A new Iridium-192 seed for brachytherapy is under development. Specific dose rate contribution by two different factors were evaluated: the effect from movement of the core in the free space within the seed and the effect of the end-weld thickness variation. Both were investigated through use of the Monte Carlo radiation transport code MCNP6 and an in-house routine programmed with MATLAB. Differences greater than 15% compared to results from the nominal seed were found near the source, indicating a significant dose variation.

中文翻译：

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蒙特卡罗模拟评估自由空间和端部焊缝厚度变化对新型 Ir-192 近距离放射治疗源剂量率的影响

一种用于近距离放射治疗的新型 Iridium-192 种子正在开发中。评估了两个不同因素对特定剂量率的贡献：芯在种子内自由空间中移动的影响和端焊缝厚度变化的影响。通过使用蒙特卡罗辐射传输代码 MCNP6 和使用 MATLAB 编程的内部程序对两者进行了研究。在源附近发现了与标称种子结果相比的 15% 以上的差异，表明剂量变化很大。