Abstract：
Identifying the organs and tissues at risk from internal radiation exposure caused by radiopharmaceuticals requires determining the absorbed dose. The absorbed dose for radiopharmaceuticals is calculated by multiplying cumulated activity in source organs by the S-value, a crucial quantity that connects the energy deposited in the target organ and the emitting source one. It is defined as the ratio of absorbed energy in the target organ per unit of mass and unit of nuclear transition in the source organ. In this study, we used a new Geant4-based code called DoseCalcs to estimate the S-values for four positron-emitting radionuclides ([Formula: see text]C, [Formula: see text]N, [Formula: see text]O, and [Formula: see text]F) using decay and energy data from International Commission on Radiological Protection (ICRP) Publication 107. Twenty-three regions were simulated as radiation sources in the ICRP voxelized adult model developed in ICRP Publication 110. The Livermore physics packages were tailored to radionuclide photon mono-energy and [Formula: see text]-mean energy. The estimated S-values based on [Formula: see text]-mean energy show good agreement with those in the OpenDose data whose values were calculated using the full [Formula: see text] spectrum. The results provide new S-values data for selected source regions; hence, they could be used for comparison and adult-patient dose estimation.
摘要：
识别处于由放射性药物引起的内部辐射暴露的风险中的器官和组织需要确定吸收剂量。放射性药物的吸收剂量是通过将源器官中的累积活性乘以S值计算的。连接靶器官和发射源之一中沉积的能量的关键数量。它被定义为每单位质量的目标器官中吸收的能量与来源器官中的核过渡单位的比率。在这项研究中,我们使用了一种新的基于Geant4的代码，称为DoseCalcs，以估计四个发射正电子的放射性核素的S值（[公式：见文本]C，[公式:见正文]N,[公式:见正文]O,and[Formula:seetext]F)usingdecayandenergydatafromInternationalCommissiononRadiologicalProtection(ICRP)Publication107.在ICRP出版物110中开发的ICRP体素化成人模型中，模拟了23个区域作为辐射源。利弗莫尔物理软件包是针对放射性核素光子单能和[公式：见正文]平均能量而定制的。基于[公式:参见文本]-平均能量的估计S值显示与OpenDose数据中的那些具有良好的一致性,所述OpenDose数据的值是使用完整的[公式:参见文本]谱计算的。结果为选定的源区提供了新的S值数据；因此，它们可用于比较和成人-患者剂量估算.
