Miller T R, Wallis J W, Grothe R A
Edward Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri 63110.
J Nucl Med. 1990 Oct;31(10):1732-9.
With modern positron tomographs producing 14, 21, or more transaxial slices, the effects of slice spacing on quantitative reconstruction and three-dimensional displays must be evaluated. This analysis can be approached in terms of the partial volume effect, quantified by the recovery coefficient, or in terms of sampling theory leading to the concept of aliasing. The axial recovery coefficient varies as a function of the position of an object in relation to the slices, with greater variability for larger slice spacings and finer axial resolutions. The aliased image power varies in the same way. The variability in the recovery coefficient and aliasing increase when smaller objects are imaged. Tomographs should be designed with slice spacing approximately half the full-width at half-maximum axial resolution of the tomograph; finer spacing does not appear to confer significant advantages. Thus, quantification and display in positron tomography depend on slice spacing, resolution, and object size.
随着现代正电子断层扫描仪能够生成14、21个或更多的横断面切片，必须评估切片间距对定量重建和三维显示的影响。这种分析可以从由恢复系数量化的部分容积效应的角度进行，也可以从导致混叠概念的采样理论的角度进行。轴向恢复系数随物体相对于切片的位置而变化，切片间距越大且轴向分辨率越高，变化性就越大。混叠图像功率也以相同方式变化。当对较小的物体进行成像时，恢复系数和混叠的变化性会增加。断层扫描仪的设计应使切片间距约为断层扫描仪轴向分辨率半高宽的一半；更精细的间距似乎并没有带来显著优势。因此，正电子断层扫描中的定量分析和显示取决于切片间距、分辨率和物体大小。
