Biomed. Eng. Dept., Worcester Polytech. Inst., MA.
IEEE Trans Med Imaging. 1990;9(4):430-8. doi: 10.1109/42.61758.
The geometric component of the point spread function (PSF) of a gamma camera collimator can be determined analytically, and the penetration component can be calculated readily by numerical ray-tracing. A Monte Carlo simulation of photon transport which includes collimator scatter is developed. The simulation was implemented with an array processor which propagates up to 1024 photons in parallel, allowing accurate estimates of the total radial PSF in less than a day. The simulation was tested by imaging monoenergetic point sources of Tc-99m, Cr-51, and Sr-85 (140, 320, and 514 keV, respectively) on a General Electric Star Cam with low-energy, general-purpose, and medium-energy collimators. Comparisons of measured and simulated PSFs demonstrate the validity of the model and the significance of collimator scatter in the degradation of image quality.
伽马相机准直器的点扩散函数（PSF）的几何分量可以进行分析确定，而穿透分量可以通过数值光线追踪轻松计算。开发了一种包括准直器散射的光子传输的蒙特卡罗模拟。该模拟使用可以并行传播多达 1024 个光子的阵列处理器来实现，从而在不到一天的时间内即可准确估计总径向 PSF。通过使用低能、通用和中能准直器在通用电气 Star Cam 上对 Tc-99m、Cr-51 和 Sr-85（分别为 140、320 和 514keV）单能点源进行成像，对模拟进行了测试。测量和模拟 PSF 的比较证明了该模型的有效性以及准直器散射对图像质量退化的重要性。
