Development and validation of RAYDOSE: a Geant4-based application for molecular radiotherapy

Area of Science:

• Medical Physics
• Radiological Sciences
• Computational Imaging

Background:

• Accurate patient-specific dosimetry is crucial for radionuclide medical therapy (MRT).
• Monte Carlo simulations offer high precision for dose calculations but require robust validation.
• Integrating multi-modal imaging data (CT, PET) enhances personalized treatment planning.

Purpose of the Study:

• To develop and validate RAYDOSE, a Monte Carlo application for generating patient-specific 3D dose maps.
• To assess the accuracy of RAYDOSE against established software and experimental measurements.
• To establish RAYDOSE as a reliable platform for MRT treatment planning and research.

Main Methods:

• Developed RAYDOSE, a Monte Carlo simulation application utilizing CT for patient geometry and PET for radionuclide kinetics.
• Validated dose calculations using a NEMA phantom, comparing S values and total doses against OLINDA/EXM.
• Compared RAYDOSE simulations with thermoluminescent dosimeter (TLD) measurements in a custom heterogeneous phantom for iodine-131 (131I) gamma radiation.

Main Results:

• RAYDOSE demonstrated agreement within 2% with OLINDA/EXM reference data for sphere sizes >2.8 cm.
• Simulations using RAYDOSE showed agreement within 5% compared to TLD measurements for 131I.
• The application successfully models patient geometry and radionuclide distribution for dose mapping.

Conclusions:

• RAYDOSE is a validated Monte Carlo-based application for patient-specific 3D dose map generation.
• The application shows high accuracy when compared to reference software and experimental phantom data.
• RAYDOSE serves as a valuable multi-modal platform for radionuclide therapy planning and research.