^(18)F-FDG剂量对PET模型图像质量的影响

Effect of^(18)F-FDG dosage alternation on final PET image

目的 探讨不同剂量1 8F 脱氧葡萄糖 (FDG)对PET重建图像质量的影响。方法 将圆柱形模型分别用 2 96、14 8、74、37、18.5、9.2 5和 4 .6 2 5MBq的1 8F FDG水溶液灌注后 ,置探头视野内行PET常规采集 ,然后用临床常规条件重建图像 ,从重建图像中抽取同一层面进行定量分析 :热区标准摄取值 (SUV)测定 ,热区与冷区SUV比值 (ratio) ,本底区标准差 (s)测定 ,采集过程中真实计数与随机计数的比值 (T R)。结果 2 96MBq时 ,图像直观非常不均匀 ,T R =0 .83,其他各项指标无规律。 14 8MBq时 ,图像所见外周放射性分布比较强 ,中间比较弱 ,与未经透射衰减校正的图像相似 ,T R =1 6 4。74、37和 18.5MBq时 ,均匀性、分辨率、对比度都较好 ,本底噪声低 ,各项定量指标都较适中。 9.2 5和4 .6 2 5MBq时 ,本底噪声非常高 ,信息量低 ,严重影响分辨率与均匀性。结论 行1 8F FDGPET显像最佳给药剂量是按体重 4 .6 2 5～ 11.1MBq kg。

Objective To assess PET reconstructed image effected by different 18 F FDG dosages with quantitative and qualitative analysis. Methods To perform PET phantom acquisition by routine clinical parameters after filled with different doses of 18 F FDG solution. An identical slice was extracted from reconstructed image for doing following analysis: the hot area standard uptake value (SUV), the ratio of hot area to cold area, the standard deviation on background area, the ratio of true coincidence to random. Results 296 MBq: The image uniformity was terribly worse, T/R=0.83, other indexes were irregular. 148 MBq: The image presentation looked like the image without attenuation correction, T/R=1.64, other indexes were moderate. 74, 37 and 18.5 MBq: The images were with excellent uniformity, resolution and contrast, the background noise was suitable, all of the quantitative indexes were good. 9.25 and 4.625 MBq: The uniformity and resolution was degraded terribly because of the higher noise and lower information. Conclusion Combining above results with other considerations, such as radiation exposure, information amount and acquisition time, we think the optimal dosage should be 4.625～11.1 MBq/kg.