A primer on theory and operation of linear accelerators in radiation therapy
Challapalli SrinivasJournal of Medical Physics 2019 44(4):298-299 (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - December 10, 2019 Category: Physics Authors: Challapalli Srinivas Source Type: research
Assessment of adult diagnostic reference levels for panoramic radiography in Tamil Nadu region
Conclusion: The present study suggests that further optimization can be achieved in many centers by the recruitment of professionally qualified radiographers and conducting periodic training programs on the optimization of exposure parameters. Considering this as the first study for the dental DRL assessment, further studies are suggested to establish national dental DRL in India. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - December 10, 2019 Category: Physics Authors: Amal Jose A Saravana Kumar KN Govindarajan B Devanand N Elango Source Type: research
A dosimetric analysis of the rectal doses in intracavitary brachytherapy of carcinoma cervix: A prospective study from a single institute
Conclusion: The modified ICRU rectal point is easier to visualize than ICRU 38 method (100% vs. 80%) for dosimetry, but it underestimates the rectal doses when compared to ICRU 38 rectal point. There needs to be a correction factor applied (25% in our study for Henschke applicator) when evaluating the rectal doses calculated by rectal wire method, to reduce the rectal toxicity. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - December 10, 2019 Category: Physics Authors: Aparna Suryadevara Anil Kumar Talluri Krishnam Raju Alluri E Vasundhara Sudhakar Kumar N V.N Madhusudhana Sresty Source Type: research
4 & #960; radiotherapy using a linear accelerator: A misnomer in violation of the solid geometric boundary conditions in three-dimensional Euclidean space
Conclusions: Present cantilever design of linear accelerator prevents achieving a 4π radian solid angle at any point in the patient. Even the most modern therapy machines like CyberKnife which has a robotic arm also cannot achieve 4π geometry. Maximum achievable solid angle under the highest allowable boundary condition(s) cannot exceed 2πc, which is restricted for only extremities such as foot and brain radiotherapy. For other parts of the body such as pelvis, thorax, and abdomen, the solid angle is reduced to 1/5th (maximum value) of the 4πc. To obtain a 4πc sol...
Source: Journal of Medical Physics - December 10, 2019 Category: Physics Authors: Biplab Sarkar Tharmarnadar Ganesh Anusheel Munshi Arjunan Manikandan Bidhu Kalyan Mohanti Source Type: research
The impact of positron emission tomography/computed tomography addition to contrast-enhanced computed tomography findings during radiation treatment planning of locally advanced carcinoma esophagus
Conclusions: PET-CT tremendously changes treatment plans by expanding the gross tumor volume and including regions which might otherwise have been missed on purely CT-based plans. Of the 50 patients, it changed the contouring and treatment planning of 35 patients and did not impact the remaining 15. Whether this translates into better long-term controls requires further validation by randomized controlled trials, which was not our present objective. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - December 10, 2019 Category: Physics Authors: Sharad Bhatnagar Shweta Sharma Manoj Semwal Sankalp Singh Source Type: research
Establishment of a new three-dimensional dose evaluation method considering variable relative biological effectiveness and dose fractionation in proton therapy combined with high-dose-rate brachytherapy
Conclusions: Our dose evaluation method can evaluate the EQD2LQLconsidering RBE changes in the dose distribution. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - December 10, 2019 Category: Physics Authors: Daisuke Kobayashi Tomonori Isobe Kenta Takada Yutaro Mori Hideyuki Takei Hiroaki Kumada Satoshi Kamizawa Tetsuya Tomita Eisuke Sato Hiroshi Yokota Takeji Sakae Source Type: research
Characterization of the mixed radiation field produced by carbon and oxygen ion beams of therapeutic energy: A Monte Carlo simulation study
Conclusions: This result coupled with the higher RBE shows that it may be possible to use a lower fluence of oxygen ions to achieve the same therapeutic dose in the patient as that obtained with carbon ion therapy. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - December 10, 2019 Category: Physics Authors: CK Ying David Bolst Anatoly Rosenfeld Susanna Guatelli Source Type: research
Dose shadowing and prosthesis involvement for megavoltage photon In vivo diode dosimetry
