Michigan Univ., Ann Arbor, MI.
IEEE Trans Med Imaging. 1992;11(3):351-60. doi: 10.1109/42.158939.
A method is presented for estimating the Compton-scatter component within the photopeak for local energy spectra measured by an Anger camera in SPECT. Assuming that the measured energy spectrum is the source scatter energy distribution convolved with a known camera energy-resolution function plus an unscattered spectral component, a least-square inverse operation is performed to recover the source scatter distribution. Since this inverse operation is ill-posed, the regularization technique is applied for stabilization. With the method, scatter fractions similar to those from polynomial spectral fitting (PSF) have been observed for experimentally measured, high-count data with a hot (Tc(99m) or I(131)) sphere in a cold cylinder, and the inverse (Tc(99m) only). The method is also less sensitive to the width of the fitting window. A regularization parameter from 1 to 10 is recommended for practical cases. The shape of a recovered source scatter distribution matches that determined by a high-resolution semiconductor-detector measurement as well as by Monte Carlo simulation.
本文提出了一种在 SPECT 中使用 Anger 相机测量局部能谱时估算康普顿散射分量的方法。假设测量的能谱是源散射能分布与已知相机能量分辨率函数卷积加上未散射谱分量的和，通过最小二乘逆运算来恢复源散射分布。由于这种逆运算不适定，因此应用正则化技术进行稳定化。对于实验测量的高计数数据，包括冷圆柱内的热（Tc(99m)或 I(131)）球体和反向（仅 Tc(99m)），用该方法得到的散射分数与多项式谱拟合（PSF）相似。该方法对拟合窗口的宽度也不敏感。对于实际情况，建议使用 1 到 10 之间的正则化参数。恢复的源散射分布的形状与高分辨率半导体探测器测量以及蒙特卡罗模拟确定的形状相匹配。
