数字化PET/CT步进式短采集时间的临床应用可行性分析OACSTPCD

Objective:To analyze the effect of short collection time of digital positron emission tomography/computed tomography(PET/CT)on image quality,detected lesion and semi-quantitative parameters,and explore the feasibility of clinical application of short collection time of step by step collection mode.Methods:The digital PET/CT images of 63 subjects were retrospectively analyzed.All of them adopted PET/CT scan to conduct PET/CT examination for whole body according to the collection mode of step by step type and list-mode scan protocol.The reconstruction was implemented according to the different collection time of each bed,and they were divided into 90 s/bed group,60 s/bed group,45 s/bed group and 30 s/bed group.The 90s/bed was used as control group to compare the detection rate of the small lesion of each group("the shorter diameter of smaller radioactive concentration lesion of PET image and the lesion of CT image"was less than 0.5 cm)in PET images,and to measure the objective data of original tumor lesion,and to compare the maximum value(SUVmax),peak value(SUVpeak)and mean value(SUVmean)of standardized uptake value(SUV),noise(SD),metabolic tumor volume(MTV)and total lesion glycolysis(TLG).The signal-noise ratio(SNR),contrast noise ratio(CNR)and target-to-background ratio(TBR)were calculated and compared.The one-way analysis of variance(ANOVA test)was adopted to conduct comparison of inter groups for the image data of 4 groups.The Bland-Altman consistency test was adopted to analyze semi-quantitative parameters of intra group.The Likert 5 scores method was adopted to conduct subject evaluation for the quality of images.The Kappa test was adopted to evaluate the consistency of images.Results:The subjective scores of image quality of 4 groups were all≥3 points,and the consistency of image quality among the four groups was very well(Kappa=0.8,P<0.05).Compared with 90s/bed group,the detection rate of small lesions of other three groups were 100%.The differences of SUVmax,SUVpeak,SUVmean,SD,TLG and MTV of semi-quantitative indicators among 4 groups were not significant(P>0.05).There were significant differences in CNR,SNR and TBR of objective indicators of 18F-FDG PET image quality among 4 groups(F=31.741,34.199,12.021,P<0.001),respectively.There were no significant differences in noise between 60s/bed group and 90s/bed group,and between 45s/bed group and 90s/bed group,respectively.The noise of image of 30s/bed group appeared increase.The Bland-Altman consistent analysis of intra group basically was within 95%confidence interval(CI).Conclusions:The short collection time of step by step mode of digital PET/CT has very good clinical application.