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

Area of Science:

• Medical Physics
• Radiation Oncology
• Computational Dosimetry

Background:

• The AAPM TG-43U1 formalism is the clinical standard for brachytherapy dosimetry.
• Consensus datasets of TG-43 parameters are derived from measurements and Monte Carlo simulations for treatment planning.

Purpose of the Study:

• To automate the derivation of Monte Carlo TG-43 dosimetry parameters for novel brachytherapy sources using RapidBrachyTG43.
• To accelerate TG-43 dose-to-water calculations for treatment plans.

Main Methods:

• Calculated TG-43 parameters for I-125, Ir-192, and Co-60 sources using commercial models.
• Benchmarked calculated parameters against published data.
• Performed TG-43 dose-to-water calculations for a breast brachytherapy plan and compared with Monte Carlo simulations.

Main Results:

• Simulated TG-43 parameters agreed with benchmark data within specified tolerances.
• Gamma index analysis showed a 98.9% pass rate for TG-43 vs. Monte Carlo dose-to-water calculations (1%/1 mm criteria).
• TG-43 dose calculation was 165 times faster than the Monte Carlo engine.

Conclusions:

• RapidBrachyMCTPS facilitates the determination of TG-43 parameter data for new brachytherapy sources.
• TG-43 dose calculations for treatment plans can be efficiently performed using RapidBrachyMCTPS with existing datasets.