拥有“飞行时间”技术的PET/CT性能分析

Research on performances of PET/CT with time-of-flight capability

目的:研究并分析拥有飞行时间(TOF)技术的PET/CT相关性能。方法:参照美国国家电气制造协会(NEMA)NU2-2007标准和厂家测试手册,对PET/CT的能量与时间分辨率、空间分辨率、灵敏度、散射分数、计数特性和图像质量进行性能测试和分析,并对不同型号仪器的性能进行比较,初步探讨飞行时间(TOF)技术对设备性能的影响。结果:系统的能量分辨率和时间分辨率分别为11.59%和499.3ps;空间分辨率在1cm处为4.54mm(横向)和4.85mm(轴向),10cm处为5.13mm(横向径向)、5.55mm(横向切线)和5.76mm(轴向);中心和偏离中心10cm处的灵敏度分别为6.4和6.8(cps/kBq);散射分数为32%;等效噪声计数率(NECR)在14.03kBq/ml时达到峰值为97.6kcps;模体图像中可以清楚分辨直径为10mm的最小热球。结论:拥有飞行时间技术的PET/CT各项性能指标都很优越,尤其在于图像质量的提高,可以缩短采集时间和减少注射药物剂量。

Objective： The performances of a PET/CT scanner with time-of-flight （TOF） capability were measured and studied. Methods： Performances measurements on the scanner were made using the National Electrical Manufactures Association （NEMA） NU2- 2007 procedures and Company＇s Performance Test Manual. The energy/timing resolution, spatial resolution, sensitivity, the scatter fraction, counts performance and imaging quality were measured and analyzed. Different types of PET/CT were compared and the imagingcapabilities of TOF were discussed. Results： The system and 499.3 ps. The transverse and axial resolutions near energy and timing resolution were measured to be 11.59% the center were 4.54mm and 4.85mm, whereas at 10 cm were 5.13 mm, 5.55 mm, 5.76 mm. The absolute sensitivity of this scanner was 6.4（center） and 6.8（10 cm） cps/ kBq, whereas scatter fraction was 32%. The peak NECR was 97.6kcps and occured at 14.03kBq/mL. Image quality measurements with phantom showed that the 10 mm diameter lesion could be clearly distinguished. Conclusion： The PET/CT which achieved TOF capability performed good characteristic, especially in the improvement of image quality. And shorter scan times and lower dose could be gained at the same image quality.