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 'Journal of Medical Physics' source. Thu, 09 Feb 2012 20:29:23 +0100 http://www.medworm.com/index.php?rid=5674161&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2012%2F37%2F1%2F61%2F92722 Journal of Medical Physics 2012 37(1):61-61 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5674161 Wed, 08 Feb 2012 05:00:00 +0100 5674161 http://www.medworm.com/index.php?rid=5674160&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2012%2F37%2F1%2F54%2F92721 Shaban Harb, Abd El-Hadi El-Kamel, Abd El-Bast Abbady, Imran Issa Saleh, Abdallah Ibrahim Abd El-MageedJournal of Medical Physics 2012 37(1):54-60The level of natural radioactivity in rocks and soil of 32 samples collected from locations at North Sana'a in Yemen was measured. Concentrations of radionuclides in rocks and soils samples were determined by gamma-ray spectrometer using high purity germanium (HPGe) detector with specially designed shield. The average radioactivity concentrations of 226 Ra, 232 Th, 40 K were determined and expressed in Bq/kg. The results showed that these radionuclides were present in concentrations of 21.79 ± 3.1, 19.5 ± 2.6 and 399.3 ± 16 Bq/kg, respectively, for rocks. For soil, the corresponding values were 48.2 &#x0... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5674160 Wed, 08 Feb 2012 05:00:00 +0100 5674160 http://www.medworm.com/index.php?rid=5674159&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2012%2F37%2F1%2F46%2F92720 Subhash Chand Kheruka, Brian F Hutton, Umesh Chand Naithani, Lalit Mohan Aggarwal, Nirmal Kumar Painuly, Anil Kumar Maurya, Sanjay GambhirJournal of Medical Physics 2012 37(1):46-53Reconstruction of the tomographic images without attenuation correction can cause erroneously high count densities and reduced image contrast in low attenuation regions. In order to solve the problem of photon attenuation, one needs to know the attenuation coefficient for the individual patient being studied. Therefore, we made an attempt to correct the attenuation map in simultaneous transmission/emission tomography with 153 Gd/ 67 Ga using maximum likelihood method using the expectation maximization (ML-EM) algorithm to correct the transmission window for both the spillover and downscatter. Spillover fraction,... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5674159 Wed, 08 Feb 2012 05:00:00 +0100 5674159 http://www.medworm.com/index.php?rid=5674158&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2012%2F37%2F1%2F40%2F92719 Reena Sharma, Sunil Dutt Sharma, YS MayyaJournal of Medical Physics 2012 37(1):40-45Kodak MinR-2000 mammography film is widely used for mammography imaging. The sensitometric indices like base plus fog level (B + F), maximum optical density (OD max ), average gradient (AG) and speed of this film at varying development temperatures and times were evaluated using a light sensitometer. Totally 33 film strips were cut from a single Kodak MinR-2000 mammography film box and exposed in a light sensitometer operated in the green light spectrum to produce a 21-step sensitometric strip. These exposed film strips were processed at temperatures in the range of 32°C-37°C in the step of 1°C and at processing times in the range of 1-6 minutes in the step of 1 mi... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5674158 Wed, 08 Feb 2012 05:00:00 +0100 5674158 http://www.medworm.com/index.php?rid=5674157&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2012%2F37%2F1%2F32%2F92718 Mahmoud Allahverdi, Alireza Mohammadkarim, Mahbod Esfehani, Hasanali Nedaie, Alireza Shirazi, Ghazale GerailyJournal of Medical Physics 2012 37(1):32-39An in vivo dosimetry system, using p-type diode dosimeters, was characterized for clinical applications of treatment machines ranging in megavoltage energies. This paper investigates two different models of diodes for externally wedged beams and explains a new algorithm for the calculation of the target dose at various tissue depths in external radiotherapy. The values of off-axis wedge correction factors were determined at two different positions in the wedged (toward the thick and thin edges) and in the non-wedged directions on entrance and exit surfaces of a polystyrene phantom in 60 Co and 6 MV photon beams. Depth transmission was defin... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5674157 Wed, 08 Feb 2012 05:00:00 +0100 5674157 http://www.medworm.com/index.php?rid=5674156&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2012%2F37%2F1%2F27%2F92717 Barlanka Ravikumar, S LakshminarayanaJournal of Medical Physics 2012 37(1):27-31In Brachytherapy treatment planning, the effects of tissue heterogeneities are commonly neglected due to lack of accurate, general and fast three-dimensional (3D) dose-computational algorithms. In performing dose calculations, it is assumed that the tumor and surrounding tissues constitute a uniform, homogeneous medium equivalent to water. In the recent past, three-dimensional computed tomography (3D-CT) based treatment planning for Brachytherapy applications has been popularly adopted. However, most of the current commercially available planning systems do not provide the heterogeneity corrections for Brachytherapy dosimetry. In the present study, we have measured and quantified the impact of inhomogeneity cau... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5674156 Wed, 08 Feb 2012 05:00:00 +0100 5674156 http://www.medworm.com/index.php?rid=5674155&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2012%2F37%2F1%2F14%2F92716 Mohammad Mohammadi, Eva BezakJournal of Medical Physics 2012 37(1):14-26The dose delivery verification for a head and neck static intensity modulated radiation therapy (IMRT) case using a scanning liquid ionization chamber electronic portal imaging device (SLIC-EPID) was investigated. Acquired electronic portal images were firstly converted into transmitted dose maps using an in-house developed method. The dose distributions were then compared with those calculated in a virtual EPID using the Pinnacle3 treatment planning system (TPS). Using gamma evaluation with the DDmax and DTA criteria of 3%/2.54 mm, an excellent agreement was observed between transmitted dose measured using SLIC-EPID and that calculated by TPS (gamma score approximately 95%) for large MLC fields. In contr... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5674155 Wed, 08 Feb 2012 05:00:00 +0100 5674155 http://www.medworm.com/index.php?rid=5674154&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2012%2F37%2F1%2F8%2F92715 Marimuthu Sankaralingam, Martin Glegg, Suzanne Smith, Allan James, Mohammed RizwanullahJournal of Medical Physics 2012 37(1):8-13The aim of this study was to compare various dosimetric parameters of dynamic mlc intensity modulated radiotherapy (IMRT) plans with volumetric modulated arc therapy (VMAT) plans for sino-nasal cancers, which are rare and complex tumors to treat with radiotherapy. IMRT using five fields, coplanar in the sagittal plane and VMAT employing two coplanar arc plans were created for five patients. The plans were assessed by comparing Conformity Index and Sigma Index (dose homogeneity) in the Planning Target Volume (PTV) and through comparison of dose-volume characteristics to the following organs at risk (OARs): Spinal cord, brainstem, eye, ipsilateral and contralateral... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5674154 Wed, 08 Feb 2012 05:00:00 +0100 5674154 http://www.medworm.com/index.php?rid=5674153&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2012%2F37%2F1%2F4%2F92714 H Sudahar, P. G. G. Kurup, V Murali, J VelmuruganJournal of Medical Physics 2012 37(1):4-7Dose linearity studies on conventional linear accelerators show a linearity error at low monitor units (MUs). The purpose of this study was to establish the dose linearity and MU stability characteristics of a cyberknife (Accuray Inc., USA) stereotactic radiosurgery system. Measurements were done at a depth of 5 cm in a stereotactic dose verification phantom with a source to surface distance of 75 cm in a Generation 4 (G4) type cyberknife system. All the 12 fixed-type collimators starting from 5 to 60 mm were used for the dose linearity study. The dose linearity was examined in small (1-10), medium (15-100) and large (125-1000) MU ranges. The MU stability test was performed with 60 mm collimator for 1... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5674153 Wed, 08 Feb 2012 05:00:00 +0100 5674153 http://www.medworm.com/index.php?rid=5674152&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2012%2F37%2F1%2F1%2F92713 DD DeshpandeJournal of Medical Physics 2012 37(1):1-3 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5674152 Wed, 08 Feb 2012 05:00:00 +0100 5674152 http://www.medworm.com/index.php?rid=5428442&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F4%2F239%2F89975 Dilip GudeJournal of Medical Physics 2011 36(4):239-240 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5428442 Fri, 18 Nov 2011 05:00:00 +0100 5428442 http://www.medworm.com/index.php?rid=5428441&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F4%2F234%2F89974 Tania De La Fuente Herman, Kerry Hibbitts, Terence Herman, Salahuddin AhmadJournal of Medical Physics 2011 36(4):234-238The aim of this study was to evaluate differences in dose distributions in stereotactic body radiation therapy treatment plans for lung tumors calculated with pencil beam convolution (PBC) algorithm with modified Batho power law (MBPL) versus heterogeneity corrected anisotropic analytical algorithm (AAA) of the Varian Eclipse treatment planning system. The four-dimensional computed tomography images from 20 patients with lung cancer were used to create treatment plans. Plans used five to seven nonopposing coplanar 6 MV beams. Plans generated with the PBC algorithm and MBPL for tissue heterogeneity corrections were optimized to deliver 60 Gy in three fractions to at least ... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5428441 Fri, 18 Nov 2011 05:00:00 +0100 5428441 http://www.medworm.com/index.php?rid=5428440&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F4%2F230%2F89972 Mohammad BakhtiariJournal of Medical Physics 2011 36(4):230-233The effect of surface waves, generated by moving the scanning arms in water phantoms, on radiation dosimetry is studied. It is shown that in large water tanks, high arm speeds can result in dosimetric errors of up to 5%. The measurements that are started after damping the water waves can result in about a 50% improvement in accuracy of measurements. It is shown that the water surfaces at the start of the measurements have high fluctuations that transform to a steady phase by elapsing time. (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5428440 Fri, 18 Nov 2011 05:00:00 +0100 5428440 http://www.medworm.com/index.php?rid=5428439&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F4%2F220%2F89971 Arun S Oinam, Lakhwant Singh, Arvind Shukla, Sushmita Ghoshal, Rakesh Kapoor, Suresh C SharmaJournal of Medical Physics 2011 36(4):220-229The purpose of this study is to compare Lyman-Kutcher-Burman (LKB) model versus Niemierko model for normal tissue complication probability (NTCP) calculation and Niemierko model versus Poisson-based model for tumor control probability (TCP) calculation in the ranking of different treatment plans for a patient undergoing radiotherapy. The standard normal tissue tolerance data were used to test the NTCP models. LKB model can reproduce the same complication probability data of normal tissue response on radiation, whereas Niemierko model cannot reproduce the same complication probability. Both Poisson-based and Niemierko models equally reproduce the same sta... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5428439 Fri, 18 Nov 2011 05:00:00 +0100 5428439 http://www.medworm.com/index.php?rid=5428438&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F4%2F213%2F89970 We present these changes in the form of predictive formulas, which would be useful in clinical applications. (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5428438 Fri, 18 Nov 2011 05:00:00 +0100 5428438 http://www.medworm.com/index.php?rid=5428437&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F4%2F205%2F89969 Hassan S Abou-elenein, Ehab M Attalla, H Ammar, Ismail Eldesoky, Mohamed Farouk, Mohamed S ZaghloulJournal of Medical Physics 2011 36(4):205-212The improvement in conformal radiotherapy techniques enables us to achieve steep dose gradients around the target which allows the delivery of higher doses to a tumor volume while maintaining the sparing of surrounding normal tissue. One of the reasons for this improvement was the implementation of intensity-modulated radio therapy (IMRT) by using linear accelerators fitted with multi-leaf collimator (MLC), Tomo therapy and Rapid arc. In this situation, verification of patient set-up and evaluation of internal organ motion just prior to radiation delivery become important. To this end, several volumetric image-guided techniques have been developed ... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5428437 Fri, 18 Nov 2011 05:00:00 +0100 5428437 http://www.medworm.com/index.php?rid=5428436&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F4%2F198%2F89967 This study suggests that the effective path length based algorithm of the ASHA radiotherapy TPS is unable to achieve the recommended 3% accuracy of clinical dose calculation in heterogeneous media. (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5428436 Fri, 18 Nov 2011 05:00:00 +0100 5428436 http://www.medworm.com/index.php?rid=5428435&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F4%2F192%2F89965 In this study, a simple index, Plan Normal tissue complication Index (PNI) has been proposed for treatment plan evaluation based on the dose to surrounding critical structures. To demonstrate the proposed index, four different critical treatment sites that include the prostate, upper abdominal cancer, lung, and head and neck were selected for this study. A software progam (PNIcalc) has been developed to compute the PNI from the exported dose-volume histogram data and from the tissue tolerance data published by Emami et al. and Kehwar et al. The software also shows the parameters that exceed the threshold limits of dose-volume parameters presented in the QUANTEC recommendations (2010). In all the studied cases, PNI gave an overall picture of the dose received by the critical structures and ... