Choi Chansoo, Shin Bangho, Yeom Yeon Soo, Han Haegin, Ha Sangseok, Moon Sungho, Son Gahee, Nguyen Thang Tat, Kim Chan Hyeong, Chung Beom Sun, Bolch Wesley E
Department of Nuclear Engineering, Hanyang University, Seoul, Republic of Korea.
Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States of America.
J Radiol Prot. 2021 Jun 1;41(2). doi: 10.1088/1361-6498/abd88d.
In 2016, the International Commission on Radiological Protection (ICRP) launched Task Group 103 (TG 103) for the explicit purpose of developing a new generation of adult and pediatric reference computational phantoms, named 'mesh-type reference computational phantoms (MRCPs)', that can overcome the limitations of voxel-type reference computational phantoms (VRCPs) of ICRPanddue to their finite voxel resolutions and the nature of voxel geometry. After completing the development of the adult MRCPs, TG 103 has started the development of pediatric MRCPs comprising 10 phantoms (male and female versions of the reference newborn, 1-year-old, 5-year-old, 10-year-old, and 15-year-old). As part of the TG 103 project, within the present study, the skeletal systems, one of the most important and complex organ systems of the body, were developed for each phantom age and sex. The developed skeletal systems, while closely preserving the original bone topology of the pediatric VRCPs, present substantial improvements in the anatomy of complex and/or small bones. In order to investigate the dosimetric impact of the developed skeletons, the average absorbed doses and the specific absorbed fractions for radiosensitive skeletal tissues (i.e. active marrow and bone endosteum) were computed for some selected external and internal exposure cases, which were then compared with those calculated with the skeletons of pediatric VRCPs. The comparison result showed that the dose values of the pediatric MRCPs were generally similar to those of the pediatric VRCPs for highly penetrating radiations (e.g. photons >200 keV); however, for weakly penetrating radiations (e.g. photons ⩽200 keV and electrons), significant differences up to a factor of 140 were observed.
2016年，国际放射防护委员会（ICRP）启动了第103任务组（TG 103），其明确目的是开发新一代成人和儿童参考计算体模，即“网格型参考计算体模（MRCPs）”，以克服ICRP体素型参考计算体模（VRCPs）因有限的体素分辨率和体素几何形状的性质而存在的局限性。在完成成人MRCPs的开发后，TG 103已开始开发包含10种体模（参考新生儿、1岁、5岁、10岁和15岁儿童的男性和女性版本）的儿童MRCPs。作为TG 103项目的一部分，在本研究中，针对每个体模年龄和性别开发了人体最重要和复杂的器官系统之一——骨骼系统。所开发的骨骼系统在紧密保留儿童VRCPs原始骨骼拓扑结构的同时，在复杂和/或小骨骼的解剖结构方面有了显著改进。为了研究所开发骨骼的剂量学影响，针对一些选定的外部和内部照射情况，计算了放射敏感骨骼组织（即活跃骨髓和骨内膜）的平均吸收剂量和比吸收分数，然后将其与用儿童VRCPs骨骼计算得到的结果进行比较。比较结果表明，对于高穿透力辐射（如光子能量>200 keV），儿童MRCPs的剂量值通常与儿童VRCPs的相似；然而，对于低穿透力辐射（如光子能量⩽200 keV的光子和电子），观察到高达140倍的显著差异。
