Karp J S, Daube-Witherspoon M E, Muehllehner G
Department of Radiology, University of Pennsylvania, Philadelphia 19104.
J Cereb Blood Flow Metab. 1991 Mar;11(2):A38-44. doi: 10.1038/jcbfm.1991.35.
Volume imaging positron emission tomographic (PET) scanners with no septa and a large axial acceptance angle offer several advantages over multiring PET scanners. A volume imaging scanner combines high sensitivity with fine axial sampling and spatial resolution. The fine axial sampling minimizes the partial volume effect, which affects the measured concentration of an object. Even if the size of an object is large compared to the slice spacing in a multiring scanner, significant variation in the concentration is measured as a function of the axial position of the object. With a volume imaging scanner, it is necessary to use a three-dimensional reconstruction algorithm in order to avoid variations in the axial resolution as a function of the distance from the center of the scanner. In addition, good energy resolution is needed in order to use a high energy threshold to reduce the coincident scattered radiation.
无隔板且轴向接受角大的容积成像正电子发射断层扫描（PET）扫描仪比多环PET扫描仪具有多个优势。容积成像扫描仪将高灵敏度与精细的轴向采样及空间分辨率相结合。精细的轴向采样可将部分容积效应降至最低，而部分容积效应会影响物体的测量浓度。即使物体尺寸与多环扫描仪中的切片间距相比很大，所测量的浓度仍会随物体轴向位置发生显著变化。对于容积成像扫描仪，有必要使用三维重建算法，以避免轴向分辨率随距扫描仪中心距离的变化而变化。此外，为了使用高能量阈值来减少符合散射辐射，还需要良好的能量分辨率。
