Response functions for computing absorbed dose to skeletal tissues from photon irradiation
Response functions for computing absorbed dose to skeletal tissues from photon irradiation
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DOI：
10.1093/rpd/ncm468
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发表时间：
2007-01-01
影响因子：
1
通讯作者：
Petoussi-Henss, N.
中科院分区：
文献类型：
--
作者：
Eckerman, K. F.;Boch, W. E.;Petoussi-Henss, N.
在放射性风险的骨骼组织中的吸收剂量的计算一直是一个困难的问题，因为相关的结构不能表示在传统的几何术语，也不能在用于定义人体的计算模型的断层图像数据中可视化。活性骨髓，白血病诱导中关注的组织，存在于松质骨的松质骨区域内，而有诱发骨癌风险的骨祖细胞被认为是在与矿物表面相邻的软组织内。国际辐射防护委员会（ICRP）建议，分别对诱发白血病和骨癌的海绵体内的活性骨髓和矿物表面10 μ m范围内的软组织的吸收能量取平均值。在其即将提出的建议中，预计后一指南将被修改为包括矿物表面50 μ m范围内的软组织。为了解决计算问题，ICRP参考计算体模的骨架已被细分，以识别与长骨的皮质壳、海绵体和髓腔相关的体素。有人进一步建议，Monte Carlo计算与这些幻影计算的能量沉积在骨骼靶组织的产品的粒子通量在骨骼细分和适用的通量剂量响应函数。本文概述了这种响应函数的光子的发展。
The calculation of absorbed dose in skeletal tissues at radiogenic risk has been a difficult problem because the relevant structures cannot be represented in conventional geometric terms nor can they be visualised in the tomographic image data used to define the computational models of the human body. The active marrow, the tissue of concern in leukaemia induction, is present within the spongiosa regions of trabecular bone, whereas the osteoprogenitor cells at risk for bone cancer induction are considered to be within the soft tissues adjacent to the mineral surfaces. The International Commission on Radiological Protection (ICRP) recommends averaging the absorbed energy over the active marrow within the spongiosa and over the soft tissues within 10 mu m of the mineral surface for leukaemia and bone cancer induction, respectively. In its forthcoming recommendation, it is expected that the latter guidance will be changed to include soft tissues within 50 mu m of the mineral surfaces. To address the computational problems, the skeleton of the proposed ICRP reference computational phantom has been subdivided to identify those voxels associated with cortical shell, spongiosa and the medullary cavity of the long bones. It is further proposed that the Monte Carlo calculations with these phantoms compute the energy deposition in the skeletal target tissues as the product of the particle fluence in the skeletal subdivisions and applicable fluence-to-dose-response functions. This paper outlines the development of such response functions for photons.