Photon and Neutron Dose Estimation Using Monte Carlo Simulation in TrueBeam's Room

Soai Dang Quoc; Toshioh Fujibuchi; Hiroyuki Arakawa; Keisuke Hamada

doi:10.4103/jmp.jmp_70_24

Photon and Neutron Dose Estimation Using Monte Carlo Simulation in TrueBeam's Room

J Med Phys. 2024 Jul-Sep;49(3):473-479. doi: 10.4103/jmp.jmp_70_24. Epub 2024 Sep 21.

Authors

Soai Dang Quoc¹, Toshioh Fujibuchi², Hiroyuki Arakawa², Keisuke Hamada^{1

3}

Affiliations

¹ Department of Health Sciences, Division of Medical Quantum Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
² Department of Health Sciences, Division of Medical Quantum Science, Faculty of Medical Sciences, Kyushu University, Fukuoka, Japan.
³ Department of Radiological Technology, National Hospital Organization Kyushu Cancer Center, Fukuoka, Japan.

Abstract

Purpose: The distribution of neutron ambient dose equivalent within the TrueBeam 10 MV photon chamber was investigated.

Materials and methods: The research used particle and heavy ion transport code system (PHITS) code and JENDL-5.0 to simulate the neutron ambient dose equivalent on and around TrueBeam's head. The simulated results were compared with the measured results using CR-39 detectors when TrueBeam radiated 5000 monitor units of 10 MV photons with field sizes 20 cm × 20 cm and 0.5 cm × 0.5 cm.

Results: Out of field size, the neutron ambient dose equivalents of the 0.5 cm × 0.5 cm field size are higher than those values of the 20 cm × 20 cm field size from 4% to 30%. The differences between the simulated value and the measured value of the neutron ambient dose equivalents at all points out of field size are smaller than 20%.

Conclusion: The neutron ambient dose equivalents, simulated with PHITS and JENDL-5.0, are satisfied with the measured neutron ambient dose equivalent.

Keywords: Ambient dose equivalent; Monte Carlo; particle and heavy ion transport code system; photoneutron; radiotherapy.