A generic TG-186 shielded applicator for commissioning model-based dose calculation algorithms for high-dose-rate Ir-192 brachytherapy
PurposeA joint working group was created by the American Association of Physicists in Medicine (AAPM), the European Society for Radiotherapy and Oncology (ESTRO), and the Australasian Brachytherapy Group (ABG) with the charge, among others, to develop a set of well-defined test case plans and perform calculations and comparisons with model-based dose calculation algorithms (MBDCAs). Its main goal is to facilitate a smooth transition from the AAPM Task Group No. 43 (TG-43) dose calculation formalism, widely being used in clinical practice for brachytherapy, to the one proposed by Task Group No. 186 (TG-186) for MBDCAs. To do so, in this work a hypothetical, generic high-dose rate (HDR) Ir-19…
SU-F-T-63: Dosimetric Relevance of the Valencia and Leipzig HDR Applicators Plastic Cap
Purpose: Utilization of HDR brachytherapy treatment of skin lesions using collimated applicators, such as the Valencia or Leipzig is increasing. These applicators are made of cup-shaped tungsten material in order to focalize the radiation into the lesion and to protect nearby tissues. These applicators have an attachable plastic cap that removes secondary electrons generated in the applicator and flattens the treatment surface. The purpose of this study is to examine the dosimetric impact of this cap, and the effect if the cap is not placed during the HDR fraction delivery. Methods: Monte Carlo simulations have been done using the code Geant4 for the Valencia and Leipzig applicators. Dose r…
Implementation and Validation of an End-to-End Commissioning Process for Model-Based Dose Calculation Algorithms in Brachytherapy
WE-C-141-01: Research and Relevance of Brachytherapy Dose Calculation Advancements
Research and Relevance of Brachytherapy Dose Calculation Advancements Organizer: Mark J. Rivard Moderator: Geoffrey S. Ibbott Speakers: Facundo Ballester, Asa Carlsson Tedgren, Firas Mourtada Brachytherapy dosimetry is undergoing a renaissance with the scrutiny of the AAPM TG‐43 dose calculation formalism and comparisons with alternate approaches such as the Monte Carlo method, the grid‐based Boltzmann solvers, and the collapsed‐cone technique. Treatment planning systems (TPS) using these more advanced, model‐based dose calculation algorithms (MBDCAs) are now available for clinical use. However, their accuracy and the preferred method for their use have not been established. Thus, it is imp…
SU-E-T-509: DICOM Test Case Plans for Model-Based Dose Calculations Methods in Brachytherapy
Purpose: The TG‐186 report provides guidance to early adopters of model‐based dose calculation algorithms (MBDCAs) for brachytherapy. A charge of the AAPM‐ESTRO Working Group on MBDCA is to develop well‐defined test case plans, available as references for the software commissioning process to be performed by end‐users. The aim of this work is to develop test case plans for a generic HDR 192 Ir source alone and in combination with a vaginal cylinder applicator with 180° tungsten‐alloy shielding in a DICOM‐based water phantom. Methods: A DICOM CT dataset was created with a 30 cm diameter water sphere surrounded by air. The voxel size was 1.33×1.33×1.33 mm3 for evaluating absorbed dose rate (c…
A generic high-dose rate192Ir brachytherapy source for evaluation of model-based dose calculations beyond the TG-43 formalism
Purpose: In order to facilitate a smooth transition for brachytherapy dose calculations from the American Association of Physicists in Medicine (AAPM) Task Group No. 43 (TG-43) formalism to model-b ...