Nuclear medicine is the second largest source of medical radiation exposure to the general population after computed tomography imaging. Informed decisions regarding the use of nuclear medicine procedures require a better understanding of the magnitude of radiation dose and associated health risks. However, existing model-based organ dose estimation tools rely on simplified human anatomy models or commercial programs. Therefore, we developed a publicly-available dose calculation tool based on more sophisticated human anatomy models. We calculated a comprehensive library of photon and electron specific absorbed fractions (SAF) for multiple combinations of source and target regions within a series of pediatric and adult computational human phantoms matching the International Commission on Radiological Protection (ICRP)'s reference data, combined with a Monte Carlo radiation transport code. Then, we derived a library of S values from these SAFs and the nuclear decay data from ICRP Publication 107. Finally, we created a graphical user interface, named National Cancer Institute Dosimetry System for Nuclear Medicine (NCINM), to facilitate the dosimetry process. Approximately 13 million S values were derived from 2 million SAFs computed in this work. Comprehensive comparisons were conducted at different steps of the dosimetry chain with data available in software OLINDA/EXM 1.0 and IDAC 2.1. For instance, median ratios of photon self-absorption SAFs available from OLINDA/EXM 1.0 and IDAC 2.1 to those calculated in this study were 1.3 (interquartile range = 1.1-1.6) and 1.0 (interquartile range = 0.98-1.0), respectively. SAF differences between NCINM and OLINDA/EXM 1.0 were explained by the large inter-phantom anatomical variability. Our results illustrate the importance of realistic human anatomy models for use in dosimetry software. More phantoms and radionuclides, as well as a biokinetic module, will soon be added. Applications of the NCINM program include computation of absorbed doses for use in radiation epidemiologic studies and patient dose monitoring in nuclear medicine.

中文翻译：

---

NCINM：接受核医学手术的患者的器官剂量计算器

核医学是继计算机断层扫描成像之后普通人群的第二大医疗辐射源。关于使用核医学程序的知情决定需要更好地了解辐射剂量的大小和相关的健康风险。然而，现有的基于模型的器官剂量估计工具依赖于简化的人体解剖模型或商业程序。因此，我们基于更复杂的人体解剖模型开发了一种公开可用的剂量计算工具。我们计算了一系列与国际放射防护委员会 (ICRP) 参考数据相匹配的儿科和成人计算人体模型中源和目标区域的多种组合的光子和电子特定吸收分数 (SAF) 的综合库，结合蒙特卡罗辐射传输代码。然后，我们从这些 SAF 和 ICRP 第 107 号出版物中的核衰变数据导出了一个 S 值库。最后，我们创建了一个图形用户界面，名为国家癌症研究所核医学剂量测定系统 (NCINM)，以促进剂量测定过程。大约 1300 万个 S 值来自这项工作中计算的 200 万个 SAF。在剂量测定链的不同步骤进行了综合比较，数据可在 OLINDA/EXM 1.0 和 IDAC 2.1 软件中获得。例如，从 OLINDA/EXM 1.0 和 IDAC 2.1 获得的光子自吸收 SAF 与本研究中计算的那些的中值比率分别为 1.3（四分位距 = 1.1-1.6）和 1.0（四分位距 = 0.98-1.0）。NCINM 和 OLINDA/EXM 1 之间的 SAF 差异。0 是由大的幻影间解剖变异性解释的。我们的结果说明了在剂量测定软件中使用的真实人体解剖模型的重要性。更多的体模和放射性核素，以及一个生物动力学模块，将很快被添加进来。NCINM 程序的应用包括计算用于辐射流行病学研究和核医学患者剂量监测的吸收剂量。