Mazza Anthony, Newhauser Wayne, Pittman Stephen, Halloran Andrew, Maggi Paul, Tran Linh, Gila Brent, Rosenfeld Anatoly, Ziegler James
Medical Physics and Health Physics Program, Department of Physics and Astronomy, Louisiana State University, 439 Nicholson Hall, Tower Dr., Baton Rouge, LA, 70803-4001, USA.
Department of Physics, Mary Bird Perkins Cancer Center, Baton Rouge, LA, USA.
Australas Phys Eng Sci Med. 2017 Sep;40(3):667-673. doi: 10.1007/s13246-017-0576-9. Epub 2017 Sep 8.
This work tested the feasibility of a silicon-on-insulator microdosimeter, which mimics the size and shape of specific cells within the human body, to determine dose equivalent from neutron irradiation. The microdosimeters were analyzed in terms of their basic diode characteristics, i.e., leakage current as a function of bias voltage. Lineal energy spectra were acquired using two different converter layers placed atop the microdosimeter: a tissue-substitute converter made from high-density polyethylene, and a boron converter consisting of epoxy coated with boron powder. The spectra were then converted into absorbed dose and dose equivalent. Experimental results were compared to Monte Carlo simulations of the neutron irradiations, revealing good agreement. Uncertainty in the dose equivalent determinations was 7.5% when using the cell-shaped microdosimeter with the tissue-substitute converter and 13.1% when using the boron converter. This work confirmed that the SOI approach to cell-mimicking microdosimetry is feasible.
本研究测试了一种绝缘体上硅微剂量计的可行性，该微剂量计模仿人体内特定细胞的大小和形状，用于确定中子辐照的剂量当量。根据微剂量计的基本二极管特性，即作为偏置电压函数的漏电流，对其进行了分析。使用放置在微剂量计顶部的两种不同转换层获取线能量谱：一种由高密度聚乙烯制成的组织替代转换层，以及一种由涂有硼粉的环氧树脂组成的硼转换层。然后将这些谱转换为吸收剂量和剂量当量。将实验结果与中子辐照的蒙特卡罗模拟结果进行比较，结果显示吻合良好。使用带有组织替代转换层的细胞形状微剂量计时，剂量当量测定的不确定度为7.5%，使用硼转换层时为13.1%。本研究证实了采用绝缘体上硅方法进行细胞模拟微剂量测定是可行的。
