ECAT 953B/31 物理特性：新型高分辨率脑正电子断层扫描仪。

Physical characteristics of the ECAT 953B/31: a new high resolution brain positron tomograph.

机构信息

Service Hospitalier Frederic Joliot, CEA, Orsay.

出版信息

IEEE Trans Med Imaging. 1991;10(4):499-504. doi: 10.1109/42.108583.

Abstract

A high spatial resolution brain positron tomograph, the ECAT 953B/31, is presented. The machine consists of two 76.5 cm diameter rings (patient port diameter: 36 cm) made of 24 8x8 BGO detector blocks each, each block being coupled to four 1 in(2) Hammamatsu phototubes. The machine has 15 9 cmx1 mm motorized removable septa, which allows reconstruction of 31 slices 3.375 mm apart. The transaxial resolution (FWHM) in the reconstructed image (with wobbling) is 4.5 mm at center, 5.2 mm (tangential) and 5.6 mm at 10 cm from center. With septa out of the field of view (FOV), the axial resolution degrades to 5.5 mm a center and 6.3 mm at 10 cm from center. At 1 muCi/cc with a 250 keV threshold and a 12 ns coincidence window, the sensitivity is 146100 true events, the ratio of randoms to trues is 0.10, the scatter fraction is 17% and the dead-time losses are 30%. With septa out of the FOV, the sensitivity is increased by a factor 3.6, while the scatter fraction reaches 0.9. Images obtained with (18 )F-DG and H(2)(15)O in human brains and (18 )F-DOPA in a baboon brain demonstrate that the ECAT 953B/31 will be suitable for high resolution and for low count rate brain studies.

摘要

介绍一种高空间分辨率脑正电子断层扫描仪，即 ECAT 953B/31。该仪器由两个直径为 76.5 厘米的圆环（患者端口直径：36 厘米）组成，每个圆环由 24 个 8x8BGO 探测器模块组成，每个模块与四个 1 英寸（2）Hamamatsu 光电倍增管相连。该仪器有 15 个 9 厘米 x1 毫米的可移动电动隔板，可重建 31 个间隔 3.375 毫米的切片。在重建图像（带摆动）中，横向分辨率（FWHM）在中心为 4.5 毫米，在切线方向为 5.2 毫米，在距中心 10 厘米处为 5.6 毫米。当隔板不在视野（FOV）内时，轴向分辨率在中心处降至 5.5 毫米，在距中心 10 厘米处降至 6.3 毫米。在 1 μCi/cc、250keV 阈值和 12ns 符合窗条件下，灵敏度为 146100 个真事件，随机事件与真事件的比例为 0.10，散射分数为 17%，死时间损失为 30%。当隔板不在 FOV 内时，灵敏度提高了 3.6 倍，而散射分数达到 0.9。在人脑（18）F-DG 和 H（2）（15）O 以及狒狒脑中（18）F-DOPA 的图像表明，ECAT 953B/31 将适用于高分辨率和低计数率的脑研究。