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5428435 Fri, 18 Nov 2011 05:00:00 +0100 5428435 http://www.medworm.com/index.php?rid=5428434&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F4%2F189%2F89963 L John SchreinerJournal of Medical Physics 2011 36(4):189-191 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5428434 Fri, 18 Nov 2011 05:00:00 +0100 5428434 http://www.medworm.com/index.php?rid=5094417&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F3%2F186%2F83503 T GaneshJournal of Medical Physics 2011 36(3):186-188 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5094417 Wed, 03 Aug 2011 23:00:00 +0100 5094417 http://www.medworm.com/index.php?rid=5094416&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F3%2F184%2F83502 R RavichandranJournal of Medical Physics 2011 36(3):184-185 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5094416 Wed, 03 Aug 2011 23:00:00 +0100 5094416 http://www.medworm.com/index.php?rid=5094415&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F3%2F181%2F83501 Ramamoorthy Ravichandran, Saju Bhasi, JP Binukumar, CA DavisJournal of Medical Physics 2011 36(3):181-183 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5094415 Wed, 03 Aug 2011 23:00:00 +0100 5094415 http://www.medworm.com/index.php?rid=5094414&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F3%2F176%2F83497 This article describes different tests done after commissioning to evaluate the level of agreement between matched beams of two ONCOR Impression plus linear accelerators from Siemens. Total scatter factors, collimator scatter factors, wedge transmission factors were measured in water for 6-MV photon. All these factors for ONCOR2 were within ±1% of those values for ONCOR1. Along with these point dose measurements we have essentially used γ-index to compare the planar dose distribution from two beam-matched accelerators. For this study a set of ready packed EDR2 films was exposed on both accelerators. The set consisted of films for percentage depth dose, beam profiles, a pyramid shape, multileaf collimator's positional and dose delivery accuracy, and a f... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5094414 Wed, 03 Aug 2011 23:00:00 +0100 5094414 http://www.medworm.com/index.php?rid=5094413&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F3%2F171%2F83491 This study demonstrates dosimetric quality assurance of the HDR brachytherapy using a commercially available two-dimensional ion chamber array called IMatriXX, which has a detector separation of 0.7619 cm. The reference isodose length, step size, and source dwell positional accuracy were verified. A total of 24 dwell positions, which were verified for positional accuracy gave a total error (systematic and random) of −0.45 mm, with a standard deviation of 1.01 mm and maximum error of 1.8 mm. Using a step size of 5 mm, reference isodose length (the length of 100% isodose line) was verified for single and multiple catheters of same and different source loadings. An error ≤1 mm was measured in 57% of tests analyzed. Step size verification for 2, 3, 4, an... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5094413 Wed, 03 Aug 2011 23:00:00 +0100 5094413 http://www.medworm.com/index.php?rid=5094412&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F3%2F159%2F83482 Amir H Golnabi, Paul M Meaney, Shireen D Geimer, Keith D PaulsenJournal of Medical Physics 2011 36(3):159-170Microwave imaging for medical applications is attractive because the range of dielectric properties of different soft tissues can be substantial. Breast cancer detection and monitoring of treatment response are areas where this technology could be important because of the contrast between normal and malignant tissue. Unfortunately, the technique is unable to achieve the high spatial resolution at depth in tissue which is available from other conventional modalities such as x-ray computed tomography (CT) or magnetic resonance imaging (MRI). We have incorporated a soft-prior regularization strategy within our microwave reconstruction algorithm and compared it with the images obtained ... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5094412 Wed, 03 Aug 2011 23:00:00 +0100 5094412 http://www.medworm.com/index.php?rid=5094411&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F3%2F147%2F83481 C Vijayakumar, Damayanti Chandrashekhar GharpureJournal of Medical Physics 2011 36(3):147-158Most of the commercially available software for brain tumor segmentation have limited functionality and frequently lack the careful validation that is required for clinical studies. We have developed an image-analysis software package called 'Prometheus,' which performs neural system-based segmentation operations on MR images using pre-trained information. The software also has the capability to improve its segmentation performance by using the training module of the neural system. The aim of this article is to present the design and modules of this software. The segmentation module of Prometheus can be used primarily for image analysis in MR images. Prometheus was validated against m... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5094411 Wed, 03 Aug 2011 23:00:00 +0100 5094411 http://www.medworm.com/index.php?rid=5094410&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F3%2F138%2F83478 Wilbroad Muhogora, Renato Padovani, Faustino Bonutti, Peter Msaki, R KazemaJournal of Medical Physics 2011 36(3):138-146The performances of three clinical computed radiography (CR) systems, (Agfa CR 75 (with CRMD 4.0 image plates), Kodak CR 850 (with Kodak GP plates) and Kodak CR 850A (with Kodak GP plates)) were evaluated using six tests recommended in American Association of Physicists in Medicine Report 93. The results indicated variable performances with majority being within acceptable limits. The variations were mainly attributed to differences in detector formulations, plate readers' characteristics, and aging effects. The differences of the mean low contrast scores between the imaging systems for three observers were statistically significant for Agfa and Kodak CR 850A (P=0.... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5094410 Wed, 03 Aug 2011 23:00:00 +0100 5094410 http://www.medworm.com/index.php?rid=5094409&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F3%2F133%2F83475 C Varatharaj, M Ravikumar, S Sathiyan, Sanjay S SupeJournal of Medical Physics 2011 36(3):133-137The use of megavoltage X-ray sources of radiation, with their skin-sparing qualities in radiation therapy, has been proved useful in relieving patient discomfort and allowing higher tumor doses to be given with fewer restrictions due to radiation effects in the skin. The purpose of this study was to compare the dosimetric characteristics of a physical and enhanced dynamic wedge from a dual-energy (6 and 18 MV) linear accelerator such as surfaces doses with different source to surface distances (SSD), half value layer (HVL) in water and peripheral doses for both available energies. At short SSD such as 85 cm, higher surface doses are produced by the lower wedges by the short wedge-to-skin distan... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5094409 Wed, 03 Aug 2011 23:00:00 +0100 5094409 http://www.medworm.com/index.php?rid=5094408&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F3%2F126%2F83466 Francisco Cutanda Henríquez, Silvia Vargas CastrillónJournal of Medical Physics 2011 36(3):126-132Equivalent uniform dose (EUD) is the absorbed dose that, when homogeneously given to a tumor, yields the same mean surviving clonogen number as the given non-homogeneous irradiation. EUD is used as an evaluation tool under the assumption that two plans with the same value of EUD are equivalent, and their biological effect on the tumor (clonogen survival) would be the same as the one of a homogeneous irradiation of absorbed dose EUD. In this work, this assumption has been studied, and a figure of merit of its applicability has been obtained. Distributions of surviving clonogen number for homogeneous and non-homogeneous irradiations are found to be different even if their mean valu... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5094408 Wed, 03 Aug 2011 23:00:00 +0100 5094408 http://www.medworm.com/index.php?rid=5094407&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F3%2F123%2F83464 Sunil Dutt SharmaJournal of Medical Physics 2011 36(3):123-125 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=5094407 Wed, 03 Aug 2011 23:00:00 +0100 5094407 http://www.medworm.com/index.php?rid=4723105&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F2%2F117%2F79685 T GaneshJournal of Medical Physics 2011 36(2):117-121 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4723105 Sun, 17 Apr 2011 23:00:00 +0100 4723105 http://www.medworm.com/index.php?rid=4723104&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F2%2F111%2F79687 B Shwetha, M Ravikumar, Siddanna R Palled, Sanjay S Supe, S SathiyanJournal of Medical Physics 2011 36(2):111-116Intracavitary brachytherapy is an integral part of radiotherapy for locally advanced gynecologic malignancies. A dosimetric intercomparison of high dose rate intracavitary brachytherapy (HDR_BT) and intensity-modulated radiotherapy in cervical carcinoma has been made in the present study. CT scan images of 10 patients treated with HDR_BT were used for this study. A sliding-window IMRT (IMRT_SW) and step-and-shoot IMRT plans were generated using 6-MV X-rays. The cumulative dose volume histograms of target, bladder, rectum and normal tissue were analyzed for both techniques and dose distributions were compared. It was seen that the pear-shaped dose distribution characteristic of i... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4723104 Sun, 17 Apr 2011 23:00:00 +0100 4723104 http://www.medworm.com/index.php?rid=4723103&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F2%2F107%2F79688 BJ Healy, RL MurryJournal of Medical Physics 2011 36(2):107-110Quality assurance of external-beam treatment-planning systems is recommended, and this can be partly achieved with predefined type tests. The beam data and test geometries of IAEA TECDOC 1540 have been used to test the analytical anisotropic algorithm (AAA) and pencil-beam convolution (PBC) algorithm of the Varian Eclipse treatment planning system. Beam models were created in Eclipse for 6 MV, 10 MV and 18 MV from the available beam data. Twelve test geometries were re-created in Eclipse, and the differences between Eclipse dose calculations and dose measurements were recorded. The AAA algorithm generally performed better than the PBC algorithm for the 12 tests, but both algorithms did not meet predefined tolerances for asymmet... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4723103 Sun, 17 Apr 2011 23:00:00 +0100 4723103 http://www.medworm.com/index.php?rid=4723102&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F2%2F100%2F79689 Frederick W McKenna, Salahuddin AhmadJournal of Medical Physics 2011 36(2):100-106The linear quadratic is the standard model for calculating isoeffects in the range of conventional dose per fraction. However, the use of hypofractionation and stereotactic body radiation therapy can call for isoeffect calculations for large doses per fraction. The purpose of this work is to investigate the linear quadratic at large doses per fraction. The linear quadratic is compared to models that incorporate effects such as dose protraction, whose purpose is to extend the useful range of the linear quadratic to larger doses. The linear quadratic and extended linear quadratic models are fit to 4 data sets. The model-predicted isoeffects for these data sets are calculated. It is found that the linear quadrat... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4723102 Sun, 17 Apr 2011 23:00:00 +0100 4723102 http://www.medworm.com/index.php?rid=4723101&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F2%2F95%2F79692 R Ravichandran, JP Binukumar, Rajan Sreeram, LS ArunkumarJournal of Medical Physics 2011 36(2):95-99Radioactive wastes from hospitals form one of the various types of urban wastes, which are managed in developed countries in a safe and organized way. In countries where growth of nuclear medicine services are envisaged, implementations of existing regulatory policies and guidelines in hospitals in terms of handling of radioactive materials used in the treatment of patients need a good model. To address this issue, a brief description of the methods is presented. A designed prototype waste storage trolley is found to be of great help in decaying the I-131 solid wastes from wards before releasing to waste treatment plant of the city. Two delay tanks with collection time of about 2 months and ... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4723101 Sun, 17 Apr 2011 23:00:00 +0100 4723101 http://www.medworm.com/index.php?rid=4723100&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F2%2F85%2F79693 Ranganathan Vaitheeswaran, VK Sathiya Narayanan, Janhavi R Bhangle, Amit Nirhali, Namita Kumar, Sumit Basu, Vikram MaiyaJournal of Medical Physics 2011 36(2):85-94The study aims to introduce a hybrid optimization algorithm for anatomy-based intensity modulated radiotherapy (AB-IMRT). Our proposal is that by integrating an exact optimization algorithm with a heuristic optimization algorithm, the advantages of both the algorithms can be combined, which will lead to an efficient global optimizer solving the problem at a very fast rate. Our hybrid approach combines Gaussian elimination algorithm (exact optimizer) with fast simulated annealing algorithm (a heuristic global optimizer) for the optimization of beam weights in AB-IMRT. The algorithm has been implemented using MATLAB software. The o... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4723100 Sun, 17 Apr 2011 23:00:00 +0100 4723100 http://www.medworm.com/index.php?rid=4723099&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F2%2F78%2F79691 Seonkyu Kim, Myonggeun Yoon, Dong Ho Shin, Dongwook Kim, Sangyeob Lee, Se Byeong Lee, Sung Yong Park, Sang Hyuk SongJournal of Medical Physics 2011 36(2):78-84To evaluate the feasibility of tumor-tracking radiotherapy that does not consider tumor deformation during respiration. Four-dimensional computed tomography (4D-CT) data, which considers 10 phases of the respiration cycle, were acquired in 4 patients with lung cancer and 4 patients with liver cancer. Initial treatment plans were established at the end of the inhalation phase (phase 1). As a simulation of deformation-free tumor-tracking radiotherapy, the beam center of the initial plan was moved to the tumor center for all other phases, and the tumor shape acquired from phase 1 was used for all 10 phases. The feasibility of this metho... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4723099 Sun, 17 Apr 2011 23:00:00 +0100 4723099 http://www.medworm.com/index.php?rid=4723098&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F2%2F72%2F79690 SA Yoganathan, Karthick Raj Mani, KJ Maria Das, Arpita Agarwal, Shaleen KumarJournal of Medical Physics 2011 36(2):72-77The purpose of this study was to evaluate the dosimetric effect of the leaf width of a multileaf collimator (MLC) in intensity-modulated radiotherapy (IMRT) delivery techniques for small- and large-volume targets. We retrospectively selected previously treated 5 intracranial and 5 head-neck patients for this study to represent small- (range, 18.37-72.75 cc; mean, 42.99 cc) and large-volume (range, 312.31-472.84 cc; mean, 361.14 cc) targets. A 6-MV photon beam data was configured for Brianlab m3 (3 mm), Varian Millennium 120 (5 mm) and Millennium 80 (10 mm) MLCs in the Eclipse treatment-planning system. Sliding window and step-shoot IMRT plans were generated for intracrani... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4723098 Sun, 17 Apr 2011 23:00:00 +0100 4723098 http://www.medworm.com/index.php?rid=4723097&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F2%2F59%2F79686 Michael L Taylor, Tomas KronJournal of Medical Physics 2011 36(2):59-71Radiation delivery to cancer patients for radiotherapy is invariably accompanied by unwanted radiation to other parts of the patient's body. Traditionally, considerable effort has been made to calculate and measure the radiation dose to the target as well as to nearby critical structures. Only recently has attention been focused also on the relatively low doses that exist far from the primary radiation beams. In several clinical scenarios, such doses have been associated with cardiac toxicity as well as an increased risk of secondary cancer induction. Out-of-field dose is a result of leakage and scatter and generally difficult to predict accurately. The present review aims to present existing data, from measureme... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4723097 Sun, 17 Apr 2011 23:00:00 +0100 4723097 http://www.medworm.com/index.php?rid=4723096&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F2%2F57%2F79684 AK ShuklaJournal of Medical Physics 2011 36(2):57-58 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4723096 Sun, 17 Apr 2011 23:00:00 +0100 4723096 http://www.medworm.com/index.php?rid=4337174&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F1%2F53%2F75474 Journal of Medical Physics 2011 36(1):53-53 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4337174 Wed, 12 Jan 2011 00:00:00 +0100 4337174 http://www.medworm.com/index.php?rid=4337173&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F1%2F51%2F75473 T GaneshJournal of Medical Physics 2011 36(1):51-52 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4337173 Wed, 12 Jan 2011 00:00:00 +0100 4337173 http://www.medworm.com/index.php?rid=4337172&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F1%2F46%2F75472 Ramamoorthy Ravichandran, JP BinukumarJournal of Medical Physics 2011 36(1):46-50International Basic Safety Standards (International Atomic Energy Agency, IAEA) provide guidance levels for diagnostic procedures in nuclear medicine indicating the maximum usual activity for various diagnostic tests in terms of activities of injected radioactive formulations. An accuracy of ± 10% in the activities of administered radio-pharmaceuticals is being recommended, for expected outcome in diagnostic and therapeutic nuclear medicine procedures. It is recommended that the long-term stability of isotope calibrators used in nuclear medicine is to be checked periodically for their performance using a long-lived check source, such as Cs-137, of suitable activity. In view of the un-availab... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4337172 Wed, 12 Jan 2011 00:00:00 +0100 4337172 http://www.medworm.com/index.php?rid=4337171&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F1%2F40%2F75471 This study intends to evaluate radiation doses imparted to patients undergoing thorax, abdomen and pelvic CT examinations and formulate regional diagnostic reference levels (DRL) in Tamil Nadu, South India. In-site CT dose measurement was performed in 127 CT scanners in Tamil Nadu for a period of 2 years as a part of the Atomic Energy Regulatory Board (AERB)-funded project. Out of the 127 CT scanners,13 were conventional; 53 single-slice helical scanners (SSHS); 44 multislice CT (MSCT) scanners; and 17 refurbished scanners. CT dose index (CTDI) was measured using a 32-cm polymethyl methacrylate (PMMA)-body phantom in each CT scanner. Dose length product (DLP) for different anatomical regions was generated using CTDI values. The regional DRLs for thorax, abdomen and pelvis examinations were... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4337171 Wed, 12 Jan 2011 00:00:00 +0100 4337171 http://www.medworm.com/index.php?rid=4337170&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F1%2F35%2F75470 In this study, four dimensional computed tomography (4DCT) scanning was performed during free breathing on a 16-slice Positron emission tomography PET /computed tomography (CT) for abdomen and thoracic patients. Images were sorted into 10 phases based on the temporal correlation between surface motion and data acquisition with an Advantage Workstation. Gross tumor volume gross tumor volume (GTV) s were manually contoured on all 10 phases of the 4DCT scan. GTVs in the multiple CT phases were called GTV4D. GTV4D plus an isotropic margin of 1.0 cm was called CTV4D. Two sets of planning target volume (PTV) 4D (PTV4D) were derived from the CTV4D, i.e. PTV4D 2cm = CTV4D plus 1 cm setup margin (SM) and 1 cm internal margin (IM) and PTV4D 1.5cm = CTV4D plus 1 cm SM and 0.5cm IM. PTV3D was derived ... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4337170 Wed, 12 Jan 2011 00:00:00 +0100 4337170 http://www.medworm.com/index.php?rid=4337169&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F1%2F29%2F75469 Sundaram Thangavelu, S Jayakumar, KN Govindarajan, Sanjay S Supe, V Nagarajan, M NagarajanJournal of Medical Physics 2011 36(1):29-34The goal of the present study was to study the effects of low- and high-energy intensity-modulated photon beams on the planning of target volume and the critical organs in cases of localized prostate tumors in a cohort of 8 patients. To ensure that the difference between the plans is due to energy alone, all other parameters were kept constant. A mean dose volume histogram (DVH) for each value of energy and for each contoured structure was created and was considered as completely representative for all patients. To facilitate comparison between 6-MV and 15-MV beams, the DVH-s were normalized. The different parameters that were compared for 6-MV and 15-MV beam... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4337169 Wed, 12 Jan 2011 00:00:00 +0100 4337169 http://www.medworm.com/index.php?rid=4337168&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F1%2F22%2F75468 Wilbroad Muhogora, Renato Padovani, Peter MsakiJournal of Medical Physics 2011 36(1):22-28The aim of this study was to develop a homemade phantom for quantitative quality control in chest computed radiography (CR). The phantom was constructed from copper, aluminium, and polymenthylmethacrylate (PMMA) plates as well as Styrofoam materials. Depending on combinations, the literature suggests that these materials can simulate the attenuation and scattering characteristics of lung, heart, and mediastinum. The lung, heart, and mediastinum regions were simulated by 10 mm x 10 mm x 0.5 mm, 10 mm x 10 mm x 0.5 mm and 10 mm x 10 mm x 1 mm copper plates, respectively. A test object of 100 mm x 100 mm and 0.2 mm thick copper was positioned to each region for CNR measurements. The phantom was exposed t... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4337168 Wed, 12 Jan 2011 00:00:00 +0100 4337168 http://www.medworm.com/index.php?rid=4337167&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F1%2F15%2F75467 This study ensures that the dosimetric calculations performed by the TPS are within the accuracy of ±5% which is very much warranted in patient dose delivery. The test procedures are simple, not only during the installation of TPS, but also repeated at periodic intervals. (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4337167 Wed, 12 Jan 2011 00:00:00 +0100 4337167 http://www.medworm.com/index.php?rid=4337166&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F1%2F3%2F75466 Timothy Olding, Oliver Holmes, Paul DeJean, Kim B McAuley, Ken Nkongchu, Giles Santyr, L John SchreinerJournal of Medical Physics 2011 36(1):3-14This paper explores the combination of cone beam optical computed tomography with an N-isopropylacrylamide (NIPAM)-based polymer gel dosimeter for three-dimensional dose imaging of small field deliveries. Initial investigations indicate that cone beam optical imaging of polymer gels is complicated by scattered stray light perturbation. This can lead to significant dosimetry failures in comparison to dose readout by magnetic resonance imaging (MRI). For example, only 60% of the voxels from an optical CT dose readout of a 1 l dosimeter passed a two-dimensional Low's gamma test (at a 3%, 3 mm criteria, relative to a treatment pla... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4337166 Wed, 12 Jan 2011 00:00:00 +0100 4337166 http://www.medworm.com/index.php?rid=4337165&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2011%2F36%2F1%2F1%2F75465 AS PradhanJournal of Medical Physics 2011 36(1):1-2 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4337165 Wed, 12 Jan 2011 00:00:00 +0100 4337165 http://www.medworm.com/index.php?rid=4081425&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D4%3Bspage%3D247%3Bepage%3D248%3Baulast%3D Journal of Medical Physics 2010 35(4):247-248 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4081425 Tue, 19 Oct 2010 20:08:22 +0100 4081425 http://www.medworm.com/index.php?rid=4081424&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D4%3Bspage%3D242%3Bepage%3D246%3Baulast%3DObed RI Obed, HT Lateef, AK AdemolaJournal of Medical Physics 2010 35(4):242-246CR-39 tracketch detectors were used for the measurement of 222 Rn concentration in 24 offices in Nigeria's oldest university campus in order to estimate the effective dose to the occupants from 222 Rn and its progeny. The dosimetric measurements were made over a period of 3 months. Questionnaires were distributed and analyzed. The radon concentration ranged from 157 to 495 Bq /m 3 , with an arithmetic mean and standard deviation of 293.3 and 79.6 Bq/ m 3 , respectively. The effective dose to the workers was estimated and this varied from 0.99 to 3.12 mSv/ y, with a mean of 1.85 mSv /y. The radon concentrations were found to be within the reference levels of ICRP. (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4081424 Tue, 19 Oct 2010 20:08:22 +0100 4081424 http://www.medworm.com/index.php?rid=4081423&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D4%3Bspage%3D235%3Bepage%3D241%3Baulast%3DMaharana Mandakini Maharana, Narayani Krishnan, D SenguptaJournal of Medical Physics 2010 35(4):235-241The concentrations of natural radionuclides in surface soil samples around selected villages of Jaduguda were investigated and compared with the radioactivity level in the region. Concentrations of 238 U, 232 Th, and 40 K were determined by a gamma ray spectrometer using the HPGe detector with 50% relative efficiency, and the radiation dose to the local population was estimated. The average estimated activity concentrations of 238 U, 232 Th, and 40 K in the surface soil were 53.8, 44.2 and 464.2 Bq kg -1 respectively. The average absorbed dose rate in the study area was estimated to be 72.5 nGy h-1, where as the annual effective dose to the population was 0.09 mSv y-1. A correlation analysi... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4081423 Tue, 19 Oct 2010 20:08:22 +0100 4081423 http://www.medworm.com/index.php?rid=4081422&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D4%3Bspage%3D229%3Bepage%3D234%3Baulast%3DSonawane AU Sonawane, Meghraj Singh, J. V. K. Sunil Kumar, Arti Kulkarni, VK Shirva, AS PradhanJournal of Medical Physics 2010 35(4):229-234We conducted a radiological safety and quality assurance (QA) audit of 118 medical X-ray diagnostic machines installed in 45 major hospitals in India. The main objective of the audit was to verify compliance with the regulatory requirements stipulated by the national regulatory body. The audit mainly covered accuracy check of accelerating potential (kVp), linearity of tube current (mA station) and timer, congruence of radiation and optical field, and total filtration; in addition, we also reviewed medical X-ray diagnostic installations with reference to room layout of X-ray machines and conduct of radiological protection survey. A QA kit consisting of a kVp Tes... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4081422 Tue, 19 Oct 2010 20:08:22 +0100 4081422 http://www.medworm.com/index.php?rid=4081421&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D4%3Bspage%3D223%3Bepage%3D228%3Baulast%3DHedlund Elisabeth Hedlund, Jan-Erik Karlsson, Sven-Åke StarckJournal of Medical Physics 2010 35(4):223-228In the clinical diagnosis of neuroendocrine tumors (NET), the results of examinations, such as high-resolution computed tomography (CT) and single photon computerized tomography (SPECT), have conventionally been interpreted separately. The aim of the present study was to evaluate Hermes Multimodality™ 5.0 H Image Fusion software-based automatic and manual image fusion of SPECT and CT for the localization of NET lesions. Out of 34 NET patients who were examined by means of somatostatin receptor scintigraphy (SRS) with 111In- pentetreotide along with SPECT, 22 patients had a CT examination of the abdomen, which was used in the fusion analysis. SPECT and CT data were fused usi... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4081421 Tue, 19 Oct 2010 20:08:22 +0100 4081421 http://www.medworm.com/index.php?rid=4081420&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D4%3Bspage%3D215%3Bepage%3D222%3Baulast%3Dde Robin de Nijs, Søren Holm, Gerda Thomsen, Morten Ziebell, Claus SvarerJournal of Medical Physics 2010 35(4):215-222Correction for downscatter in I-123 SPECT can be performed by the subtraction of a secondary energy window from the main window, as in the triple-energy window method. This is potentially noise sensitive. For studies with limited amount of counts (e.g. dynamic studies), a broad subtraction window with identical width is preferred. This secondary window needs to be weighted with a factor higher than one, due to a broad backscatter peak from high-energy photons appearing at 172 keV. Spatial dependency and the numerical value of this weighting factor and the image contrast improvement of this correction were investigated in this study. Energy windows with a width of 32 keV... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4081420 Tue, 19 Oct 2010 20:08:22 +0100 4081420 http://www.medworm.com/index.php?rid=4081419&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D4%3Bspage%3D207%3Bepage%3D214%3Baulast%3DArunkumar T Arunkumar, Sanjay S Supe, M Ravikumar, S Sathiyan, M GaneshJournal of Medical Physics 2010 35(4):207-214Electron beam therapy is widely used in the management of cancers. The rapid dose fall-off and the short range of an electron beam enable the treatment of lesions close to the surface, while sparing the underlying tissues. In an extended source-to-surface (SSD) treatment with irregular field sizes defined by cerrobend cutouts, underdosage of the lateral tissue may occur due to reduced beam flatness and uniformity. To study the changes in the beam characteristics, the depth dose, beam profile, and isodose distributions were measured at different SSDs for regular 10 Χ 10 cm 2 and 15 Χ 15 cm 2 cone, and for irregular cutouts of field size 6.5 Χ 9 cm 2 a... