Incidence of suboptimal applicator placement and the resulting dosimetric impact in image-based intracavitary brachytherapy
Conclusion: In order to achieve better local control and to decrease doses to OAR, it is important to perform a technically accurate applicator placement. A cost-effective, real-time image guidance modality like ultrasound is recommended for all insertions to ensure optimal applicator insertion. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - September 26, 2018 Category: Physics Authors: Ramya Rangarajan Source Type: research
Comparison of measured and Monte Carlo calculated dose distributions from indigenously developed 6 MV flattening filter free medical linear accelerator
Conclusions: A Monte Carlo model of indigenous FFF linac (6 MV) has been developed and benchmarked against the measured data. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - September 26, 2018 Category: Physics Authors: Bibekananda Mishra Subhalaxmi Mishra T Palani Selvam ST Chavan SN Pethe Source Type: research
Voxel based BED and EQD2Evaluation of the radiotherapy treatment plan
Conclusion: BED-and EQD2-colorwash and iso-effective curves along with BED and EQD2dose volume histograms provide superior radiobiological information as compared to those of physical doses. This study provides supplementary recipes of radiobiological doses along with the physical doses which are useful for the evaluation of complex radiotherapy treatment plan of the patients. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - September 26, 2018 Category: Physics Authors: Gaganpreet Singh Arun S Oinam Rose Kamal Bhumika Handa Vivek Kumar Bhavana Rai Source Type: research
A dose falloff gradient study in RapidArc planning of lung stereotactic body radiation therapy
Conclusions: Dose falloff outside PTV has been studied as a function of radial distance and ascertained by intermediate dose to normal lung. DFG can serve as a complementary plan quality metric. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - September 26, 2018 Category: Physics Authors: Ganesh Narayanasamy Dharmin Desai Sanjay Maraboyina Jose Penagaricano Robert Zwicker Ellis Lee Johnson Source Type: research
Erratum: Magnetic resonance imaging for adaptive cobalt tomotherapy: A proposal
Journal of Medical Physics 2018 43(2):146-146 (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - June 18, 2018 Category: Physics Source Type: research
Documentation of a new intracavitary applicator for transrectal hyperthermia designed for prostate cancer cases: A phantom study
Vassilis Kouloulias, Aggeliki Nikolakopoulou, Irene Karanasiou, Christos Antypas, Christina Armpilia, Nikolaos UzunoglouJournal of Medical Physics 2018 43(2):141-145Concerning clinical trials, intracavitary hyperthermia has already shown antitumor activity and has a potential role in the treatment of prostate cancer. The aim of this study was to document a new intracavitary applicator operating at 433 MHz, designed for transrectal hyperthermia, as well as to assess the specific absorption rate (SAR) distributions in terms of temperature measurements in a soft-tissue phantom. The microwave applicator consists of a dipole-ty...
Source: Journal of Medical Physics - June 18, 2018 Category: Physics Authors: Vassilis Kouloulias Aggeliki Nikolakopoulou Irene Karanasiou Christos Antypas Christina Armpilia Nikolaos Uzunoglou Source Type: research
Interfraction dose variations in organs at risk during CT-based high-dose-rate brachytherapy in locally advanced carcinoma cervix: An early experience of a tertiary care Center
Conclusion: We did not find variations in the OAR doses when each fraction was planned and treated individually. However, we found that if a single plan is used to treat subsequent fractions, OAR doses may exceed tolerance in about 30% of the cases. We believe that a larger sample size with improved compliance of bladder and bowel protocols would be needed to arrive at definitive conclusions. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - June 18, 2018 Category: Physics Authors: Neelam Sharma Manoj K Semwal Abhishek Purkayastha Source Type: research
Dosimetric, radiobiological and secondary cancer risk evaluation in head-and-neck three-dimensional conformal radiation therapy, intensity-modulated radiation therapy, and volumetric modulated arc therapy: A phantom study
Jalil Ur Rehman, Muhammad Isa, Nisar Ahmad, Gulfam Nasar, H M. Noor Ul Huda Khan Asghar, Zaheer Abbas Gilani, James C. L. Chow, Muhammad Afzal, Geoffrey S IbbottJournal of Medical Physics 2018 43(2):129-135This analysis estimated secondary cancer risks after volumetric modulated arc therapy (VMAT) and compared those risks to the risks associated with other modalities of head-and-neck (H&N) radiotherapy. Images of H&N anthropomorphic phantom were acquired with a computed tomography scanner and exported via digital imaging and communications in medicine (DICOM) standards to a treatment planning system. ...