Conclusion: On the basis of accuracy requirements in radiotherapy noting that a small underdose to tumors could yield a decrease in the probability of tumor control, the diode-induced beam perturbations in combination with prosthesis involvement in the photon fields may affect treatment outcome, as there would be a reduction in the prescribed target dose during treatment delivery. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - December 10, 2019 Category: Physics Authors: Nicholas Ade Dete Van Eeden F C. P. Du Plessis Source Type: research
Experimental determination of radial dose function and anisotropy function of GammaMed Plus 192Ir high-dose-rate brachytherapy source in a bounded water phantom and its comparison with egs_brachy Monte Carlo simulation
Conclusion: Our experimental phantom size represents the average patient width of 30 cm; hence, results are closer to scattering conditions in clinical situations. The experimentally measured g(r) and F(r,θ) and egs_brachy MC calculations for bounded geometry are well in agreement within experimental uncertainties. Further, the confidence level of our comparative study is enhanced by validating the egs_brachy MC code for the unbounded phantom with respect to consensus data. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - December 10, 2019 Category: Physics Authors: Rekha Reddy Buchapudi Ravikumar Manickam Varatharaj Chandaraj Source Type: research
Estimation of backscatter from internal shielding in electron beam radiotherapy using Monte Carlo simulations (EGSnrc) and Gafchromic film measurements
Conclusions: This study provides an important clinical data to design internal shielding at the local clinical setup and confirms applicability of MC simulations in backscatter dose calculations at interfaces where physical measurements are difficult to perform. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - December 10, 2019 Category: Physics Authors: Sukhvir Singh Manoj Kumar Semwal CP Bhatt Source Type: research
Simple electronic portal imager-based pretreatment quality assurance using Acuros XB: A feasibility study
Conclusion: EPID dosimetry produced an inferior result due to no heterogeneity corrections for sites such as the lung and esophagus. Incorporating TPS-based heterogeneity correction improved the EPID dosimetry result for those sites with large heterogeneity. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - December 10, 2019 Category: Physics Authors: Arjunan Manikandan Sureka Chandra Sekaran Biplab Sarkar Sujatha Manikandan Source Type: research
The physics of CT dosimetry: CTDI and beyond
Gurpreet SinghJournal of Medical Physics 2019 44(3):228-229 (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - September 12, 2019 Category: Physics Authors: Gurpreet Singh Source Type: research
Evaluation and validation of IBA I & #39;MatriXX array for patient-specific quality assurance of tomotherapy & #174;
N V. N Madhusudhana Sresty, A Krishnam Raju, B Nagarjuna Reddy, VC Sahithya, Yakub Mohmd, G Deleep Kumar, T Anil Kumar, Tasneem Rushdi, S Aparna, G Durga Prasad, Harjot Kaur BajwaJournal of Medical Physics 2019 44(3):222-227TomoTherapy® is a modern radiation treatment technique in which intensity-modulated radiation therapy (IMRT) is delivered in helical fashion. A two-dimensional (2D) array which has been existing for IMRT patient-specific quality assurance (PSQA) verifications for many years is I'MatriXX. Our objectives were to validate this I'MatriXX and to evaluate it for different pat...
Source: Journal of Medical Physics - September 12, 2019 Category: Physics Authors: N V. N Madhusudhana Sresty A Krishnam Raju B Nagarjuna Reddy VC Sahithya Yakub Mohmd G Deleep Kumar T Anil Kumar Tasneem Rushdi S Aparna G Durga Prasad Harjot Kaur Bajwa Source Type: research
Evaluation of healthy tissue dose at different regions between volumetric-modulated arc therapy and intensity-modulated radiation therapy plans in the treatment of various cancers
Conclusions: VMAT plan can reduce the risk of secondary malignancy while treating different sites of cancer. VMAT is the most appropriate technique than IMRT, especially in the treatment of large tumor volume. Special attention has to be given, especially while treating women and children. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - September 12, 2019 Category: Physics Authors: Jayapalan Krishnan Suresh Rao Sanath Hegde Jayarama Shetty Source Type: research
Calibration of gafchromic EBT film using the Microtek ScanMaker 9800XL plus flatbed scanner with a modified one red-channel after three-channel method
Conclusion: The proposed technique allows the use of the three-channel method to calibrate film using a Microtek 9800XL+ scanner. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - September 12, 2019 Category: Physics Authors: Liyun Chang Sheng-Yow Ho Hueisch-Jy Ding Shyh-An Yeh Pang-Yu Chen Source Type: research