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4081419 Tue, 19 Oct 2010 20:08:22 +0100 4081419 http://www.medworm.com/index.php?rid=4081418&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D4%3Bspage%3D202%3Bepage%3D206%3Baulast%3DYadav Girigesh Yadav, RS Yadav, Alok KumarJournal of Medical Physics 2010 35(4):202-206The purpose of this study was to find out the effect of various physical parameters on the skin and build-up doses of 15-MV photon beams. The effects of field dimensions, acrylic shadow tray, focus to-skin distance (FSD) on surface and buildup dose were determined for open, motorized 60° wedge (MW) and blocked fields. A 'Markus' plane parallel plate chamber was used for these measurements in an Elekta (6-15MV) linear accelerator. The surface dose for MW fields was lower than the dose for an open field, but the trend reversed for large fields and higher degree wedges. With the use of an acrylic shadow tray, the surface dose increased for all field sizes, but the increase was dominant f... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4081418 Tue, 19 Oct 2010 20:08:22 +0100 4081418 http://www.medworm.com/index.php?rid=4081417&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D4%3Bspage%3D197%3Bepage%3D201%3Baulast%3DGossman Michael S Gossman, Morris I BankJournal of Medical Physics 2010 35(4):197-201Dose-volume histograms provide key information to radiation oncologists when they assess the adequacy of a patient treatment plan in radiation therapy. It is important therefore that all clinically relevant data be accurate. In this article we present the first quality assurance routine involving a direct comparison of planning system results with the results obtained from independent hand calculations. Given a known three-dimensional (3-D) structure such as a parallelepiped, a simple beam arrangement, and known physics beam data, a time-efficient and reproducible method for verifying the accuracy of volumetric statistics (DVH) from a radiation therapy treatment planning system (TPS) can be employed rapidly, satis... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4081417 Tue, 19 Oct 2010 20:08:22 +0100 4081417 http://www.medworm.com/index.php?rid=4081416&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D4%3Bspage%3D189%3Bepage%3D196%3Baulast%3DVaratharaj C Varatharaj, Eugenia Moretti, M Ravikumar, Maria Rosa Malisan, Sanjay S Supe, Renato PadovaniJournal of Medical Physics 2010 35(4):189-196Electronic portal imaging devices (EPIDs) are extensively used for obtaining dosimetric information of pre-treatment field verification and in-vivo dosimetry for intensity-modulated radiotherapy (IMRT). In the present study, we have implemented the newly developed portal dosimetry software using independent dose prediction algorithm EPIDose TM and evaluated this new tool for the pre-treatment IMRT plan quality assurance of Whole Pelvis with Simultaneous Integrated Boost (WP-SIB-IMRT ) of prostate cases by comparing with routine two-dimensional (2D) array detector system (MapCHECK TM ). We have investigated 104 split fields using g-distributions in terms... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4081416 Tue, 19 Oct 2010 20:08:22 +0100 4081416 http://www.medworm.com/index.php?rid=4081415&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D4%3Bspage%3D187%3Bepage%3D188%3Baulast%3DPradhan AS PradhanJournal of Medical Physics 2010 35(4):187-188 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4081415 Tue, 19 Oct 2010 20:08:22 +0100 4081415 http://www.medworm.com/index.php?rid=4096319&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2010%2F35%2F4%2F247%2F71757 Journal of Medical Physics 2010 35(4):247-248 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4096319 Mon, 18 Oct 2010 23:00:00 +0100 4096319 http://www.medworm.com/index.php?rid=4096318&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2010%2F35%2F4%2F242%2F71760 RI Obed, HT Lateef, AK AdemolaJournal of Medical Physics 2010 35(4):242-246CR-39 tracketch detectors were used for the measurement of 222 Rn concentration in 24 offices in Nigeria's oldest university campus in order to estimate the effective dose to the occupants from 222 Rn and its progeny. The dosimetric measurements were made over a period of 3 months. Questionnaires were distributed and analyzed. The radon concentration ranged from 157 to 495 Bq /m 3 , with an arithmetic mean and standard deviation of 293.3 and 79.6 Bq/ m 3 , respectively. The effective dose to the workers was estimated and this varied from 0.99 to 3.12 mSv/ y, with a mean of 1.85 mSv /y. The radon concentrations were found to be within the reference levels of ICRP. (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4096318 Mon, 18 Oct 2010 23:00:00 +0100 4096318 http://www.medworm.com/index.php?rid=4096317&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2010%2F35%2F4%2F235%2F71762 Mandakini Maharana, Narayani Krishnan, D SenguptaJournal of Medical Physics 2010 35(4):235-241The concentrations of natural radionuclides in surface soil samples around selected villages of Jaduguda were investigated and compared with the radioactivity level in the region. Concentrations of 238 U, 232 Th, and 40 K were determined by a gamma ray spectrometer using the HPGe detector with 50% relative efficiency, and the radiation dose to the local population was estimated. The average estimated activity concentrations of 238 U, 232 Th, and 40 K in the surface soil were 53.8, 44.2 and 464.2 Bq kg -1 respectively. The average absorbed dose rate in the study area was estimated to be 72.5 nGy h-1, where as the annual effective dose to the population was 0.09 mSv y-1. A correlation analysi... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4096317 Mon, 18 Oct 2010 23:00:00 +0100 4096317 http://www.medworm.com/index.php?rid=4096316&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2010%2F35%2F4%2F229%2F71764 AU Sonawane, Meghraj Singh, J. V. K. Sunil Kumar, Arti Kulkarni, VK Shirva, AS PradhanJournal of Medical Physics 2010 35(4):229-234We conducted a radiological safety and quality assurance (QA) audit of 118 medical X-ray diagnostic machines installed in 45 major hospitals in India. The main objective of the audit was to verify compliance with the regulatory requirements stipulated by the national regulatory body. The audit mainly covered accuracy check of accelerating potential (kVp), linearity of tube current (mA station) and timer, congruence of radiation and optical field, and total filtration; in addition, we also reviewed medical X-ray diagnostic installations with reference to room layout of X-ray machines and conduct of radiological protection survey. A QA kit consisting of a kVp Tes... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4096316 Mon, 18 Oct 2010 23:00:00 +0100 4096316 http://www.medworm.com/index.php?rid=4096315&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2010%2F35%2F4%2F223%2F71766 Elisabeth Hedlund, Jan-Erik Karlsson, Sven-Åke StarckJournal of Medical Physics 2010 35(4):223-228In the clinical diagnosis of neuroendocrine tumors (NET), the results of examinations, such as high-resolution computed tomography (CT) and single photon computerized tomography (SPECT), have conventionally been interpreted separately. The aim of the present study was to evaluate Hermes Multimodality™ 5.0 H Image Fusion software-based automatic and manual image fusion of SPECT and CT for the localization of NET lesions. Out of 34 NET patients who were examined by means of somatostatin receptor scintigraphy (SRS) with 111In- pentetreotide along with SPECT, 22 patients had a CT examination of the abdomen, which was used in the fusion analysis. SPECT and CT data were fused usi... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4096315 Mon, 18 Oct 2010 23:00:00 +0100 4096315 http://www.medworm.com/index.php?rid=4096314&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2010%2F35%2F4%2F215%2F71765 Robin de Nijs, Søren Holm, Gerda Thomsen, Morten Ziebell, Claus SvarerJournal of Medical Physics 2010 35(4):215-222Correction for downscatter in I-123 SPECT can be performed by the subtraction of a secondary energy window from the main window, as in the triple-energy window method. This is potentially noise sensitive. For studies with limited amount of counts (e.g. dynamic studies), a broad subtraction window with identical width is preferred. This secondary window needs to be weighted with a factor higher than one, due to a broad backscatter peak from high-energy photons appearing at 172 keV. Spatial dependency and the numerical value of this weighting factor and the image contrast improvement of this correction were investigated in this study. Energy windows with a width of 32 keV... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4096314 Mon, 18 Oct 2010 23:00:00 +0100 4096314 http://www.medworm.com/index.php?rid=4096313&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2010%2F35%2F4%2F207%2F71763 T Arunkumar, Sanjay S Supe, M Ravikumar, S Sathiyan, M GaneshJournal of Medical Physics 2010 35(4):207-214Electron beam therapy is widely used in the management of cancers. The rapid dose fall-off and the short range of an electron beam enable the treatment of lesions close to the surface, while sparing the underlying tissues. In an extended source-to-surface (SSD) treatment with irregular field sizes defined by cerrobend cutouts, underdosage of the lateral tissue may occur due to reduced beam flatness and uniformity. To study the changes in the beam characteristics, the depth dose, beam profile, and isodose distributions were measured at different SSDs for regular 10 Χ 10 cm 2 and 15 Χ 15 cm 2 cone, and for irregular cutouts of field size 6.5 Χ 9 cm 2 a... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4096313 Mon, 18 Oct 2010 23:00:00 +0100 4096313 http://www.medworm.com/index.php?rid=4096312&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2010%2F35%2F4%2F202%2F71761 Girigesh Yadav, RS Yadav, Alok KumarJournal of Medical Physics 2010 35(4):202-206The purpose of this study was to find out the effect of various physical parameters on the skin and build-up doses of 15-MV photon beams. The effects of field dimensions, acrylic shadow tray, focus to-skin distance (FSD) on surface and buildup dose were determined for open, motorized 60° wedge (MW) and blocked fields. A 'Markus' plane parallel plate chamber was used for these measurements in an Elekta (6-15MV) linear accelerator. The surface dose for MW fields was lower than the dose for an open field, but the trend reversed for large fields and higher degree wedges. With the use of an acrylic shadow tray, the surface dose increased for all field sizes, but the increase was dominant f... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4096312 Mon, 18 Oct 2010 23:00:00 +0100 4096312 http://www.medworm.com/index.php?rid=4096311&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2010%2F35%2F4%2F197%2F71759 Michael S Gossman, Morris I BankJournal of Medical Physics 2010 35(4):197-201Dose-volume histograms provide key information to radiation oncologists when they assess the adequacy of a patient treatment plan in radiation therapy. It is important therefore that all clinically relevant data be accurate. In this article we present the first quality assurance routine involving a direct comparison of planning system results with the results obtained from independent hand calculations. Given a known three-dimensional (3-D) structure such as a parallelepiped, a simple beam arrangement, and known physics beam data, a time-efficient and reproducible method for verifying the accuracy of volumetric statistics (DVH) from a radiation therapy treatment planning system (TPS) can be employed rapidly, satis... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4096311 Mon, 18 Oct 2010 23:00:00 +0100 4096311 http://www.medworm.com/index.php?rid=4096310&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2010%2F35%2F4%2F189%2F71758 C Varatharaj, Eugenia Moretti, M Ravikumar, Maria Rosa Malisan, Sanjay S Supe, Renato PadovaniJournal of Medical Physics 2010 35(4):189-196Electronic portal imaging devices (EPIDs) are extensively used for obtaining dosimetric information of pre-treatment field verification and in-vivo dosimetry for intensity-modulated radiotherapy (IMRT). In the present study, we have implemented the newly developed portal dosimetry software using independent dose prediction algorithm EPIDose TM and evaluated this new tool for the pre-treatment IMRT plan quality assurance of Whole Pelvis with Simultaneous Integrated Boost (WP-SIB-IMRT ) of prostate cases by comparing with routine two-dimensional (2D) array detector system (MapCHECK TM ). We have investigated 104 split fields using g-distributions in terms... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4096310 Mon, 18 Oct 2010 23:00:00 +0100 4096310 http://www.medworm.com/index.php?rid=4096309&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Ftext.asp%3F2010%2F35%2F4%2F187%2F71756 AS PradhanJournal of Medical Physics 2010 35(4):187-188 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4096309 Mon, 18 Oct 2010 23:00:00 +0100 4096309 http://www.medworm.com/index.php?rid=4073157&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D3%3Bspage%3D181%3Bepage%3D181%3Baulast%3DHolla Raghavendra HollaJournal of Medical Physics 2010 35(3):181-181 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=4073157 Sat, 16 Oct 2010 16:17:48 +0100 4073157 http://www.medworm.com/index.php?rid=3786865&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D3%3Bspage%3D182%3Bepage%3D186%3Baulast%3DGanesh T GaneshJournal of Medical Physics 2010 35(3):182-186 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3786865 Mon, 26 Jul 2010 07:39:02 +0100 3786865 http://www.medworm.com/index.php?rid=3786864&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D3%3Bspage%3D181%3Bepage%3D181%3Baulast%3DHolla Raghavendra HollaJournal of Medical Physics 2010 35(3):181-181 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3786864 Mon, 26 Jul 2010 07:39:02 +0100 3786864 http://www.medworm.com/index.php?rid=3786863&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D3%3Bspage%3D174%3Bepage%3D180%3Baulast%3DPrionas This study aims to determine the precision (reproducibility) of volume assessment in routine clinical computed tomography (CT) using adrenal glands as surrogate tumors. Seven patients at our institution were identified retrospectively as having received numerous abdominal CT scans (average 13.1, range 5 to 20). The adrenal glands were used as surrogate tumors, assuming no actual volume change. Left and right adrenal gland volumes were assessed by hand segmentation for each patient scan. Over 1240 regions of interest were outlined in total. The reproducibility, expressed as the coefficient of variation (COV), was used to characterize measurement precision. The average volumes were 5.9 and 4.5 cm 3 for the left and right adrenal gland, respectively, with COVs of 17.8% and 18.9%... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3786863 Mon, 26 Jul 2010 07:39:02 +0100 3786863 http://www.medworm.com/index.php?rid=3786862&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D3%3Bspage%3D170%3Bepage%3D173%3Baulast%3DHerman This study aims at evaluating the impact of tissue heterogeneity corrections on dosimetry of stereotactic body radiation therapy treatment plans. Four-dimensional computed tomography data from 15 low stage non-small cell lung cancer patients was used. Treatment planning and dose calculations were done using pencil beam convolution algorithm of Varian Eclipse system with Modified Batho Power Law for tissue heterogeneity. Patient plans were generated with 6 MV co-planar non-opposing four to six field beams optimized with tissue heterogeneity corrections to deliver a prescribed dose of 60 Gy in three fractions to at least 95% of the planning target volume, keeping spinal cord dose <10 Gy. The same plans were then regenerated without heterogeneity correction by recalculating p... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3786862 Mon, 26 Jul 2010 07:39:02 +0100 3786862 http://www.medworm.com/index.php?rid=3786861&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D3%3Bspage%3D164%3Bepage%3D169%3Baulast%3DAttalla Ehab M Attalla, HS Abo-Elenein, H Ammar, Ismail El-DesokyJournal of Medical Physics 2010 35(3):164-169Dosimetric properties of virtual wedge (VW) and physical wedge (PW) in 6- and 10-MV photon beams from a Siemens ONCOR linear accelerator, including wedge factors, depth doses, dose profiles, peripheral doses, are compared. While there is a great difference in absolute values of wedge factors, VW factors (VWFs) and PW factors (PWFs) have a similar trend as a function of field size. PWFs have stronger depth dependence than VWF due to beam hardening in PW fields. VW dose profiles in the wedge direction, in general, match very well with those of PW, except in the toe area of large wedge angles with large field sizes. Dose profiles in the nonwedge direction show a significant reduction in PW fi... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3786861 Mon, 26 Jul 2010 07:39:02 +0100 3786861 http://www.medworm.com/index.php?rid=3786860&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D3%3Bspage%3D154%3Bepage%3D163%3Baulast%3DMinati This study examined the concentrations of brain metabolites visible to in-vivo 1 H-Magnetic Resonance Spectroscopy ( 1 H-MRS) at 1.5 T in a sample of 28 normal subjects. Quantitation was attempted for inositol compounds, choline units, total creatine and N-acetyl moieties, using open-source software. Six brain regions were considered: frontal and parietal white matter, medial temporal lobe, thalamus, pons and cerebellum. Absolute concentrations were derived using tissue water as an internal reference and using an external reference; metabolite signal intensity ratios with respect to creatine were also calculated. The inter-individual variability was smaller for absolute concentrations (internal reference) as compared to that for signal intensity ratios. Significant regional variability in ... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3786860 Mon, 26 Jul 2010 07:39:02 +0100 3786860 http://www.medworm.com/index.php?rid=3786859&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D3%3Bspage%3D151%3Bepage%3D153%3Baulast%3DAramburo Javier Morales Aramburo, Sigifredo Solano Gonzalez, Jorge Toledo ToledoJournal of Medical Physics 2010 35(3):151-153In biology, materials science, radiography quality control or film dosimetry in radiotherapy, a transmission densitometer is useful for measurements of optical density. The design proposed here is oriented to quality control in radiographic films. The instrument described here utilizes low-cost solid-state devices and is easy to construct. The use of 1-watt white light-emitting diode in this densitometer enables low power consumption and a cold light source. Moreover, the instrument does not need a reference light, which results in decreasing the number of parts and reducing the overall size of the apparatus. (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3786859 Mon, 26 Jul 2010 07:39:02 +0100 3786859 http://www.medworm.com/index.php?rid=3786858&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D3%3Bspage%3D144%3Bepage%3D150%3Baulast%3DSarkar Biplab Sarkar, Bhaswar Ghosh, Sriramprasath , Sukumaran Mahendramohan, Ayan Basu, Jyotirup Goswami, Amitabh RayJournal of Medical Physics 2010 35(3):144-150The study was aimed to compare accuracy of monitor unit verification in intensity modulated radiation therapy (IMRT) using 6 MV photons by three different methodologies with different detector phantom combinations. Sixty patients were randomly chosen. Zero degree couch and gantry angle plans were generated in a plastic universal IMRT verification phantom and 30Χ30Χ30 cc water phantom and measured using 0.125 cc and 0.6 cc chambers, respectively. Actual gantry and couch angle plans were also measured in water phantom using 0.6 cc chamber. A suitable point of measurement was chosen from the beam profile for each fi... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3786858 Mon, 26 Jul 2010 07:39:02 +0100 3786858 http://www.medworm.com/index.php?rid=3786857&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D3%3Bspage%3D137%3Bepage%3D143%3Baulast%3DPatel NP Patel, B Majumdar, V VijayanJournal of Medical Physics 2010 35(3):137-143The comparative dosimetry of GammaMed (GM) Plus high-dose rate brachytherapy source was performed by an experiment using 0.1-cc thimble ionization chamber and simulation-based study using EGSnrc code. In-water dose measurements were performed with 0.1-cc chamber to derive the radial dose function (r = 0.8 to 20.0 cm) and anisotropy function (r = 5.0 cm with polar angle from 10° to 170°). The nonuniformity correction factor for 0.1-cc chamber was applied for in-water measurements at shorter distances from the source. The EGSnrc code was used to derive the dose rate constant (L), radial dose function g L (r) and anisotropy function F(r, q) of GM Plus source. The dosimetric data derived using E... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3786857 Mon, 26 Jul 2010 07:39:02 +0100 3786857 http://www.medworm.com/index.php?rid=3786856&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D3%3Bspage%3D131%3Bepage%3D136%3Baulast%3DManoharan Sivasubramanian R Manoharan, R Rodney Rodriguez, Vidya S Bobba, Mukka ChandrashekarJournal of Medical Physics 2010 35(3):131-136Accelerated partial breast irradiation (APBI) with high dose rate (HDR) brachytherapy offers an excellent compact course of radiation due to its limited number of fractions for early-stage carcinoma of breast. One of the recent devices is SAVI (strut-adjusted volume implant), which has 6, 8 or 10 peripheral source channels with one center channel. Each channel can be differentially loaded. This paper focuses on the treatment planning, dosimetry and quality assurance aspects of HDR brachytherapy implant with GammaMed Plus HDR afterloader unit. The accelerated PBI balloon devices normally inflate above 35 cc range, and hence these balloon type devices cannot be acco... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3786856 Mon, 26 Jul 2010 07:39:02 +0100 3786856 http://www.medworm.com/index.php?rid=3786855&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D3%3Bspage%3D129%3Bepage%3D130%3Baulast%3DPaliwal Bhudatt R PaliwalJournal of Medical Physics 2010 35(3):129-130 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3786855 Mon, 26 Jul 2010 07:39:02 +0100 3786855 http://www.medworm.com/index.php?rid=3678436&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D2%3Bspage%3D65%3Bepage%3D72%3Baulast%3DGossman Michael S Gossman, Subhash C SharmaJournal of Medical Physics 2010 35(2):65-72The most common method to determine enhanced dynamic wedge factors begins with the use of segmented treatment tables. These segmental dose delivery values set as a function of upper jaw position are the backbone of a calculation process coined the "MU Fraction Approximation." Analytical and theoretical attempts have been made to extend and alter the mathematics for this approximation for greater accuracy. A set of linear equations in the form of a matrix are introduced here which correct one published extension of the MU Fraction Approximation as it applies to both symmetric and asymmetric photon fields. The matrix results are compared to data collected from a commissioned Varian Eclipse T... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3678436 Sun, 20 Jun 2010 07:22:29 +0100 3678436 http://www.medworm.com/index.php?rid=3631972&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D2%3Bspage%3D65%3Bepage%3D72%3Baulast%3DGossman Gossman Michael S, Sharma Subhash CJournal of Medical Physics 2010 35(2):65-72The most common method to determine enhanced dynamic wedge factors begins with the use of segmented treatment tables. These segmental dose delivery values set as a function of upper jaw position are the backbone of a calculation process coined the "MU Fraction Approximation." Analytical and theoretical attempts have been made to extend and alter the mathematics for this approximation for greater accuracy. A set of linear equations in the form of a matrix are introduced here which correct one published extension of the MU Fraction Approximation as it applies to both symmetric and asymmetric photon fields. The matrix results are compared to data collected from a commissioned Varian Eclip... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3631972 Sat, 05 Jun 2010 15:01:39 +0100 3631972 http://www.medworm.com/index.php?rid=3434868&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D2%3Bspage%3D128%3Bepage%3D128%3Baulast%3DRavichandran Ravichandran RJournal of Medical Physics 2010 35(2):128-128 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3434868 Sat, 03 Apr 2010 15:11:29 +0100 3434868 http://www.medworm.com/index.php?rid=3434867&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D2%3Bspage%3D123%3Bepage%3D127%3Baulast%3DGoharian Goharian M, Khan R. F. H.Journal of Medical Physics 2010 35(2):123-127For the management of mobile tumors, respiratory gating is the ideal option, both during imaging and during therapy. The major advantage of respiratory gating during imaging is that it is possible to create a single artifact-free CT data-set during a selected phase of the patient's breathing cycle. The purpose of the present work is to present a simple technique to measure the time delay during acquisition of a prospectively gated CT. The time delay of a Philips Brilliance BigBore™ (Philips Medical Systems, Madison, WI) scanner attached to a Varian Real-Time Position Management™ (RPM) system (Varian Medical Systems, Palo Alto, CA) was measured. Two methods were used to measure the... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3434867 Sat, 03 Apr 2010 15:11:29 +0100 3434867 http://www.medworm.com/index.php?rid=3434866&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D2%3Bspage%3D120%3Bepage%3D122%3Baulast%3DBakhtiari Bakhtiari M, Malhotra H, Jones M D, Chaudhary V, Walters J P, Nazareth DJournal of Medical Physics 2010 35(2):120-122We investigate the potential in using of using a graphics processor unit (GPU) for Monte-Carlo (MC)-based radiation dose calculations. The percent depth dose (PDD) of photons in a medium with known absorption and scattering coefficients is computed using a MC simulation running on both a standard CPU and a GPU. We demonstrate that the GPU's capability for massive parallel processing provides a significant acceleration in the MC calculation, and offers a significant advantage for distributed stochastic simulations on a single computer. Harnessing this potential of GPUs will help in the early adoption of MC for routine planning in a clinical environment. (Source: Journa... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3434866 Sat, 03 Apr 2010 15:11:29 +0100 3434866 http://www.medworm.com/index.php?rid=3434865&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D2%3Bspage%3D113%3Bepage%3D119%3Baulast%3DMurali This study shows that the prescribed dose covers 93 and 92% of the target volume in IMRT and HDR brachytherapy respectively. HDR brachytherapy delivers a much lesser dose to OAR, compared to the IMRT. For rectum, the V50 in IMRT is 34.0cc whilst it is 7.5cc in HDR brachytherapy. With the graphic optimization tool in HDR brachytherapy planning, the dose to urethra could be kept within 120% of the target dose. Hence it is concluded that HDR brachytherapy may be the choice of treatment for cancer of prostate in the early stage. (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3434865 Sat, 03 Apr 2010 15:11:29 +0100 3434865 http://www.medworm.com/index.php?rid=3434864&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D2%3Bspage%3D104%3Bepage%3D112%3Baulast%3DRanganathan This study aims to evaluate the performance of a new algorithm for optimization of beam weights in anatomy-based intensity modulated radiotherapy (IMRT). The algorithm uses a numerical technique called Gaussian-Elimination that derives the optimum beam weights in an exact or non-iterative way. The distinct feature of the algorithm is that it takes only fraction of a second to optimize the beam weights, irrespective of the complexity of the given case. The algorithm has been implemented using MATLAB with a Graphical User Interface (GUI) option for convenient specification of dose constraints and penalties to different structures. We have tested the numerical and clinical capabilities of the proposed algorithm in several patient cases in comparison with KonRad® inverse planni... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3434864 Sat, 03 Apr 2010 15:11:29 +0100 3434864 http://www.medworm.com/index.php?rid=3434863&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D2%3Bspage%3D100%3Bepage%3D103%3Baulast%3DVandana This study aims to check long term response stability of High Dose Rate (HDR) -1000 Plus well-type ionization chamber in terms of reference air kerma rate (RAKR) of a reference 137 Cs brachytherapy source and recommend an optimum frequency of recalibration. An HDR-1000 Plus well-type ionization chamber, a reference 137 Cs brachytherapy source (CDCSJ5), and a MAX-4000 electrometer were used in this study. The HDR-1000 Plus well-type chamber was calibrated in terms of reference air kerma rate by the Standards Laboratory of the International Atomic Energy Agency (IAEA), Vienna. The response of the chamber was verified at regular intervals over a period of eight years using the reference 137 Cs source. All required correction factors were applied in the calculation of the RAKR of the 137 Cs so... