Radiation attenuation by lead and nonlead materials used in radiation shielding garments
Radiation attenuation by lead and nonlead materials used in radiation shielding garments
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DOI：
10.1118/1.2426404
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发表时间：
2007-02-01
期刊：
影响因子：
3.8
通讯作者：
Mainegra-Hing, E.
中科院分区：
文献类型：
--
作者：
McCaffrey, J. P.;Shen, H.;Mainegra-Hing, E.
研究了几种类型的铅基和非铅基辐射屏蔽材料的辐射衰减性能，并与辐射衰减、材料性能、计算光谱和环境剂量当量进行了关联。利用加拿大国家研究委员会良好表征的X射线和伽马射线束，空气动能测量被用来比较各种商业和商业前的辐射屏蔽材料，其平均能量范围从39到205keV。扩展了EGSnrc蒙特卡罗用户代码Cavity.cpp，以提供各种元素的计算光谱，这些元素已被用作辐射屏蔽服中铅的替代品。计算的空气比释动能值与实验值以及通过医学物理和工程研究所提供的SRS-30诊断光谱目录进行了比较。除了服装材料，测量还包括纯铅片，允许直接与常见的行业标准0.25和0.5毫米“铅当量”进行比较。参数“铅当量”具有误导性，因为所有材料(包括铅)的光子衰减特性在能谱上都有很大差异，最大的变化发生在诊断成像范围内。此外，进行空气动能测量通常是为了确定衰减特性，而不参考生物损伤的测量，例如环境剂量当量，其在诊断成像能量范围内也随空气动能显著变化。单一材料或组合不能为所有能量范围提供最佳屏蔽。然而，与传统的铅基材料相比，为特定能量范围选择适当的材料可以显著提高单位质量的屏蔽效果。
The attenuating properties of several types of lead (Pb)-based and non-Pb radiation shielding materials were studied and a correlation was made of radiation attenuation, materials properties, calculated spectra and ambient dose equivalent. Utilizing the well-characterized x-ray and gamma ray beams at the National Research Council of Canada, air kerma measurements were used to compare a variety of commercial and pre-commercial radiation shielding materials over mean energy ranges from 39 to 205 keV. The EGSnrc Monte Carlo user code cavity.cpp was extended to provide computed spectra for a variety of elements that have been used as a replacement for Pb in radiation shielding garments. Computed air kerma values were compared with experimental values and with the SRS-30 catalogue of diagnostic spectra available through the Institute of Physics and Engineering in Medicine Report 78. In addition to garment materials, measurements also included pure Pb sheets, allowing direct comparisons to the common industry standards of 0.25 and 0.5 mm "lead equivalent." The parameter "lead equivalent" is misleading, since photon attenuation properties for all materials (including Pb) vary significantly over the energy spectrum, with the largest variations occurring in the diagnostic imaging range. Furthermore, air kerma measurements are typically made to determine attenuation properties without reference to the measures of biological damage such as ambient dose equivalent, which also vary significantly with air kerma over the diagnostic imaging energy range. A single material or combination cannot provide optimum shielding for all energy ranges. However, appropriate choice of materials for a particular energy range can offer significantly improved shielding per unit mass over traditional Pb-based materials.