Source: Journal of Medical Physics - June 18, 2018 Category: Physics Authors: Jalil Ur Rehman Muhammad Isa Nisar Ahmad Gulfam Nasar H M. Noor Ul Huda Khan Asghar Zaheer Abbas Gilani James C. L. Chow Muhammad Afzal Geoffrey S Ibbott Source Type: research
Validation of delivery consistency for intensity-modulated radiation therapy and volumetric-modulated arc therapy plans
Wui Ann Woon, Paul B Ravindran, Piyasiri Ekayanake, Yivonne Yih Fang LimJournal of Medical Physics 2018 43(2):119-128The delivery consistency of a Varian Edge linear accelerator over the entire course of treatment for nasopharynx carcinoma (NPC) and prostate cancer intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) treatment plans was investigated using four different approaches. Three NPCs and three prostate plans were delivered in 34 and 29 consecutive days, respectively, using a Varian Edge equipped with a 120 high-definition (HD) multileaf collimator (MLC). All deliveries were meas...
Source: Journal of Medical Physics - June 18, 2018 Category: Physics Authors: Wui Ann Woon Paul B Ravindran Piyasiri Ekayanake Yivonne Yih Fang Lim Source Type: research
Patient-Specific quality assurance protocol for volumetric modulated arc therapy using dose volume histogram
This study has demonstrated the integration of DVH metrics into a VMAT PSQA protocol to provide clinically meaningful results that complement point dose and gamma index measurements. 3DVH should be regarded as an investigative tool that may be useful in diagnosing the cause of failed plans since it allows dose errors to be related to the patient anatomy. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - June 18, 2018 Category: Physics Authors: Christopher Low Warren Toye Peter Phung Christopher Huston Source Type: research
A practical method to optimize quality assurance results of arc therapy plans in beam modeling
This study addressed the systematic issue of beam modeling and developed a practical method to determine the optimal DLG value for a beam model. Several complex VMAT plans were selected for the quality assurance analysis using the variable DLG values. The results of three-dimensional (3D) Gamma analysis as a function of the DLG at 3%/3 mm, 2%/2 mm, and 1%/1 mm criteria were fitted by a polynomial curve. The DLG value corresponding to the maximum Gamma passing rate for each polynomial fitting function was derived, and the average was calculated to be the optimal DLG value for each model. The...
Source: Journal of Medical Physics - June 18, 2018 Category: Physics Authors: Jinyu Xue Hesheng Wang David Barbee Matthew Schmidt Indra J Das Source Type: research
A homogeneous water-equivalent anthropomorphic phantom for dosimetric verification of radiotherapy plans
This study demonstrates that a heterogeneous patient can be converted to a water phantom with comparable dosimetric characteristics and disagreements restricted to the lung area for both modulated and open beams. Potential sources of error include the dWEcalculation and TPS dose computation. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - June 18, 2018 Category: Physics Authors: Manikandan Arjunan Sureka Chandra Sekaran Biplab Sarkar Sujatha Manikandan Source Type: research
Validation of a software upgrade in a monte carlo treatment planning system by comparison of plans in different versions
Conclusion: For lung VMAT plans, in both versions, SU could be accepted up to 3% per plan with reduced tCT without compromising plan quality and deliverability by accepting variations in point dose and an inhomogeneous dose within the target. The plan quality of Monaco™V5.10.02 was similar to Monaco™TPS-V5.11 except for tCT. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - June 18, 2018 Category: Physics Authors: P Mohandass D Khanna D Manigandan Narendra Kumar Bhalla Abhishek Puri Source Type: research
Radiation dose measurements in a 256-slice computed tomography scanner
Conclusion: Although the IEC method is the easiest to use compared to the TG111 and direct DPI measurement method, it underestimates dose indices by about 20%. CTDIs displayed on the GE scanner are lower than those measured in this study by up to 38%. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - June 18, 2018 Category: Physics Authors: Victor J Weir Jie Zhang Source Type: research
Dosimetric comparison of irregular surface compensator and field-in-field for whole breast radiotherapy
Conclusions: The ISC technique is preferred over the FIF technique. (Source: Journal of Medical Physics)
Source: Journal of Medical Physics - June 18, 2018 Category: Physics Authors: Nao Kuwahata Hideki Fujita Hideaki Yamanishi Eiichiro Okazaki Haruyuki Fukuda Source Type: research