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3434863 Sat, 03 Apr 2010 15:11:29 +0100 3434863 http://www.medworm.com/index.php?rid=3434862&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D2%3Bspage%3D88%3Bepage%3D99%3Baulast%3DLakshminarayanan Lakshminarayanan Thilagam, Subbaiah K V, Thayalan K, Kannan S EJournal of Medical Physics 2010 35(2):88-99Brachytherapy treatment planning system (TPS) is necessary to estimate the dose to target volume and organ at risk (OAR). TPS is always recommended to account for the effect of tissue, applicator and shielding material heterogeneities exist in applicators. However, most brachytherapy TPS software packages estimate the absorbed dose at a point, taking care of only the contributions of individual sources and the source distribution, neglecting the dose perturbations arising from the applicator design and construction. There are some degrees of uncertainties in dose rate estimations under realistic clinical conditions. In this regard, an attempt is made to explore the suitability of point... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3434862 Sat, 03 Apr 2010 15:11:29 +0100 3434862 http://www.medworm.com/index.php?rid=3434861&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D2%3Bspage%3D81%3Bepage%3D87%3Baulast%3DShimozato Shimozato Tomohiro, Yasui Keisuke, Kawanami Ryota, Habara Kousaku, Aoyama Yuichi, Tabushi Katsuyoshi, Obata YasunoriJournal of Medical Physics 2010 35(2):81-87To investigate the effects of scattered radiation when a thin titanium plate (thickness, 0.05 cm) used for skull fixation in cerebral nerve surgery is irradiated by a 4-MV photon beam. We investigated the dose distribution of radiation inside a phantom that simulates a human head fitted with a thin titanium plate used for post-surgery skull fixation and compared the distribution data measured using detectors, obtained by Monte Carlo (MC) simulations, and calculated using a radiation treatment planning system (TPS). Simulations were shown to accurately represent measured values. The effects of scattered radiation produced by high-Z ma... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3434861 Sat, 03 Apr 2010 15:11:29 +0100 3434861 http://www.medworm.com/index.php?rid=3434860&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D2%3Bspage%3D73%3Bepage%3D80%3Baulast%3DJoshi Joshi Chandra P, Darko Johnson, Vidyasagar P B, Schreiner L JohnJournal of Medical Physics 2010 35(2):73-80Underdosing of treatment targets can occur in radiation therapy due to electronic disequilibrium around air-tissue interfaces when tumors are situated near natural air cavities. These effects have been shown to increase with the beam energy and decrease with the field size. Intensity modulated radiation therapy (IMRT) and tomotherapy techniques employ combinations of multiple small radiation beamlets of varying intensities to deliver highly conformal radiation therapy. The use of small beamlets in these techniques may therefore result in underdosing of treatment target in the air-tissue interfaces region surrounding an air cavity. This work was undertaken to investigate dose reduction... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3434860 Sat, 03 Apr 2010 15:11:29 +0100 3434860 http://www.medworm.com/index.php?rid=3434859&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D2%3Bspage%3D65%3Bepage%3D72%3Baulast%3DGossman Gossman Michael S, Sharma Subhash CJournal of Medical Physics 2010 35(2):65-72The most common method to determine enhanced dynamic wedge factors begins with the use of segmented treatment tables. These segmental dose delivery values set as a function of upper jaw position are the backbone of a calculation process coined the "MU Fraction Approximation." Analytical and theoretical attempts have been made to extend and alter the mathematics for this approximation for greater accuracy. A set of linear equations in the form of a matrix are introduced here which correct one published extension of the MU Fraction Approximation as it applies to both symmetric and asymmetric photon fields. The matrix results are compared to data collected from a commissioned Varian E... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3434859 Sat, 03 Apr 2010 15:11:29 +0100 3434859 http://www.medworm.com/index.php?rid=3434858&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D2%3Bspage%3D63%3Bepage%3D64%3Baulast%3DKurup Kurup GopalakrishnaJournal of Medical Physics 2010 35(2):63-64 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3434858 Sat, 03 Apr 2010 15:11:29 +0100 3434858 http://www.medworm.com/index.php?rid=3346103&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D1%3Bspage%3D57%3Bepage%3D58%3Baulast%3DSharma Sharma S DJournal of Medical Physics 2010 35(1):57-58 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3346103 Tue, 09 Mar 2010 17:11:40 +0100 3346103 http://www.medworm.com/index.php?rid=3346102&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D1%3Bspage%3D48%3Bepage%3D53%3Baulast%3DSenthilkumar This study assesses the level of terrestrial gamma radiation and associated dose rates from the naturally occurring radionuclides 232 Th, 238 U and 40 K in 10 soil samples collected from Thanjavur (Tamil Nadu, India) using g-ray spectrometry. The activity profile of radionuclides has clearly showed the existence of low level activity in Thanjavur. The geometric mean activity concentrations of 232 Th, 238 U and 40 K is 42.9±9.4 Bq.kg -1 , 14.7±1.7 Bq.kg -1 and 149.5±3.1 Bq.kg -1 respectively are derived from all the soil samples studied. The activity concentration of 232 Th, 238 U and 40 K in soil is due to the presence of metamorphic rocks like shale, hornblende-biotite gneiss and quartzofeldspathic gneiss in these areas. Gamma absorbed dose ... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3346102 Tue, 09 Mar 2010 17:11:40 +0100 3346102 http://www.medworm.com/index.php?rid=3346101&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D1%3Bspage%3D42%3Bepage%3D47%3Baulast%3DBahreyni In this study, we simulated a Siemens E.CAM SPECT system using SIMIND Monte Carlo program to acquire its experimental characterization in terms of energy resolution, sensitivity, spatial resolution and imaging of phantoms using 99m Tc. The experimental and simulation data for SPECT imaging was acquired from a point source and Jaszczak phantom . Verification of the simulation was done by comparing two sets of images and related data obtained from the actual and simulated systems. Image quality was assessed by comparing image contrast and resolution. Simulated and measured energy spectra (with or without a collimator) and spatial resolution from point sources in air were compared. The resulted energy spectra present similar peaks for the gamma energy of 99m Tc at 140 KeV. FWHM for the simul... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3346101 Tue, 09 Mar 2010 17:11:40 +0100 3346101 http://www.medworm.com/index.php?rid=3346100&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D1%3Bspage%3D33%3Bepage%3D41%3Baulast%3DAhmad This study was designed to investigate variation in Varian's Physical and Enhanced Dynamic Wedge Factors (WF) as a function of depth and field size. The profiles for physical wedges (PWs) and enhanced dynamic wedges (EDWs) were also measured using LDA-99 array and compared for confirmation of EDW angles at different depths and field sizes. WF measurements were performed in water phantom using cylindrical 0.66 cc ionization chamber. WF was measured by taking the ratio of wedge and open field ionization data. A normalized wedge factor (NWF) was introduced to circumvent large differences between wedge factors for different wedge angles. A strong linear dependence of PW Factor (PWF) with depth was observed. Maximum variation of 8.9% and 4.1% was observed for 60&... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3346100 Tue, 09 Mar 2010 17:11:40 +0100 3346100 http://www.medworm.com/index.php?rid=3346099&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D1%3Bspage%3D23%3Bepage%3D32%3Baulast%3DAyyangar Ayyangar Komanduri M, Kumar M Dinesh, Narayan Pradush, Jesuraj Fenedit, Raju M RJournal of Medical Physics 2010 35(1):23-32This investigation aims to design a practical multi-leaf collimator (MLC) system for the cobalt teletherapy machine and check its radiation properties using the Monte Carlo (MC) method. The cobalt machine was modeled using the BEAMnrc Omega-Beam MC system, which could be freely downloaded from the website of the National Research Council (NRC), Canada. Comparison with standard depth dose data tables and the theoretically modeled beam showed good agreement within 2%. An MLC design with low melting point alloy (LMPA) was tested for leakage properties of leaves. The LMPA leaves with a width of 7 mm and height of 6 cm, with tongue and groove of size 2 mm wide by 4 c... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3346099 Tue, 09 Mar 2010 17:11:40 +0100 3346099 http://www.medworm.com/index.php?rid=3346098&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D1%3Bspage%3D15%3Bepage%3D22%3Baulast%3DSahoo Sahoo S, Selvam T Palani, Vishwakarma R S, Chourasiya GJournal of Medical Physics 2010 35(1):15-22The reference medium for brachytherapy dose measurements is water. Accuracy of dose measurements of brachytherapy sources is critically dependent on precise measurement of the source-detector distance. A solid phantom can be precisely machined and hence source-detector distances can be accurately determined. In the present study, four different solid phantom materials such as polymethylmethacrylate (PMMA), polystyrene, Solid Water, and RW1 are modeled using the Monte Carlo methods to investigate the influence of phantom material on dose rate distributions of the new model of BEBIG 60 Co brachytherapy source. The calculated dose rate constant is 1.086 ± 0.06% cGy h&#x0026... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3346098 Tue, 09 Mar 2010 17:11:40 +0100 3346098 http://www.medworm.com/index.php?rid=3346097&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D1%3Bspage%3D3%3Bepage%3D14%3Baulast%3DSharma Sharma Neeraj, Aggarwal Lalit MJournal of Medical Physics 2010 35(1):3-14Accurate segmentation of medical images is a key step in contouring during radiotherapy planning. Computed topography (CT) and Magnetic resonance (MR) imaging are the most widely used radiographic techniques in diagnosis, clinical studies and treatment planning. This review provides details of automated segmentation methods, specifically discussed in the context of CT and MR images. The motive is to discuss the problems encountered in segmentation of CT and MR images, and the relative merits and limitations of methods currently available for segmentation of medical images. (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3346097 Tue, 09 Mar 2010 17:11:40 +0100 3346097 http://www.medworm.com/index.php?rid=3346096&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D1%3Bspage%3D1%3Bepage%3D2%3Baulast%3DPradhan Pradhan A SJournal of Medical Physics 2010 35(1):1-2 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3346096 Tue, 09 Mar 2010 17:11:40 +0100 3346096 http://www.medworm.com/index.php?rid=3148713&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D1%3Bspage%3D57%3Bepage%3D58%3Baulast%3DSharma SharmaSDJournal of Medical Physics 2010 35(1):57-58 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3148713 Thu, 07 Jan 2010 16:11:37 +0100 3148713 http://www.medworm.com/index.php?rid=3148712&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D1%3Bspage%3D54%3Bepage%3D56%3Baulast%3D Journal of Medical Physics 2010 35(1):54-56 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3148712 Thu, 07 Jan 2010 16:11:37 +0100 3148712 http://www.medworm.com/index.php?rid=3148711&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D1%3Bspage%3D48%3Bepage%3D53%3Baulast%3DSenthilkumar SenthilkumarB,DhavamaniV,RamkumarS,PhilominathanPJournal of Medical Physics 2010 35(1):48-53Thisstudyassessesthelevelofterrestrialgammaradiationandassociateddoseratesfromthenaturallyoccurringradionuclides<sup>232</sup>Th,<sup>238</sup>Uand<sup>40</sup>Kin10soilsamplescollectedfromThanjavur(TamilNadu,India)usingg-rayspectrometry.TheactivityprofileofradionuclideshasclearlyshowedtheexistenceoflowlevelactivityinThanjavur.Thegeometricmeanactivityconcentrationsof<sup>232</sup>Th,<sup>238</sup>Uand<sup>40</sup>Kis42.9±9.4Bq.kg<sup>-1</sup>,14.7±1.7Bq.kg<sup>-1</sup>and149.5±3.1Bq.kg<sup>-1</sup>respectivelyarederivedfromallthesoilsamplesstudied.Theactivityconcentr... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3148711 Thu, 07 Jan 2010 16:11:37 +0100 3148711 http://www.medworm.com/index.php?rid=3148710&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D1%3Bspage%3D42%3Bepage%3D47%3Baulast%3DBahreyni BahreyniToossiMT,IslamianJPirayesh,MomennezhadM,LjungbergM,NaseriSHJournal of Medical Physics 2010 35(1):42-47Inthisstudy,wesimulatedaSiemensE.CAMSPECTsystemusingSIMINDMonteCarloprogramtoacquireitsexperimentalcharacterizationintermsofenergyresolution,sensitivity,spatialresolutionandimagingofphantomsusing<sup>99m</sup>Tc.TheexperimentalandsimulationdataforSPECTimagingwasacquiredfromapointsourceandJaszczakphantom<b>.</b>Verificationofthesimulationwasdonebycomparingtwosetsofimagesandrelateddataobtainedfromtheactualandsimulatedsystems.Imagequalitywasassessedbycomparingimagecontrastandresolution.<b></b>Simulatedandmeasuredenergyspectra(withorwithoutacollimator)andspatialresolutionfrompointsourcesinairwerecompared.Theresultedenergyspectrapresentsimilarpeaksfor... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3148710 Thu, 07 Jan 2010 16:11:37 +0100 3148710 http://www.medworm.com/index.php?rid=3148709&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D1%3Bspage%3D33%3Bepage%3D41%3Baulast%3DAhmad AhmadMisbah,HussainAmjad,MuhammadWazir,RizviSyedQaisarAbbas,MatiullahJournal of Medical Physics 2010 35(1):33-41ThisstudywasdesignedtoinvestigatevariationinVarian'sPhysicalandEnhancedDynamicWedgeFactors(WF)asafunctionofdepthandfieldsize.Theprofilesforphysicalwedges(PWs)andenhanceddynamicwedges(EDWs)werealsomeasuredusingLDA-99arrayandcomparedforconfirmationofEDWanglesatdifferentdepthsandfieldsizes.WFmeasurementswereperformedinwaterphantomusingcylindrical0.66ccionizationchamber.WFwasmeasuredbytakingtheratioofwedgeandopenfieldionizationdata.Anormalizedwedgefactor(NWF)wasintroducedtocircumventlargedifferencesbetweenwedgefactorsfordifferentwedgeangles.AstronglineardependenceofPWFactor(PWF)withdepthwasobserved.Maximumvariationof8.9%and4.1%wasobservedfor60°PWwithdept... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3148709 Thu, 07 Jan 2010 16:11:37 +0100 3148709 http://www.medworm.com/index.php?rid=3148708&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D1%3Bspage%3D23%3Bepage%3D32%3Baulast%3DAyyangar AyyangarKomanduriM,KumarMDinesh,NarayanPradush,JesurajFenedit,RajuMRJournal of Medical Physics 2010 35(1):23-32Thisinvestigationaimstodesignapracticalmulti-leafcollimator(MLC)systemforthecobaltteletherapymachineandcheckitsradiationpropertiesusingtheMonteCarlo(MC)method.ThecobaltmachinewasmodeledusingtheBEAMnrcOmega-BeamMCsystem,whichcouldbefreelydownloadedfromthewebsiteoftheNationalResearchCouncil(NRC),Canada.Comparisonwithstandarddepthdosedatatablesandthetheoreticallymodeledbeamshowedgoodagreementwithin2%.AnMLCdesignwithlowmeltingpointalloy(LMPA)wastestedforleakagepropertiesofleaves.TheLMPAleaveswithawidthof7mmandheightof6cm,withtongueandgrooveofsize2mmwideby4cmheight,producedonly4%extraleakagecomparedto10cmheighttungstenleaves.Withfinite<sup>60</sup>Cosourcesize... