Lee Choonsik, Yeom Yeon Soo, Griffin Keith, Lee Choonik, Lee Ae-Kyoung, Choi Hyung-do
Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Rockville, MD, USA.
Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA.
J Radiat Prot Res. 2020 Jun;45(2):69-75. doi: 10.14407/jrpr.2020.45.2.69. Epub 2020 Jun 30.
Dose conversion coefficients (DCCs) have been commonly used to estimate radiation dose absorbed in human organs from physical measurements of fluence or kerma. The International Commission on Radiological Protection (ICRP) reported a library of DCCs but few studies were conducted on their applicability to non-Caucasian populations. In the present study, we collected a total of eight Korean pediatric and adult voxel phantoms to calculate organ DCCs for idealized external photon irradiation geometries.
We adopted one pediatric female phantom (ETRI Child), two adult female phantoms (KORWOMAN and HDRK Female), and five adult male phantoms (KORMAN, ETRI Man, KTMAN1, KTMAN2, and HDRK Man). A general-purpose Monte Carlo radiation transport code, MCNPX2.7, was employed to calculate dose conversion coefficients for 13 major radiosensitive organs in six irradiation geometries (antero-posterior, postero-anterior, right lateral, left lateral, rotational, and isotropic) and 33 photon energy bins (0.01 - 20 MeV).
The DCCs for major radiosensitive organs (e.g., lungs and colon) in AP geometry reasonably agreed across the eight Korean phantoms whereas those for deep-seated organs (e.g., gonads) significantly varied. DCCs of the child phantom were overall greater than those of the adult phantoms. Comparison with the ICRP Publication 116 data showed reasonable agreements with Korean phantom-based data. The variations in organ DCCs were well explained using the distribution of organ depths from the phantom surface.
A library of dose conversion coefficients for major radiosensitive organs in a series of pediatric and adult Korean voxel phantoms was established and compared with the reference data from ICRP. Comparison with the data from the ICRP reference adult voxel phantoms showed that our Korean phantom-based data is overall in a reasonable agreement with the ICRP reference data.
剂量转换系数（DCCs）通常用于根据注量或比释动能的物理测量值估算人体器官吸收的辐射剂量。国际放射防护委员会（ICRP）报告了一个剂量转换系数库，但针对其在非白种人群中的适用性开展的研究较少。在本研究中，我们总共收集了八个韩国儿童和成人体素模型，以计算理想化外部光子照射几何条件下的器官剂量转换系数。
我们采用了一个儿童女性模型（ETRI儿童模型）、两个成人女性模型（韩国女性模型和HDRK女性模型）以及五个成人男性模型（韩国男性模型、ETRI男性模型、KTMAN1、KTMAN2和HDRK男性模型）。使用通用蒙特卡罗辐射传输代码MCNPX2.7，计算六种照射几何条件（前后位、后前位、右侧位、左侧位、旋转位和各向同性）和33个光子能量区间（0.01 - 20 MeV）下13个主要辐射敏感器官的剂量转换系数。
在前后位几何条件下，八个韩国模型中主要辐射敏感器官（如肺和结肠）的剂量转换系数合理一致，而深部器官（如性腺）的剂量转换系数差异显著。儿童模型的剂量转换系数总体上大于成人模型。与ICRP第116号出版物数据的比较表明，与基于韩国模型的数据合理一致。利用模型表面器官深度分布很好地解释了器官剂量转换系数的差异。
建立了一系列韩国儿童和成人体素模型中主要辐射敏感器官的剂量转换系数库，并与ICRP的参考数据进行了比较。与ICRP参考成人体素模型的数据比较表明，我们基于韩国模型的数据总体上与ICRP参考数据合理一致。
