A comparison between GATE4 results and MCNP4B published data for internal radiation dosimetry

Area of Science:

• Medical Physics
• Nuclear Medicine
• Computational Dosimetry

Background:

• The GATE (Geant4 Application Tomography Emission) toolkit is designed for nuclear medicine, including internal dosimetry.
• Validation of GATE/GEANT with anthropomorphic phantoms for internal dosimetry is lacking.
• Comparison with established codes like MCNP4B is crucial for its adoption.

Purpose of the Study:

• To compare internal dose calculations from GATE/GEANT with MCNP4B.
• To assess the performance of GATE/GEANT using an anthropomorphic voxel phantom.
• To validate GATE/GEANT for radionuclide dosimetry in nuclear medicine.

Main Methods:

• Utilized the Zubal phantom, modeling a typical adult male.
• Simulated uniform activity distribution in organs like the liver, kidneys, and lungs.
• Performed Monte Carlo simulations using GATE/GEANT for photon and electron energies, calculating specific absorbed fractions (SAF) and S-factors.

Main Results:

• GATE/GEANT showed a +2.7% higher photon SAF for self-absorption and -2.9% lower for cross-absorption compared to MCNP4B.
• Differences were more pronounced in paired organs, especially the lungs.
• Lung SAF values at 200 and 500 keV were notably higher with MCNP4B than GATE.

Conclusions:

• Results from GATE/GEANT and MCNP4B show acceptable agreement, validating GATE/GEANT.
• This study supports the use of GATE/GEANT as a reliable code for nuclear medicine dosimetry.
• Further validation of GATE/GEANT for internal dosimetry applications is recommended.