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3148708 Thu, 07 Jan 2010 16:11:37 +0100 3148708 http://www.medworm.com/index.php?rid=3148707&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D1%3Bspage%3D15%3Bepage%3D22%3Baulast%3DSahoo SahooS,SelvamTPalani,VishwakarmaRS,ChourasiyaGJournal of Medical Physics 2010 35(1):15-22Thereferencemediumforbrachytherapydosemeasurementsiswater.Accuracyofdosemeasurementsofbrachytherapysourcesiscriticallydependentonprecisemeasurementofthesource-detectordistance.Asolidphantomcanbepreciselymachinedandhencesource-detectordistancescanbeaccuratelydetermined.Inthepresentstudy,fourdifferentsolidphantommaterialssuchaspolymethylmethacrylate(PMMA),polystyrene,SolidWater,andRW1aremodeledusingtheMonteCarlomethodstoinvestigatetheinfluenceofphantommaterialondoseratedistributionsofthenewmodelofBEBIG<sup>60</sup>Cobrachytherapysource.Thecalculateddoserateconstantis1.086±0.06%cGyh<sup>−1</sup>U<sup>−1</sup>forwater,PMMA,polystyrene,... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3148707 Thu, 07 Jan 2010 16:11:37 +0100 3148707 http://www.medworm.com/index.php?rid=3148706&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D1%3Bspage%3D3%3Bepage%3D14%3Baulast%3DSharma SharmaNeeraj,RayAmitK,ShuklaKK,SharmaShiru,PradhanSatyajit,SrivastvaArvind,AggarwalLalitMJournal of Medical Physics 2010 35(1):3-14Accuratesegmentationofmedicalimagesisakeystepincontouringduringradiotherapyplanning.Computedtopography(CT)andMagneticresonance(MR)imagingarethemostwidelyusedradiographictechniquesindiagnosis,clinicalstudiesandtreatmentplanning.Thisreviewprovidesdetailsofautomatedsegmentationmethods,specificallydiscussedinthecontextofCTandMRimages.ThemotiveistodiscusstheproblemsencounteredinsegmentationofCTandMRimages,andtherelativemeritsandlimitationsofmethodscurrentlyavailableforsegmentationofmedicalimages. (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3148706 Thu, 07 Jan 2010 16:11:37 +0100 3148706 http://www.medworm.com/index.php?rid=3148705&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2010%3Bvolume%3D35%3Bissue%3D1%3Bspage%3D1%3Bepage%3D2%3Baulast%3DPradhan PradhanASJournal of Medical Physics 2010 35(1):1-2 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=3148705 Thu, 07 Jan 2010 16:11:37 +0100 3148705 http://www.medworm.com/index.php?rid=2842137&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D4%3Bspage%3D227%3Bepage%3D229%3Baulast%3DGanesh GaneshTJournal of Medical Physics 2009 34(4):227-229 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2842137 Tue, 29 Sep 2009 18:26:18 +0100 2842137 http://www.medworm.com/index.php?rid=2842136&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D4%3Bspage%3D226%3Bepage%3D226%3Baulast%3DMackenzie MackenzieMarcJournal of Medical Physics 2009 34(4):226-226 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2842136 Tue, 29 Sep 2009 18:26:18 +0100 2842136 http://www.medworm.com/index.php?rid=2842135&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D4%3Bspage%3D223%3Bepage%3D225%3Baulast%3DRavichandran RavichandranR,BinukumarJP,DavisCA,ZahidAM,RajanBJournal of Medical Physics 2009 34(4):223-225Techniquesarebeingstandardizedinourdepartmentfortotalbodyirradiation(TBI)withsixMVphotonsinlinearacceleratorforpreconditioningtobonemarrowtransplantation(BMT).Individualizedshieldswithlowmeltingpointalloyaretobefabricatedforshieldingcriticalorganssuchaslungs,kidneysetc.Amethodtomountdiminisheddimensionofshieldsinatrayat3.75misdesignedinthedepartmentforateletreatmentdistanceoffourmeterswithmagnafieldwithAsimulatorimagetakenwiththepatient'smidplane(MP)atonemeterdistanceisusedtomarkthedimensionsoflung,scaleddownbyafactorof3.75/4.0.Theselungdimensionsarereprintedfromthedigitalsimulatorimageformakingtheshield.Themethodologyofthetechniqueusingdigitizedminificationinradiographyisthefirstofitskindto... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2842135 Tue, 29 Sep 2009 18:26:18 +0100 2842135 http://www.medworm.com/index.php?rid=2842134&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D4%3Bspage%3D217%3Bepage%3D222%3Baulast%3DLivingstone LivingstoneRoshanS,DinakaranPaulM,CherianRekhaS,EapenAnuJournal of Medical Physics 2009 34(4):217-222Computedtomography(CT)oftheabdomencontributesasubstantialamountofman-maderadiationdosetopatientsanduseofthismodalityisontheincrease.Thisstudyintendstocompareradiationdoseandimagequalityusingdosemodulationtechniquesandweight-basedprotocolexposureparametersforbiphasicabdominalCT.Usingasix-sliceCTscanner,aprospectivestudyof426patientswhounderwentabdominalCTexaminationswasperformed.Constanttubepotentialsof90kVand120kVwereusedforallarterialandportalvenousphaserespectively.Thetubecurrent-timeproductforweight-basedprotocolwasoptimizedaccordingtopatient'sbodyweight;thiswasautomaticallyselectedindosemodulations.Theeffectivedoseusingweight-basedprotocol,angularandz-axisdosemodulationwas11.3mSv... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2842134 Tue, 29 Sep 2009 18:26:18 +0100 2842134 http://www.medworm.com/index.php?rid=2842133&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D4%3Bspage%3D212%3Bepage%3D216%3Baulast%3DMondal MondalNagendraNathJournal of Medical Physics 2009 34(4):212-216ThisstudypresentsMonteCarloSimulation(MCS)resultsofdetectionefficiencies,spatialresolutionsandresolvingpowersofatime-of-flight(TOF)PETdetectorsystems.CeriumactivatedLutetiumOxyorthosilicate(Lu<sub>2</sub>SiO<sub>5</sub>:CeinshortLSO),BariumFluoride(BaF<sub>2</sub>)andBriLanCe380(CeriumdopedLanthanumtri-Bromide,inshortLaBr<sub>3</sub>)scintillationcrystalsarestudiedinviewoftheirgoodtimeandenergyresolutionsandshorterdecaytimes.TheresultsofMCSbasedonGEANTshowthatspatialresolution,detectionefficiencyandresolvingpowerofLSOarebetterthanthoseofBaF<sub>2</sub>andLaBr<sub>3</sub>,althoughitpossessesinferiortimeandenergyresolutions.Insteadoftheconventionalpositionrec... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2842133 Tue, 29 Sep 2009 18:26:18 +0100 2842133 http://www.medworm.com/index.php?rid=2842132&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D4%3Bspage%3D206%3Bepage%3D211%3Baulast%3DMarcu MarcuLoredanaG,BezakEvaJournal of Medical Physics 2009 34(4):206-211Headandneckcancerrepresentsachallengeforradiationoncologistsduetoacceleratedrepopulationofcancercellsduringtreatment.Thisstudyaimstosimulate,usingMonteCarlomethods,theresponseofavirtualheadandnecktumortobothconventionalandalteredfractionationschedulesinradiotherapywhenacceleratedrepopulationisconsidered.Althoughclinicaltrialsareindispensableforevaluationofnoveltherapeutictechniques,theyaretime-consumingprocesseswhichinvolvemanycomplexandvariablefactorsforsuccess.Modelscanovercomesomeofthelimitationsencounteredbytrialsastheyareabletosimulateinlesscomplexenvironmenttumorcellkineticsanddynamics,interactionprocessesbetweencellsandionizingradiationandtheiroutcome.Conventional,hyperfractionatedandacceleratedtreatmentscheduleshav... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2842132 Tue, 29 Sep 2009 18:26:18 +0100 2842132 http://www.medworm.com/index.php?rid=2842131&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D4%3Bspage%3D200%3Bepage%3D205%3Baulast%3DSankar SankarA,VelmuruganJJournal of Medical Physics 2009 34(4):200-205Inbreastradiotherapy,skinflashingoftreatmentfieldsisimportanttoaccountforintrafractionmovementsandsetuperrors.Thisstudycomparesthetwodifferentintensityextensionmethods,namely,VirtualBolusmethodandskinflashtoolmethod,toprovideskinflashinginintensitymodulatedtreatmentfields.Theimpactofthesetwodifferentintensityextensionmethodsonskindosewasstudiedbymeasuringtheentrancedoseofthetreatmentfieldsusingsemiconductordiodedetectors.Wefoundnosignificantdifferenceinentrancedoseduetodifferentmethodsusedforintensityextension.However,intheskinflashtoolmethod,selectionofappropriateparametersisimportanttogetoptimumfluenceextension. (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2842131 Tue, 29 Sep 2009 18:26:18 +0100 2842131 http://www.medworm.com/index.php?rid=2842130&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D4%3Bspage%3D194%3Bepage%3D199%3Baulast%3DSen SenAmarjit,WestMatthewKJournal of Medical Physics 2009 34(4):194-199Ahelicaltomotherapymachinecombinesastraight6MVlinearacceleratormountedonaringgantrywithCTtechnologyforimage-guidedintensity-modulatedradiationtherapy(IMRT)treatment.Afanbeamcreatedbythecollimatorandjawsproducesamaximumof40Χ5cm<sup>2</sup>fieldsizeattheisocenter.Thegantryandhencethefanbeamrotatesataconstantspeedwhilethecouchmoveslinearlyintothegantrybore,thusproducingahelicaldelivery.Thebeamismodulatedbya64-leafbinarymultileafcollimator(MLC),whichenablesIMRTtreatment.Thelinaccanbeoperatedatalowervoltage(3.5MV)anddoseratetoproducemegavoltageCTimages,whichareusedforimage-guidedpatientsetup.Wehaveinstalledtwosuchunitssince2004andtreatedmorethan2000patients.Themachinecomes"precommissioned"... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2842130 Tue, 29 Sep 2009 18:26:18 +0100 2842130 http://www.medworm.com/index.php?rid=2842129&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D4%3Bspage%3D191%3Bepage%3D193%3Baulast%3DKehwar KehwarTSJournal of Medical Physics 2009 34(4):191-193 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2842129 Tue, 29 Sep 2009 18:26:18 +0100 2842129 http://www.medworm.com/index.php?rid=2685069&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D3%3Bspage%3D129%3Bepage%3D132%3Baulast%3DNazareth NazarethDarylP,BrunnerStephen,JonesMatthewD,MalhotraHarishK,BakhtiariMohammadJournal of Medical Physics 2009 34(3):129-132Planningintensitymodulatedradiationtherapy(IMRT)treatmentinvolvesselectionofseveralangleparametersaswellasspecificationofstructuresandconstraintsemployedintheoptimizationprocess.Includingtheseparametersinthecombinatorialsearchspacevastlyincreasesthecomputationalburden,andthereforetheparameterselectionisnormallyperformedmanuallybyaclinician,basedonclinicalexperience.Wehaveinvestigatedtheuseofageneticalgorithm(GA)anddistributed-computingplatformtooptimizethegantryangleparametersandprovideinsightintoadditionalstructures,whichmaybenecessary,inthedoseoptimizationprocesstoproduceoptimalIMRTtreatmentplans.<b></b>ForanIMRTprostatepatient,weproducedthefirstgeneration... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2685069 Mon, 10 Aug 2009 11:50:37 +0100 2685069 http://www.medworm.com/index.php?rid=2685068&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D3%3Bspage%3D122%3Bepage%3D128%3Baulast%3DZaidi ZaidiHabib,PrasadRameshwarJournal of Medical Physics 2009 34(3):122-128Multimodalitymolecularimagingusinghighresolutionpositronemissiontomography(PET)combinedwithothermodalitiesisnowplayingapivotalroleinbasicandclinicalresearch.TheintroductionofcombinedPET/CTsystemsinclinicalsettinghasrevolutionizedthepracticeofdiagnosticimaging.Thecomplementaritybetweentheintrinsicallyalignedanatomic(CT)andfunctionalormetabolic(PET)informationprovidedina"one-stopshop"andthepossibilitytouseCTimagesforattenuationcorrectionofthePETdatahasbeenthedrivingforcebehindthesuccessofthistechnology.Ontheotherhand,combiningPETwithMagneticResonanceImaging(MRI)inasinglegantryistechnicallymorechallengingowingtothestrongmagneticfields.Nevertheless,significantprogresshasbeenmaderesultinginthedesignoffewpre... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2685068 Mon, 10 Aug 2009 11:50:37 +0100 2685068 http://www.medworm.com/index.php?rid=2685067&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D3%3Bspage%3D117%3Bepage%3D121%3Baulast%3DKaram KaramLisaRJournal of Medical Physics 2009 34(3):117-121Buildingonalonghistoryofprovidingphysicalmeasurementsandstandardsformedicalxraysandnuclearmedicineradionuclides,thelaboratoryhasexpandeditsfocustobettersupporttheextensiveuseofmedicalphysicsintheUnitedStatestoday,providingconfidenceinkeyresultsneededfordruganddevicedevelopmentandmarketing,therapyplanningandefficacyanddiseasescreening.Inparticular,tosupportmorequantitativemedicalimaging,thislaboratoryhasimplementedaprogramtoprovidekeymeasurementinfrastructuretosupportradiation-basedimagingthroughdevelopingstandard,benchmarkphantoms,whichcontainradioactivesourcescalibratedtonationalmeasurementstandards,toallowmorequantitativeimagingthroughtraceableinstrumentcalibrationforclinicaltrialsorpatientmanagement.Workingcloselywithcolleaguesatthe... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2685067 Mon, 10 Aug 2009 11:50:37 +0100 2685067 http://www.medworm.com/index.php?rid=2685066&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D3%3Bspage%3D108%3Bepage%3D116%3Baulast%3DPaliwal PaliwalBhudatt,TewatiaDineshJournal of Medical Physics 2009 34(3):108-116Duringthelastdecade,therehasbeenanexplosionofnewradiationtherapyplanninganddeliverytools.Wewentthrougharapidtransitionfromconventionalthree-dimensional(3D)conformalradiationtherapytointensity-modulatedradiationtherapy(IMRT)treatments,andadditionalnewtechniquesformotion-adaptiveradiationtherapyarebeingintroduced.Theseadvancespushthefrontiersinourefforttoprovidebetterpatientcare;andwiththeadditionofIMRT,temporaldimensionsaremajorchallengesfortheradiotherapypatientdosimetryanddeliveryverification.Advancedtechniquesarelesstoleranttopoorimplementationthanarestandardtechniques.Mis-administrationsaremoredifficulttodetectandcanpossiblyleadtopooroutcomesforsomepatients.Insteadofpresentingamanualonqualityassuranceforradiationth... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2685066 Mon, 10 Aug 2009 11:50:37 +0100 2685066 http://www.medworm.com/index.php?rid=2685065&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D3%3Bspage%3D107%3Bepage%3D107%3Baulast%3DPradhan PradhanASJournal of Medical Physics 2009 34(3):107-107 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2685065 Mon, 10 Aug 2009 11:50:37 +0100 2685065 http://www.medworm.com/index.php?rid=2667101&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D3%3Bspage%3D129%3Bepage%3D132%3Baulast%3DNazareth Nazareth Daryl P, Brunner Stephen, Jones Matthew D, Malhotra Harish K, Bakhtiari MohammadJournal of Medical Physics 2009 34(3):129-132Planning intensity modulated radiation therapy (IMRT) treatment involves selection of several angle parameters as well as specification of structures and constraints employed in the optimization process. Including these parameters in the combinatorial search space vastly increases the computational burden, and therefore the parameter selection is normally performed manually by a clinician, based on clinical experience. We have investigated the use of a genetic algorithm (GA) and distributed-computing platform to optimize the gantry angle parameters and provide insight into additional structures, which may be necessary, in the dose optimization process to pro... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2667101 Tue, 04 Aug 2009 12:29:05 +0100 2667101 http://www.medworm.com/index.php?rid=2667100&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D3%3Bspage%3D122%3Bepage%3D128%3Baulast%3DZaidi Zaidi Habib, Prasad RameshwarJournal of Medical Physics 2009 34(3):122-128Multimodality molecular imaging using high resolution positron emission tomography (PET) combined with other modalities is now playing a pivotal role in basic and clinical research. The introduction of combined PET/CT systems in clinical setting has revolutionized the practice of diagnostic imaging. The complementarity between the intrinsically aligned anatomic (CT) and functional or metabolic (PET) information provided in a "one-stop shop" and the possibility to use CT images for attenuation correction of the PET data has been the driving force behind the success of this technology. On the other hand, combining PET with Magnetic Resonance Imaging (MRI) in a single gantry is technicall... