Dept. of Electr. Eng., Laval Univ., Que.
IEEE Trans Med Imaging. 1992;11(3):379-85. doi: 10.1109/42.158942.
The point spread function (PSF) of a ring PET tomograph is known to be spatially variant and difficult to obtain because it must be reconstructed from projections. A mathematical model was developed to simulate the data acquisition from a point source and to reconstruct the PSF, taking into account weighting functions to describe the detector response functions. In order to investigate the effect of the detector weighting function on the PSF, the reconstruction, based on the filtered backprojection algorithm, was implemented with three classes of weighting functions of decreasing complexity: exact, locally invariant, and constant. Significant differences are observed to result from the three hypotheses, and this is shown to lead to distorted PSFs and to erroneous estimates of the intrinsic resolution off the center of the tomograph.
环 PET 断层扫描仪的点扩散函数 (PSF) 是空间变化的，难以获取，因为它必须从投影重建。本文开发了一个数学模型来模拟点源的数据采集，并进行 PSF 重建，同时考虑了加权函数来描述探测器的响应函数。为了研究探测器加权函数对 PSF 的影响，基于滤波反投影算法的重建使用了三类简化的加权函数：精确的、局部不变的和常数的。从三个假设中观察到明显的差异，这导致 PSF 扭曲，并导致在断层扫描仪中心之外的固有分辨率的错误估计。
