Comparative GEANT۴-based Monte Carlo dosimetry of I-۱۲۵ and Pd-۱۰۳ in soft tissue, blood, and adipose tissue

This study presents a GEANT۴-based Monte Carlo dosimetry comparison of clinically realistic I-۱۲۵ (Amersham OncoSeed ۶۷۰۲) and Pd-۱۰۳ (BEBIG IsoSeed) brachytherapy sources in adipose tissue, soft tissue, and blood. The simulation model was rigorously validated against AAPM TG-۴۳ consensus data, showing excellent agreement in dose rate constants and radial dose functions. The model was thoroughly tested and validated to ensure its robustness and accuracy. Results demonstrated that tissue composition significantly alters dose distributions compared to water. Adipose tissue permitted the deepest penetration, while blood showed the strongest attenuation. The results indicated that I-۱۲۵, align with its lower average energy, produced a broader dose distribution than Pd-۱۰۳. Conversely, ۱۰۳Pd exhibited a steeper dose gradient, confining energy closer to the source. These findings underscore the critical importance of incorporating both tissue-specific composition and the full photon energy spectrum into brachytherapy treatment planning to optimize dose delivery for personalized patient care ultimately optimizing clinical outcomes.

کلیدواژه ها:

GEANT۴ ، Monte Carlo simulation ، I-۱۲۵ ، Pd-۱۰۳ ، Dosimetry ، Tissue composition