Suckling J, Ott R J, Deehan B J
Physics Department, Royal Marsden Hospital, Sutton, Surrey, UK.
Phys Med Biol. 1992 Mar;37(3):751-66. doi: 10.1088/0031-9155/37/3/018.
The major advantage of positron emission tomography (PET) using large area planar detectors over scintillator-based commercial ring systems is the potentially larger (by a factor of two or three) axial field-of-view (FOV). However, to achieve the space invariance of the point spread function necessary for Fourier filtering a polar angle rejection criterion is applied to the data during backprojection resulting in a trade-off between FOV size and sensitivity. A new algorithm due to Defrise and co-workers developed for list-mode data overcomes this problem with a solution involving the division of the image into several subregions. A comparison between the existing backprojection-then-filter algorithm and the new method (with three subregions) has been made using both simulated and real data collected from the MUP-PET positron camera. Signal-to-noise analysis reveals that improvements of up to a factor of 1.4 are possible resulting from an increased data usage of up to a factor of 2.5 depending on the axial extent of the imaged object. Quantitation is also improved.
使用大面积平面探测器的正电子发射断层扫描（PET）相对于基于闪烁体的商用环形系统的主要优势在于其轴向视野（FOV）可能更大（大两到三倍）。然而，为了实现傅里叶滤波所需的点扩散函数的空间不变性，在反投影过程中对数据应用了极角拒绝标准，这导致在视野大小和灵敏度之间进行权衡。Defrise及其同事为列表模式数据开发的一种新算法通过将图像划分为几个子区域的解决方案克服了这个问题。使用从MUP-PET正电子相机收集的模拟数据和真实数据，对现有的先反投影后滤波算法与新方法（具有三个子区域）进行了比较。信噪比分析表明，根据成像对象的轴向范围，数据使用量增加高达2.5倍，可能会使信噪比提高高达1.4倍。定量分析也得到了改善。
