Optimizing non-Pb radiation shielding materials using bilayers
Optimizing non-Pb radiation shielding materials using bilayers
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DOI：
10.1118/1.3260839
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发表时间：
2009-12-01
期刊：
影响因子：
3.8
通讯作者：
Shen, H.
中科院分区：
文献类型：
--
作者：
McCaffrey, J. P.;Mainegra-Hing, E.;Shen, H.
目的：本研究的目的是通过将非铅辐射屏蔽材料构造成由不同金属粉末包埋的弹性体层组成的双层结构，从而使其重量最小化。方法：通过测量和蒙特卡罗(MC)计算，研究了几种非铅金属双层膜在30-150keV的X射线能量范围内的衰减特性。金属层的选择是基于低成本、无毒和互补的光电吸收特性。使用EGSnrc用户程序Cavity.cpp计算由这些金属层衰减后所产生的x射线通量谱。空气比释动能衰减是使用商业制造的金属/弹性体测试层测量的。这些层是在加拿大渥太华的国家测量标准研究所使用初级标准校准光束进行照射的，利用德国标准DIN 6857中推荐的六种X射线光束质量。测量和计算都是为了接近表面辐射和软组织10毫米深度的穿透辐射。表面辐照测量探测器的MC模型点和位置都直接对着衰减材料的下游表面，如DIN 6857所建议的那样。结果：金属双层膜的上游低Z和下游高Z的顺序提供的衰减明显大于相反的顺序。结论：根据X射线质量的不同，适当选择两个互补的金属包埋弹性体层，可使辐射屏蔽服的重量比铅基弹性体服装减轻25%，同时提供同等的衰减。(C)2009年美国医学物理学家协会。[DOI：10.1118/1.3260839]
Purpose: The objective of this study was to demonstrate that the weight of non-Pb radiation shielding materials can be minimized by structuring the material as a bilayer composed of different metal-powder-embedded elastomer layers.Methods: Measurements and Monte Carlo (MC) calculations were performed to study the attenuation properties of several non-Pb metal bilayers over the x-ray energy range 30-150 keV. Metals for the layers were chosen on the basis of low cost, nontoxicity, and complementary photoelectric absorption characteristics. The EGSnrc user code cavity.cpp was used to calculate the resultant x-ray fluence spectra after attenuation by these metal layers. Air kerma attenuation was measured using commercially manufactured metal/elastomer test layers. These layers were irradiated using the primary standard calibration beams at the Institute for National Measurement Standards in Ottawa, Canada utilizing the six x-ray beam qualities recommended in the German Standard DIN 6857. Both the measurements and the calculations were designed to approximate surface irradiation as well as penetrating radiation at 10 mm depth in soft tissue. The MC modeling point and the position of the measurement detector for surface irradiation were both directly against the downstream face of the attenuating material, as recommended in DIN 6857.Results: The low-Z upstream/high-Z downstream ordering of the metal bilayers provided substantially more attenuation than the reverse order. Optimal percentages of each metal in each bilayer were determined for each x-ray radiation beam quality.Conclusions: Depending on the x-ray quality, appropriate choices of two complementary metal-embedded elastomer layers can decrease the weight of radiation shielding garments by up to 25% compared to Pb-based elastomer garments while providing equivalent attenuation. (C) 2009 American Association of Physicists in Medicine. [DOI: 10.1118/1.3260839]