A nonlinear spatially variant object-dependent system model for prediction of partial volume effects and scatter in PET
A nonlinear spatially variant object-dependent system model for prediction of partial volume effects and scatter in PET
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DOI：
10.1109/42.700733
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发表时间：
1998-04-01
影响因子：
10.6
通讯作者：
Adler, LP
中科院分区：
文献类型：
--
作者：
Chen, CH;Muzic, RF;Adler, LP
使用正电子发射断层扫描 (PET) 对小病变进行准确定量需要校正部分体积效应。使用 PET 系统高斯模型的传统方法被发现是不够的。开发了一种对非高斯对象相关散射进行建模的新方法。该模型由 8 个简单函数组成，总共 24 个参数。使用圆形和椭圆形圆柱体中的线源和圆盘源的图像以及拟人化的胸部模型来确定参数值。还提出了基于参考对象（21.5 厘米圆柱体）确定各种对象的这些参数值的经验规则。对于七个球体和一个 3.4 厘米的圆柱体，将模型预测的像素值与测量值进行比较。球体中心附近的模型与测量比为 1.03 +/- 0.07，3.4 厘米圆柱体中心附近的模型与测量比为 0.99 +/- 0.03。相比之下，标准单高斯模型的相应比率分别为1.27+/-0.09和1.24+/-0.03，双高斯模型的相应比率为1.13+/-0.09和1.05+/-0.01。我们的模型正确估计了 21.5 厘米圆柱体中线源的散射分数 (28.5%)。由于分散，我们发现直径为 0.6 至 3.4 厘米的球体的活性测量误差比之前预想的更为显着。
Accurate quantitation of small lesions with positron emission tomography (PET) requires correction for the partial volume effect. Traditional methods that use Gaussian models of the PET system were found to be insufficient. A new approach that models the non-Gaussian object-dependent scatter was developed. The model consists of eight simple functions with a total of 24 parameters. Images of line and disk sources in circular and elliptical cylinders, and an anthropomorphic chest phantom were used to determine the parameter values. Empirical rules to determine these parameter values for various objects based on those for a reference object, a 21.5-cm circular cylinder, were also proposed. For seven spheroids and a 3.4-cm cylinder, pixel values predicted by the model were compared with the measured values. The model-to-measurement-ratio was 1.03 +/- 0.07 near the center of the spheroids and 0.99 +/- 0.03 near the center of the 3.4-cm cylinder. In comparison, the standard single Gaussian model had corresponding ratios of 1.27 +/- 0.09 and 1.24 +/- 0.03, respectively, and the corresponding ratios for a double Gaussian model were 1.13 +/- 0.09 and 1.05 +/- 0.01. Scatter fraction (28.5%) for a line source in the 21.5-cm cylinder was correctly estimated by our model. Because of scatter, we found that errors in the measurement of activity in spheroids with diameters from 0.6 to 3.4 cm were more significant than previously appreciated.