Imaging Properties of a Positron Tomograph with 280 Bgo Crystals
Imaging Properties of a Positron Tomograph with 280 Bgo Crystals
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DOI：
10.1097/00004728-198112000-00086
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发表时间：
1981-02
影响因子：
1.8
通讯作者：
S. Derenzo;T. Budinger;R. Huesman;J. Cahoon;T. Vuletich
中科院分区：
文献类型：
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作者：
S. Derenzo;T. Budinger;R. Huesman;J. Cahoon;T. Vuletich
本文测量了Donner 280-BGO晶体正电子断层摄影机的基本成象性能，并与装有280 NaI（T1）晶体的同系统作了比较。NaI（T1）晶体为8 mm × 30 mm × 50 mm深，密封在10 mm宽的不锈钢罐中。BGO晶体为9.5 mm宽× 32 mm × 32 mm深，由于它们不吸湿，因此不需要密封罐。在屏蔽间隙为3 cm（截面厚度为1.7 cm FWHM）的情况下，BGO系统的灵敏度为每秒55，000个事件，在20 cm圆柱形水中为每cm 3 1？Ci，这比NaI（T1）系统高2.3倍。200块Ci/cm线源在20 cm直径的水筒中，BGO系统记录到NaI（T1）系统86%的散射分数和66%的偶然分数。BGO的光产额较低，时间分辨率较差，需要比NaI（T1）更宽的符合时间窗口;然而，使用全能量脉冲高度选择的能力，灵敏度提高了2.3倍，导致记录的意外事件的比例总体降低。BGO系统的面内分辨率为9-10 mm FWHM，中心直径为30 cm，NaI（T1）系统的场边缘的径向伸长几乎被消除。
The basic imaging properties of the Donner 280-BGO-Crystal positron tomograph were measured and compared with the same system when it was equipped with 280 NaI(T1) crystals. The NaI(T1) crystals were 8 mm × 30 mm × 50 mm deep, sealed in 10 mm wide stainless steel cans. The BGO crystals are 9.5 mm wide × 32 mm × 32 mm deep and as they are not hygroscopic do not require sealed cans. With a shielding gap of 3 cm (section thickness 1.7 cm FWHM) the sensitivity of the BGO system is 55,000 events per sec for 1 ¿Ci per cm3 in a 20 cm cylinder of water, which is 2.3 times higher than the NaI(T1) system. For a 200 ¿Ci/cm line source on the ring axis in a 20 cm diameter water cylinder, the BGO system records 86% of the scatter fraction and 66% of the accidental fraction of the NaI(T1) system. The lower light yield and poorer time resolution of BGO requires a wider coincidence timing window than NaI(T1); however, the ability to use full-energy pulse height selection with a 2.3-fold improvement in sensitivity results in an overall reduction in the fraction of accidental events recorded. The in-plane resolution of the BGO system is 9-10 mm FWHM within the central 30 cm diameter field, and the radial elongation at the edge of the field in the NaI(T1) system has been nearly eliminated.