008 Category: Physics Authors: Jang SH, Yang DS, Lee J Tags: Am J Phys Med Rehabil Source Type: journals

Convex reformulation of biologically-based multi-criteria intensity-modulated radiation therapy optimization including fractionation effects.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 propos...
Source: Physica Medica - October 21, 2008 Category: Physics Authors: Hoffmann AL, den Hertog D, Siem AY, Kaanders JH, Huizenga H Tags: Phys Med Biol Source Type: journals

Real-time determination of the optimal reconstruction phase to control ECG pulsing in spiral cardiac CT.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
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 curv...
Source: Physica Medica - September 30, 2008 Category: Physics Authors: Ertel D, Pflederer T, Achenbach S, Kalender WA Tags: Phys Med Source Type: journals

A statement of the rights of scientists and engineers.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 18760736 [PubMed - in process] (Source: Physica Medica)
Source: Physica Medica - September 1, 2008 Category: Physics Authors: Nüsslin F, Hendee W Tags: Phys Med Source Type: journals