32模块quadHIDAC小动物PET扫描仪的性能评估。

Performance evaluation of the 32-module quadHIDAC small-animal PET scanner.

作者信息

Schäfers Klaus P, Reader Andrew J, Kriens Michael, Knoess Christof, Schober Otmar, Schäfers Michael

机构信息

Department of Nuclear Medicine, University Hospital of Muenster, Albert-Schweitzer-Strasse 33, 48129 Muenster, Germany.

出版信息

J Nucl Med. 2005 Jun;46(6):996-1004.

PMID:15937311

Abstract

UNLABELLED

The 32-module quadHIDAC is a commercial, high-resolution animal PET scanner, based on gas multiwire proportional chambers.

METHODS

Several scanner parameters that characterize the performance of the system were evaluated in this study, such as spatial resolution, absolute sensitivity, scatter, and count rate performance. The spatial resolution has been determined with filtered back-projected images of a point source. A line source, a mouse phantom, and a rat phantom have been used to characterize the count rate performance. The scatter fraction and photon absorption have been measured with a mouse scatter phantom. The absolute sensitivity has been determined using a line source with aluminum shields of different thickness.

RESULTS

Spatial resolution (full width at half maximum) offers values of 1.08, 1.08, and 1.04 mm in the radial, tangential, and axial directions, respectively. The maximum count rate is 370 kcps for a line source of 19 MBq activity. Registration of scattered coincidences is caused primarily by photons scattering in the large coincidence detectors. For a mouse-sized object, only 5% of the measured coincidences scatter inside the animal, whereas 32% of the coincidences scatter inside the detectors. Photon attenuation within a mouse phantom was 22%. After scatter corrections, the absolute sensitivity of the system is 15.2 cps/kBq for a point source and 13.7 cps/kBq for a 7.8-cm-long line source. The peak noise equivalent count rates are 67 kcps@209 kBq/mL for the mouse phantom and 52 kcps@96 kBq/mL for the rat phantom. Finally, a comparison has been made with the microPET R4, a commercial scintillation crystal-based PET camera.

CONCLUSION

The results confirm that the quadHIDAC PET scanner, with its large cylindric field of view (165-mm diameter, 280-mm axial length), is particularly suitable for imaging small animals such as mice or rats.

摘要

未标注

32 模块 quadHIDAC 是一款基于气体多丝正比室的商用高分辨率动物正电子发射断层扫描仪。

方法

本研究评估了表征该系统性能的几个扫描仪参数，如空间分辨率、绝对灵敏度、散射和计数率性能。空间分辨率通过点源的滤波反投影图像确定。使用线源、小鼠模型和大鼠模型来表征计数率性能。使用小鼠散射模型测量散射分数和光子吸收。使用带有不同厚度铝屏蔽的线源确定绝对灵敏度。

结果

空间分辨率（半高宽）在径向、切向和轴向上分别为 1.08、1.08 和 1.04 毫米。对于活度为 19 MBq 的线源，最大计数率为 370 kcps。散射符合事件的记录主要是由光子在大型符合探测器中散射引起的。对于小鼠大小的物体，仅 5% 的测量符合事件在动物体内散射，而 32% 的符合事件在探测器内散射。小鼠模型内的光子衰减为 22%。经过散射校正后，系统对于点源的绝对灵敏度为 15.2 cps/kBq，对于 7.8 厘米长线源为 13.7 cps/kBq。小鼠模型的峰值噪声等效计数率为 67 kcps@209 kBq/mL，大鼠模型为 52 kcps@96 kBq/mL。最后，与 microPET R4（一款基于闪烁晶体的商用正电子发射断层相机）进行了比较。