基于患者体质量指数的^(68)Ga-DOTA-NOCPET/CT最佳采集条件

Optimal acquisition protocols of ^(68)Ga-DOTA-NOC PET/CT imaging based on patient's body mass index

目的探讨基于患者体质量指数(BMI)的^(68)Ga-1,4,7,10-四氮杂环十二烷-1,4,7,10-四乙酸-1-柰丙氨酸-奥曲肽(DOTA-NOC)PET/CT最佳采集条件。方法收集89例接受^(68)Ga-DOTA-NOC PET/CT全身扫描的神经内分泌肿瘤患者,根据体质量指数分为偏瘦组(n=13)、正常组(n=40)、超重组(n=31)和肥胖组(n=5)。以真符合计数率、随机符合计数率、等效噪声比(NECR)、随机分数和变异系数(CV)评估PET图像质量,分析其与BMI的关系,并比较4组间差异。结果 89例患者平均BMI为(22.99±3.77)kg/m^2,^(68)Ga-DOTA-NOC注射剂量为(1.04±0.27)MBq/kg体质量。真符合计数率、随机符合计数率和NECR均与显像剂注射剂量呈线性正相关(r=0.71、0.71、0.72,P均<0.01)。NECR在显像剂注射剂量约为1.65MBq/kg体质量时获得最大值。4组真符合计数率差异有统计学意义(F=6.26,P<0.01),且BMI正常组患者真符合计数率与偏瘦组、超重组和肥胖组的比值分别为0.82、1.12和1.28。CV值随显像剂注射剂量的增加而下降(r=0.78,P<0.01),4组间差异有统计学意义(F=16.48,P<0.01)。4组间随机分数差异无统计学意义(F=1.33,P=0.27)。结论基于患者BMI,^(68)Ga-DOTA-NOC PET/CT推荐方案如下:偏瘦患者显像剂注射剂量参考范围为1.05～1.15MBq/kg体质量,最大不超过1.30MBq/kg体质量;超重患者和肥胖患者的每床位采集时间分别延长1.2～1.3倍和1.3～1.5倍。

Objective To explore the optimal acquisition protocols for 68 Ga-DOTA-1-Nal3-octreotide(68 Ga-DOTA-NOC)PET/CT imaging based on patient's body mass index(BMI).Methods Totally 89 patients with neuroendocrine neoplasm(NEN)underwent whole body 68 Ga-DOTA-NOC PET/CT scanning.The patients were classified into 4 groups based on BMI,including underweight group(n=13),normal weight group(n=40),overweight group(n=31)and obese group(n=5).PET image quality was measured with true coincidence rate,random coincidence rate,noise-equivalent counting rate(NECR),random fraction and coefficient of variance(CV)and compared among 4 groups,and their relationship with patient's BMI were analyzed.Results The mean BMI of 89 patients was(22.99±3.77)kg/m 2,and the injection dose was(1.04±0.27)MBq/kg.The true coincidence rate,random coincidence rate and NECR had positive correlation with injection dose(r=0.71,0.71,0.72,all P<0.01).NECR got the maximum value at 1.65 MBq/kg.The true coincidence rate was significantly different among the 4 groups(F=6.26,P<0.01),and the ratio of that for underweight group,overweight group and obese group to normal weight group was approximately 0.82,1.12 and 1.28,respectively.Meanwhile,CV significantly decreased with the increasing of injection dose(r=0.78,P<0.01).There was significant difference of CV among 4 groups(F=16.48,P<0.01).The average random fraction had no significant difference among 4 groups(F=1.33,P=0.27).Conclusion The recommended acquisition protocol for 68 Ga-DOTA-NOC PET/CT imaging based on BMI is as follows:For underweight patients,the injection dose should be approximately 1.05-1.15 MBq/kg,and the maximum injected dose is less than 1.30 MBq/kg,while the optimal acquisition time per bed should be at least 1.2-1.3 times longer in overweight patients and 1.3-1.5 times longer in obese patients.