RapidBrachyTG43: A Geant4‐based TG‐43 parameter and dose calculation module for brachytherapy dosimetry

Abstract

AbstractBackgroundThe AAPM TG‐43U1 formalism remains the clinical standard for dosimetry of low‐ and high‐energy ‐emitting brachytherapy sources. TG‐43U1 and related reports provide consensus datasets of TG‐43 parameters derived from various published measured data and Monte Carlo simulations. These data are used to perform standardized and fast dose calculations for brachytherapy treatment planning.PurposeMonte Carlo TG‐43 dosimetry parameters are commonly derived to characterize novel brachytherapy sources. RapidBrachyTG43 is a module of RapidBrachyMCTPS, a Monte Carlo‐based treatment planning system, designed to automate this process, requiring minimal user input to prepare Geant4‐based Monte Carlo simulations for a source. RapidBrachyTG43 may also perform a TG‐43 dose to water‐in‐water calculation for a plan, substantially accelerating the same calculation performed using RapidBrachyMCTPS's Monte Carlo dose calculation engine.MethodsTG‐43 parameters , , , and were calculated using three commercial source models, one each of I, Ir, and Co, and were benchmarked to published data. TG‐43 dose to water was calculated for a clinical breast brachytherapy plan and was compared to a Monte Carlo dose calculation with all patient tissues, air, and catheters set to water.ResultsTG‐43 parameters for the three simulated sources agreed with benchmark datasets within tolerances specified by the High Energy Brachytherapy Dosimetry working group. A gamma index comparison between the TG‐43 and Monte Carlo dose‐to‐water calculations with a dose difference and difference to agreement criterion of 1%/1 mm yielded a 98.9% pass rate, with all relevant dose volume histogram metrics for the plan agreeing within 1%. Performing a TG‐43‐based dose calculation provided an acceleration of dose‐to‐water calculation by a factor of 165.ConclusionsDetermination of TG‐43 parameter data for novel brachytherapy sources may now be facilitated by RapidBrachyMCTPS. These parameter datasets and existing consensus or published datasets may also be used to determine the TG‐43 dose for a plan in RapidBrachyMCTPS.