Centro de Tecnologia das Radiações, Instituto de Pesquisas Energéticas e Nucleareas, São Paulo, SP, Brazil.
Universidade de São Paulo, São Paulo, SP, Brazil.
Biomed Phys Eng Express. 2024 Nov 5;11(1). doi: 10.1088/2057-1976/ad8acc.
. To estimate dose rates delivered by using radioactiveAu nanoparticles for prostate cancer nanobrachytherapy, identifying contribution by photons and electrons emmited from the source.. Utilizingmodels, two different anatomical representations were compared: a mathematical model and a unstructured mesh model based on the International Commission on Radiological Protection (ICRP) Publication 145 phantom. Dose rates by activity were calculated to the tumor and nearby healthy tissues, including healthy prostate tissue, urinary bladder wall and rectum, using Monte Carlo code MCNP6.2.. Results indicate that both models provide dose rate estimates within the same order of magnitude, with the mathematical model overestimating doses to the prostate and bladder by approximately 20% compared to the unstructured mesh model. The discrepancies for the tumor and rectum were below 4%. Photons emmited from the source were defined as the primary contributors to dose to other organs, while 97.9% of the dose to the tumor was due to electrons emmited from the source.. Our findings emphasize the importance of model selection in dosimetry, particularly the advantages of using realistic anatomical phantoms for accurate dose calculations. The study demonstrates the feasibility and effectiveness ofAu nanoparticles in achieving high dose concentrations in tumor regions while minimizing exposure to surrounding healthy tissues. Beta emissions were found to be predominantly responsible for tumor dose delivery, reinforcing the potential ofAu nanoparticles in localized radiation therapy. We advocate for using realistic body phantoms in further research to enhance reliability in dosimetry for nanobrachytherapy, as the field still lacks dedicated protocols.
. 为了估算放射性 Au 纳米颗粒用于前列腺癌近距离纳米治疗的剂量率，需要确定来自源的光子和电子的贡献。.. 利用模型，比较了两种不同的解剖表示形式：基于国际辐射防护委员会（ICRP）出版物 145 体模的数学模型和非结构化网格模型。使用蒙特卡罗代码 MCNP6.2 计算了肿瘤和附近健康组织（包括健康前列腺组织、膀胱壁和直肠）的活度剂量率。.. 结果表明，两种模型都提供了数量级相同的剂量率估计值，与非结构化网格模型相比，数学模型高估了前列腺和膀胱的剂量约 20%。肿瘤和直肠的差异低于 4%。源发射的光子被定义为对其他器官剂量的主要贡献者，而源发射的电子对肿瘤的剂量贡献了 97.9%。.. 我们的研究结果强调了在剂量学中模型选择的重要性，特别是使用真实解剖体模进行准确剂量计算的优势。该研究表明 Au 纳米颗粒在实现肿瘤区域高剂量浓度的同时最大限度地减少对周围健康组织的暴露方面具有可行性和有效性。β发射被发现主要负责肿瘤剂量传递，这增强了 Au 纳米颗粒在局部放射治疗中的潜力。我们主张在进一步的研究中使用真实的身体体模，以提高纳米近距离治疗剂量学的可靠性，因为该领域仍然缺乏专门的协议。
