Development and validation of a GEANT4 radiation transport code for CT dosimetry

Area of Science:

• Medical Physics
• Radiological Sciences
• Computational Physics

Background:

• Accurate radiation dose simulation is crucial for pediatric CT examinations.
• GEANT4 Monte Carlo toolkit offers a powerful platform for radiation transport modeling.
• Validation of simulations with physical dosimetry is essential for clinical application.

Purpose of the Study:

• To validate a GEANT4-based Monte Carlo simulation for pediatric CT radiation transport.
• To compare simulated dosimetry data with physical measurements using ionization chambers and OSL dosimeters.

Main Methods:

• Developed a GEANT4 Monte Carlo code for pediatric CT simulations.
• Performed physical dosimetry measurements using a 100-mm CT pencil ionization chamber and OSL dosimeters.
• Utilized standard 16-cm head and 32-cm body acrylic phantoms for measurements.
• Derived photon-fluence calibration factors from ionization chamber measurements at 100 and 120 kVp.

Main Results:

• Simulated and measured CTDI values showed excellent agreement, with an overall average difference of 6%.
• Both ionization chamber and OSL dosimeter measurements provided reliable data for simulation validation.
• The study confirmed the accuracy of the developed Monte Carlo simulation for pediatric CT dosimetry.

Conclusions:

• The GEANT4 Monte Carlo simulation is a validated and accurate tool for simulating radiation transport in pediatric CT examinations.
• The findings support the use of this simulation for optimizing radiation dose in pediatric imaging.
• This work contributes to the reliable dosimetry of pediatric CT procedures.