Repeatability of small field output factor measurements with various detectors
Zakithi Lungile Mpumelelo Msimang, Debbie van der Merwe, Nkosingiphile MaphumuloJournal of Medical Physics 2021 46(1):47-51There are well established dosimetry reference standards for broad beams; however, there are no reference standards that can be used for both broad and small fields. The variation of the equivalent square fields and field output factors in small static photon fields when using a synthetic diamond, an electron diode, and ionization chambers (pin point, semiflex, and liquid filled) was investigated over time. Data from this study were compared to the data from other hospitals in the country and standard ...
Source: Journal of Medical Physics - May 5, 2021 Category: Physics Authors: Zakithi Lungile Mpumelelo Msimang Debbie van der Merwe Nkosingiphile Maphumulo Source Type: research
Use of multiple-tube phantom: A method to globally correct native T1 relaxation time inhomogeneity in dedicated molecular magnetic resonance breast coil
Conclusion: Inhomogeneity in the native T1 value exists in dedicated mMR breast coil, and significant improvement can be achieved using specially designed external phantom with multiple tubes. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - May 5, 2021 Category: Physics Authors: Pradeep Singh Negi Shashi Bhushan Mehta Amarnath Jena Source Type: research
Establishment and dissemination of radiological standards in the field of diagnostic radiology in India
Conclusion: The air kerma rates agreed within ±1% and are within the overall standard uncertainty of both the chambers at the time of the comparison. Dissemination to the users in the field of diagnostic radiology in the country has been carried out by calibrating their ionization chambers and solid-state detector-based instruments against the DFAIC. The methodology followed to standardize the beams using DFAIC and calibration of dosimeters is presented in this work. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - May 5, 2021 Category: Physics Authors: Vinatha Sumanth Panyam Sougata Rakshit Sanjay Daga Dhole Bhushankumar Jagnnath Patil Amaren Prasanna Das Greeshma Anantharaman Kossery Sathian Vilippalil Probal Chaudhury Source Type: research
Probability distribution of pixel intensities of ebt3 films and its application in the correction of uncertainty budget
Conclusion: In the case of the limited number of measurements of a quantity, the SU values must be corrected using the “t” value to get the correct CSU. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - May 5, 2021 Category: Physics Authors: Rahul Kumar Chaudhary Munir Pathan Rajesh Kumar SD Sharma BK Sapra Source Type: research
Dosimetric comparison of robotic and linear accelerator multi-leaf collimator-based stereotactic radiosurgery for arteriovenous malformation
Conclusion: Our study shows CK collimator (IRIS and FIXED) could be able to treat brain AVMs in any size. Linac MLC-based SRS has some limitations in terms of conformity and low-dose spillage, and advantages like reduced treatment time and MU. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - May 5, 2021 Category: Physics Authors: Venkatesan Kaliyaperumal Susan Abraham Maragatha Veni Susovan Banerjee S Tamilselvan Deepak Gupta K Dayanithi D Manigandan Saumyaranjan Mishra Shyam Singh Bisht Tejinder Kataria Source Type: research
Dosimetric evaluation of simplified knowledge-based plan with an extensive stepping validation approach in volumetric-modulated arc therapy-stereotactic body radiotherapy for lung cancer
Conclusions: The simplified KBPs with limited number of structures and without planner intervention were clinically acceptable in the dosimetric parameters for lung VMAT-SBRT planning. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - May 5, 2021 Category: Physics Authors: Yutaro Wada Hajime Monzen Mikoto Tamura Masakazu Otsuka Masahiro Inada Kazuki Ishikawa Hiroshi Doi Kiyoshi Nakamatsu Yasumasa Nishimura Source Type: research
Use of a checklist approach on a telecobalt in an attempt to reduce human errors in radiotherapy delivery and improve therapeutic ratio
Conclusions: The development and use of the checklist has helped in reducing errors and also improving workflow in our department. It is recommended to utilize such physical checklists in all radiotherapy centers with telecobalt machines. The success of the checklist depends upon leadership, teamwork, acceptance of a need to inculcate a “safety culture,” with voluntary error-reporting and a willingness to learn from such errors. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - May 5, 2021 Category: Physics Authors: Hari Mukundan Sankalp Singh Nishant Lohia Manoj Kumar Semwal Vijendra Kumar Sharad Bhatnagar Arti Sarin Gaurav Trivedi Source Type: research
The computed tomography handbook: Optimizing Protocols for Todays & #39; feature-rich scanners
Roshan Samuel LivingstoneJournal of Medical Physics 2020 45(4):261-263 (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - February 2, 2021 Category: Physics Authors: Roshan Samuel Livingstone Source Type: research
Effect of three-dimensional detector orientation on small-field output factors
Zakithi Lungile Mpumelelo Msimang, Debbie Van Der Merwe, Nkosingiphile MaphumuloJournal of Medical Physics 2020 45(4):256-260The IAEA TRS 483 has recommended that the orientation for cylindrical ionization chambers be perpendicular to the beam for small-field output factor (OF) measurements. The recommendation was based on the unavailability of field output correction factor data for measurements using parallel orientation at the time of publication. Two three-dimensional (3D) air ionization chambers were used to perform measurements in parallel and perpendicular orientations and compared to data determined using a PTW 310...
