Monte Carlo evaluation of dose distribution in Gamma Cell 220 irradiation

Dose Distribution in gamma irradiation is an important aspect of the process. Accurate distribution analysis performed on gamma irradiators can be done by several methods, one of which is Monte Carlo simulation. This work aims to analyze the distribution of the Gamma Cell 220 irradiator. Simulation of a PMMA cylinder as a holder at the reference position, evaluation with and without a 2 cm lead (Pb) attenuator, and evaluation of dose mapping in three horizontal planes and one vertical plane. The simulation results show a relative agreement between alanine measurements and simulations of 4%. The dose uniformity ratio (DUR) with the central horizontal plane (height 5–15 cm) shows the most uniform distribution (DUR ≈ 1.31). The Pb attenuator is effective in reducing the dose rate, but the simulation results show dominant Compton scattering, resulting in increased central dose accumulation and slightly higher DUR values. These findings indicate that control and dose reduction in Pb are possible but have an impact on homogeneity because they change the dynamics of photon interactions in the irradiation space. The combined simulation and experimental approach demonstrated here provides a reliable framework for optimizing low-dose gamma irradiation processes. The insights gained support improved dose control for applications requiring precise irradiation.