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2667100 Tue, 04 Aug 2009 12:29:05 +0100 2667100 http://www.medworm.com/index.php?rid=2667099&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D3%3Bspage%3D117%3Bepage%3D121%3Baulast%3DKaram Karam Lisa RJournal of Medical Physics 2009 34(3):117-121Building on a long history of providing physical measurements and standards for medical x rays and nuclear medicine radionuclides, the laboratory has expanded its focus to better support the extensive use of medical physics in the United States today, providing confidence in key results needed for drug and device development and marketing, therapy planning and efficacy and disease screening. In particular, to support more quantitative medical imaging, this laboratory has implemented a program to provide key measurement infrastructure to support radiation-based imaging through developing standard, benchmark phantoms, which contain radioactive sources calibrated to national measurement standards, to allow more quantitative imaging thro... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2667099 Tue, 04 Aug 2009 12:29:05 +0100 2667099 http://www.medworm.com/index.php?rid=2667098&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D3%3Bspage%3D108%3Bepage%3D116%3Baulast%3DPaliwal Paliwal Bhudatt, Tewatia DineshJournal of Medical Physics 2009 34(3):108-116During the last decade, there has been an explosion of new radiation therapy planning and delivery tools. We went through a rapid transition from conventional three-dimensional (3D) conformal radiation therapy to intensity-modulated radiation therapy (IMRT) treatments, and additional new techniques for motion-adaptive radiation therapy are being introduced. These advances push the frontiers in our effort to provide better patient care; and with the addition of IMRT, temporal dimensions are major challenges for the radiotherapy patient dosimetry and delivery verification. Advanced techniques are less tolerant to poor implementation than are standard techniques. Mis-administrations are more difficult to detect and ca... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2667098 Tue, 04 Aug 2009 12:29:05 +0100 2667098 http://www.medworm.com/index.php?rid=2667097&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D3%3Bspage%3D107%3Bepage%3D107%3Baulast%3DPradhan Pradhan A SJournal of Medical Physics 2009 34(3):107-107 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2667097 Tue, 04 Aug 2009 12:29:05 +0100 2667097 http://www.medworm.com/index.php?rid=2462823&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D2%3Bspage%3D80%3Bepage%3D86%3Baulast%3DArbabi Arbabi AzimJournal of Medical Physics 2009 34(2):80-86An extensive study of the human sternum has been carried out to obtain estimates of the omnidirectional path-length distributions and structural parameters for trabeculation and marrow spaces. Data for sternum samples have been collected, using an object plane scanning microscope. These data have been used to produce the omnidirectional path-length distributions and values of structural parameters for the whole sternum. For a typical adult man the mean trabecular and marrow space path lengths are 224 and 1364 µm, respectively. The percentage bone volume is 13.8 and the surface to volume ratio is 190 cm. Data on the structural variations within the whole sternum are presented. They show a percentage difference in bone volume betwe... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2462823 Mon, 08 Jun 2009 08:09:51 +0100 2462823 http://www.medworm.com/index.php?rid=2462822&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D2%3Bspage%3D73%3Bepage%3D79%3Baulast%3DKinhikar Kinhikar Rajesh A, Master Zubin, Dhote Dipak S, Deshpande Deepak DJournal of Medical Physics 2009 34(2):73-79A Helical Tomotherapy<sup> TM</sup> (HT) Hi-Art II (TomoTherapy, Inc., Madison, WI, USA) has been one of the important innovations to help deliver IMRT with image guidance. On-board, mega voltage computed tomography (MVCT) detectors are used for imaging and dosimetric purpose. The two objectives of this study are: (i) To estimate the dosimetric and general capability (TomoImage registration, reconstruction, contrast and spatial resolution, artifacts-free image and dose in TomoImage) of on-board MVCT detectors. (ii) To measure the dosimetric parameters (output and energy) following major repair. The MVCT detectors also estimated the rotational ... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2462822 Mon, 08 Jun 2009 08:09:51 +0100 2462822 http://www.medworm.com/index.php?rid=2462821&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D2%3Bspage%3D66%3Bepage%3D72%3Baulast%3DJothybasu This study is aimed to evaluate the impact of static and dynamic intensity modulated radiotherapy (IMRT) delivery techniques planned with Eclipse TPS on the integral dose to the healthy normal tissue surrounding the tumor-bearing area and to the volume receiving doses <5 Gy in patients with carcinoma nasopharynx treated with Simultaneous Integrated Boost IMRT (SIB-IMRT). Ten patients with carcinoma nasopharynx were chosen for this dosimetric study. IMRT plans were generated with 6X using dynamic multileaf collimator (DMLC) and static multileaf collimator (SMLC) with 5, 10 and 15 intensity levels (L). Integral dose, volume receiving 5 Gy, number of monitor units (MU) is compared against DMLC. The mean difference in the MU delivered per fraction between 5, 10 and 15 L SMLC and DMLC... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2462821 Mon, 08 Jun 2009 08:09:51 +0100 2462821 http://www.medworm.com/index.php?rid=2462820&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D2%3Bspage%3D63%3Bepage%3D65%3Baulast%3DRavichandran Ravichandran RJournal of Medical Physics 2009 34(2):63-65 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2462820 Mon, 08 Jun 2009 08:09:51 +0100 2462820 http://www.medworm.com/index.php?rid=2297691&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D1%3Bspage%3D59%3Bepage%3D59%3Baulast%3D Journal of Medical Physics 2009 34(1):59-59 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2297691 Sun, 29 Mar 2009 12:36:53 +0100 2297691 http://www.medworm.com/index.php?rid=2268316&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D1%3Bspage%3D58%3Bepage%3D58%3Baulast%3DSuntharalingam Suntharalingam NJournal of Medical Physics 2009 34(1):58-58 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2268316 Mon, 16 Mar 2009 17:54:06 +0100 2268316 http://www.medworm.com/index.php?rid=2268311&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D1%3Bspage%3D55%3Bepage%3D56%3Baulast%3DSharma Sharma S DJournal of Medical Physics 2009 34(1):55-56 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2268311 Mon, 16 Mar 2009 17:54:06 +0100 2268311 http://www.medworm.com/index.php?rid=2268305&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D1%3Bspage%3D52%3Bepage%3D54%3Baulast%3DGanesh Ganesh TJournal of Medical Physics 2009 34(1):52-54 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2268305 Mon, 16 Mar 2009 17:54:06 +0100 2268305 http://www.medworm.com/index.php?rid=2268297&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D1%3Bspage%3D48%3Bepage%3D51%3Baulast%3DRaghukumar This article describes the design and development of an inflatable balloon that can be used along with the applicator as a substitute for gauze packing. The balloon has two parts-the bladder part (B-part) and the rectum part (R-part), both of them are independently inflatable. The selection of the material, its width, length, and thickness are described. A mould/former for making the balloon was designed. Polished steel was used as the mould. This was dipped in specially prepared natural rubber latex (NRL) solution several times; the layers were dried and stripped to get the balloon. The composition of NRL and the compounding recipe of the latex are also described. Physical tests like tensile strength, elongation at break, bursting volume, and radiation attenuation caused by the balloon, w... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2268297 Mon, 16 Mar 2009 17:54:06 +0100 2268297 http://www.medworm.com/index.php?rid=2268285&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D1%3Bspage%3D43%3Bepage%3D47%3Baulast%3DBagavathiappan Bagavathiappan S, Saravanan T, Philip John, Jayakumar T, Raj Baldev, Karunanithi R, Panicker T.M.R, Korath M Paul, Jagadeesan KJournal of Medical Physics 2009 34(1):43-47Body temperature is a very useful parameter for diagnosing diseases. There is a definite correlation between body temperature and diseases. We have used Infrared Thermography to study noninvasive diagnosis of peripheral vascular diseases. Temperature gradients are observed in the affected regions of patients with vascular disorders, which indicate abnormal blood flow in the affected region. Thermal imaging results are well correlated with the clinical findings. Certain areas on the affected limbs show increased temperature profiles, probably due to inflammation and underlying venous flow changes. In general the temperature... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2268285 Mon, 16 Mar 2009 17:54:06 +0100 2268285 http://www.medworm.com/index.php?rid=2268272&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D1%3Bspage%3D37%3Bepage%3D42%3Baulast%3DBoujraf Boujraf Said, Summers Paul, Belahsen Faouzi, Prussmann Klaas, Kollias SpyrosJournal of Medical Physics 2009 34(1):37-42The choice of imaging parameters for functional MRI can have an impact on the accuracy of functional localization by affecting the image quality and the degree of blood oxygenation-dependent (BOLD) contrast achieved. By improving sampling efficiency, parallel acquisition techniques such as sensitivity encoding (SENSE) have been used to shorten readout trains in single-shot (SS) echo planar imaging (EPI). This has been applied to susceptibility artifact reduction and improving spatial resolution. SENSE together with single-shot spin-echo (SS-SE) imaging may also reduce off-resonance artifacts. The goal of this work was to investigate the BOLD response of a SENSE-adapted SE-... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2268272 Mon, 16 Mar 2009 17:54:06 +0100 2268272 http://www.medworm.com/index.php?rid=2268260&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D1%3Bspage%3D31%3Bepage%3D36%3Baulast%3DRavichandran The objective of the present study is to establish radiation standards for absorbed doses, for clinical high energy linear accelerator beams. In the nonavailability of a cobalt-60 beam for arriving at Nd, water values for thimble chambers, we investigated the efficacy of perspex mounted extrapolation chamber (EC) used earlier for low energy x-rays and beta dosimetry. Extrapolation chamber with facility for achieving variable electrode separations 10.5mm to 0.5mm using micrometer screw was used for calibrations. Photon beams 6 MV and 15 MV and electron beams 6 MeV and 15 MeV from Varian Clinac linacs were calibrated. Absorbed Dose estimates to Perspex were converted into dose to solid water for comparison with FC 65 ionisation chamber measurements in water. Measurements made during the peri... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2268260 Mon, 16 Mar 2009 17:54:06 +0100 2268260 http://www.medworm.com/index.php?rid=2268247&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D1%3Bspage%3D23%3Bepage%3D30%3Baulast%3DKinhikar Kinhikar Rajesh A, Jamema Swamidas V, Reenadevi, Pai Rajeshri, Zubin Master, Gupta Tejpal, Dhote Deepak S, Deshpande Deepak D, Shrivastava Shyam K, Sarin RajivJournal of Medical Physics 2009 34(1):23-30A Helical Tomotherapy (HT) Hi-Art II machine, Hi ART (TomoTherapy, Inc., Madison, WI, USA) was installed at our center in July 2007, and was the first machine in India. Image-guided HT is a new modality for delivering intensity modulated radiotherapy (IMRT). Dosimetric tests done include (a) primary beam alignment (b) secondary beam alignment (c) water tank measurements (profiles and depth doses) (d) dose rate measurements (e) IMRT verification, and (f) Mega voltage Computed Tomography (MVCT) dose. Primary and secondary beam alignment revealed an acceptable linear accelerator (linac) alignme... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2268247 Mon, 16 Mar 2009 17:54:06 +0100 2268247 http://www.medworm.com/index.php?rid=2268235&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D1%3Bspage%3D12%3Bepage%3D22%3Baulast%3DMuralidhar According to this study the dosimetric results using different algorithms led to significant variation and therefore care had to be taken while evaluating treatment plans. The choice of a dose calculation algorithm may in certain cases even influence clinical results. (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2268235 Mon, 16 Mar 2009 17:54:06 +0100 2268235 http://www.medworm.com/index.php?rid=2268223&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D1%3Bspage%3D4%3Bepage%3D11%3Baulast%3DToutaoui Toutaoui Abdelkader, Khelassi-Toutaoui Nadia, Brahimi Zakia, Chami Ahmed ChafikJournal of Medical Physics 2009 34(1):4-11In an early work we have demonstrated the possibility of using Monte Carlo generated pencil beams for 3D electron beam dose calculations. However, in this model the electron beam was considered as monoenergetic and the effects of the energy spectrum were taken into account by correction factors, derived from measuring central-axis depth dose curves. In the present model, the electron beam is considered as polyenergetic and the pencil beam distribution of a clinical electron beam, of a given nominal energy, is represented as a linear combination of Monte Carlo monoenergetic pencil beams. The coefficients of the linear combination describe the energy spectrum of the clinic... Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2268223 Mon, 16 Mar 2009 17:54:06 +0100 2268223 http://www.medworm.com/index.php?rid=2268214&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2009%3Bvolume%3D34%3Bissue%3D1%3Bspage%3D1%3Bepage%3D3%3Baulast%3DSharma Sharma S DJournal of Medical Physics 2009 34(1):1-3 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2268214 Mon, 16 Mar 2009 17:54:06 +0100 2268214 http://www.medworm.com/index.php?rid=2032733&cid=s_33842_75_f&fid=33842&url=http%3A%2F%2Fwww.jmp.org.in%2Farticle.asp%3Fissn%3D0971-6203%3Byear%3D2008%3Bvolume%3D33%3Bissue%3D4%3Bspage%3D178%3Bepage%3D178%3Baulast%3DIyer Iyer P SJournal of Medical Physics 2008 33(4):178-178 (Source: Journal of Medical Physics) Journal of Medical Physics journals http://www.medworm.com/rss/comments.php?id=2032733 Sat, 13 Dec 2008 08:23:33 +0100 2032733