Clinical research of low-dose protocol for dual-source CT-guided percutaneous pulmonary biopsy
Objective To investigate the application of low X-ray radiation dose scanning for dual-source computed tomography(CT)-guided percutaneous pulmonary biopsy(PPB),and to seek out the optimal protocol to reduce the radiation dose.Methods Seventy patients requiring CT-guided PPB were selected.35 patients underwent dual-source and single-source scanning,while tube current or automatic tube current were applied to them.Five sets of images were obtained for each patient(Group A:100/Sn140 kV,Group B:120 kV,Group C:100 kV,Group D:80 kV,Group E:70 kV).The combination mode of dual-source and different tube currents was adopted in 35 patients,and six sets of images were obtained for each patient(Group F:100/Sn140 kV-automatic tube current,Group G:100/Sn140 kV-fixed tube current,Group H:80/Sn140 kV-automatic tube current,Group I:80/Sn140 kV-Fixed tube current,Group J:140/80 kV-automatic tube current,and Group K:140/80 kV-fixed tube current).Region of interest(ROI)was obtained from infra-spinatus,puncture lesion and lung tissue adjacent to the lesion in each group of images.Signal-to-noise ratio for each ROI and contrast-to-noise ratio between puncture lesions and surrounding lung tissues were calculat-ed,and the image qualityof each group subjectively and objectively evaluated.The CT dose index(CTDI)and dose-length product(DLP)of each group of images were recorded to calculate the effective radiation dose(ED).The image quality and ED of each group were compared.Results The CTDI,DLP and ED of groups A,D and E were lower than group B and group C(P<0.001).There was no statistical difference for CT-value of each ROI in group A～E.The image noise of group D and group E was significantly higher than the other groups(P<0.001),and there was no statistical difference for image noise between group A～C.The signal-to-noise ratio of each ROI and contrast-to-noise ratio of lesion and lung tissue in group D and group E were significantly lower than the other groups(P<0.001).The subjective scores of group D and group E were both lower than the groups A～C,and there was no significant difference in the subjective scores between groups A～C.The CTDI,DLP and ED of group I were lower than the others five groups(P<0.001).There were no sig-nificant differences in all the objective and the subjective indexes of the group F～K images.Conclusion With CT-guided PPB using 80/Sn140 kV and fixed tube current scanning,the image quality can not only meet the requirements of puncture,but also significantly reduce ED,which is suitable for clinical promotion.
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