Division of Imaging Diagnostics and Software Reliability, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, Food and Drug Administration, 10903 New Hampshire Ave, Silver Spring, MD, 20993, USA.
Medical Systems Research & Development Center, R&D Management Headquarters, FUJIFILM Corp, 798, Miyanodai, Kaisei-machi, Ashigarakami-gun, Kanagawa, 258-8538, Japan.
Med Phys. 2017 Aug;44(8):4035-4039. doi: 10.1002/mp.12389. Epub 2017 Jul 6.
This work studies the detective quantum efficiency (DQE) of a-Se-based solid state x-ray detectors for medical imaging applications using ARTEMIS, a Monte Carlo simulation tool for modeling x-ray photon, electron and charged carrier transport in semiconductors with the presence of applied electric field.
ARTEMIS is used to model the signal formation process in a-Se. The simulation model includes x-ray photon and high-energy electron interactions, and detailed electron-hole pair transport with applied detector bias taking into account drift, diffusion, Coulomb interactions, recombination and trapping. For experimental validation, the DQE performance of prototype a-Se detectors is measured following IEC Testing Standard 62220-1-3.
Comparison of simulated and experimental DQE results show reasonable agreement for RQA beam qualities. Experimental validation demonstrated within 5% percentage difference between simulation and experimental DQE results for spatial frequency above 0.25 cycles/mm using uniform applied electric field for RQA beam qualities (RQA5, RQA7 and RQA9). Results include two different prototype detectors with thicknesses of 240 μm and 1 mm.
ARTEMIS can be used to model the DQE of a-Se detectors as a function of x-ray energy, detector thickness, and spatial frequency. The ARTEMIS model can be used to improve understanding of the physics of x-ray interactions in a-Se and in optimization studies for the development of novel medical imaging applications.
本工作使用 ARTEMIS（一种用于建模半导体中 X 射线光子、电子和带电载流子输运的蒙特卡罗模拟工具，同时考虑了外加电场的影响），研究了用于医学成像应用的基于 a-Se 的固态 X 射线探测器的量子探测效率（DQE）。
ARTEMIS 用于模拟 a-Se 中的信号形成过程。该仿真模型包括 X 射线光子和高能电子相互作用，以及详细的电子-空穴对输运，考虑了外加探测器偏置的漂移、扩散、库仑相互作用、复合和俘获。为了进行实验验证，根据 IEC 测试标准 62220-1-3 测量了原型 a-Se 探测器的 DQE 性能。
模拟和实验 DQE 结果的比较表明，对于 RQA 束质，两者具有合理的一致性。实验验证表明，对于 RQA5、RQA7 和 RQA9 束质，在空间频率高于 0.25 周期/mm 时，使用均匀外加电场，模拟和实验 DQE 结果之间的差异在 5%以内。结果包括两种不同厚度的 240μm 和 1mm 原型探测器。
ARTEMIS 可用于模拟 a-Se 探测器的 DQE 作为 X 射线能量、探测器厚度和空间频率的函数。ARTEMIS 模型可用于深入了解 a-Se 中 X 射线相互作用的物理特性，并优化用于开发新型医学成像应用的研究。
