In this work, the use of gold and gold alloy plaques is proposed for the first time, to reduce the dose to healthy organs in brachytherapy with Ir-192 sources. For dose simulations in tumour and healthy tissue, the MCNPX Monte Carlo code was used. The radiation source implemented in those simulations was benchmarked with well-known TG-43 criteria of dose rate constant, air-kerma strength, radial dose function, and 2D anisotropy function. For various arrangements of iridium sources and plaques of gold and gold alloy of various thicknesses, the dose distributions in an esophagus tumour and in surrounding healthy organs were simulated. The results showed that while the dose to the tumour is not much affected by the presence of gold plaques with a thickness of 3.5 mm in an optimized ¹⁹²Ir sources’ configuration, a relative reduction in average organ dose of 64%, 65%, 73%, 67%, and 35% was observed, for esophagus, thyroid, heart, stomach, and liver, respectively. Moreover, it was found that a gold plaque leads to smaller doses to healthy organs than a gold alloy plaque. It is concluded that gold plaques can be used to improve the treatment of esophageal cancer by HDR brachytherapy and to protect surrounding non-target organs.

在这项工作中，首次建议使用金和金合金斑块，以减少使用Ir-192来源进行近距离放射治疗对健康器官的剂量。为了在肿瘤和健康组织中模拟剂量，使用了MCNPX蒙特卡洛代码。在那些模拟中实现的辐射源以众所周知的TG-43剂量率常数，空气比释动能强度，径向剂量函数和2D各向异性函数的标准为基准。对于各种厚度的铱源以及金和金合金的不同厚度的斑块，模拟了食道肿瘤和周围健康器官的剂量分布。结果表明，在优化的^192中，虽然对肿瘤的剂量不受厚度为3.5 mm的金斑存在的影响不大在来源的配置中，食道，甲状腺，心脏，胃和肝脏的平均器官剂量相对减少了64％，65％，73％，6​​7％和35％。此外，已经发现，与金合金斑块相比，金斑块对健康器官的剂量较小。结论是，金牌匾可用于通过HDR近距离放射治疗改善食道癌的治疗并保护周围的非靶器官。