Source: Journal of Medical Physics - February 2, 2021 Category: Physics Authors: Zakithi Lungile Mpumelelo Msimang Debbie Van Der Merwe Nkosingiphile Maphumulo Source Type: research
Texture analysis on ultrasound: The effect of time gain compensation on histogram metrics and gray-level matrices
Conclusions: TGC settings must be accounted for when carrying out further TA studies. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - February 2, 2021 Category: Physics Authors: Giulio Vara Arianna Rustici Andrea Sechi Cristina Mosconi Vincenzo Lucidi Rita Golfieri Source Type: research
Assessment of single- and double-strand breaks in DNA induced by auger electrons of radioisotopes used in diagnostic and therapeutic applications
Conclusion: The results showed that the geometric shape of the sugar-phosphate groups may have a significant effect on the number of single-strand breaks (SSBs) and double-strand breaks (DSBs) of the DNA molecule. Among the most widely used diagnostic radioisotopes, 201Tl and 125I, had the greatest impact on the number of SSBs and DSBs, respectively, while therapeutic radioisotope of 131I almost had no effect, therapeutic radioisotope of 211At had the moderate effect on the number of breaks in the DNA chain. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - February 2, 2021 Category: Physics Authors: Mahdi Seifi Moradi Babak Shirani Bidabadi Source Type: research
Evaluation of optimal combination of planning parameters (Field width, pitch, and modulation factor) in helical tomotherapy for bilateral breast cancer
Conclusions: On the basis of our analysis, a plan with FW 5 cm, pitch 0.215, and MF 2.5 can be considered as an optimal combination of planning parameters for bilateral breast irradiation in HT technique. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - February 2, 2021 Category: Physics Authors: CA Muthuselvi TK Bijina A Pichandi Source Type: research
Is synchronous bilateral breast irradiation using flattening filter-free beam-based volumetric-modulated arc therapy beneficial ? A dosimetric study
Conclusion: The planning objective parameters achieved using FFF-based VMAT showed that FFF can also be used clinically to treat bilateral breast carcinomas and the low-dose lung volumes were still lesser with FFF-VMAT plans than FF-VMAT. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - February 2, 2021 Category: Physics Authors: Jagadheeskumar Nagaraj K Veluraja Source Type: research
Spatial mesh-based surface source model for the electron contamination of an 18 MV photon beams
Conclusion: Despite the simplification in the source model, the electron contamination is still accurate to within 1.5%. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - February 2, 2021 Category: Physics Authors: Ahad Ollah Ezzati Matthew T Studenski Masuomeh Gohari Source Type: research
Estimation of skin doses for retrofit prototype multileaf collimators designed for telecobalt therapy machine
Conclusions: From the measurements, it can be concluded that there is good skin sparing even at close distance to the MLCs. The skin dose is <50% for SSDs >65 cm. A minimum gap of 5 cm is required to produce acceptable skin dose. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - February 2, 2021 Category: Physics Authors: Akula Roopa Rani Komanduri Ayyangar AR Reddy Ayyalasomayajula Anil Kumar Pal Reddy Yadagiri Reddy Source Type: research
