【摘要】 目的 探讨基于原始数据的迭代重建(SAFIRE)技术结合低剂量在胸部平扫中的最佳扫描方案。方法 选择健康成年家犬11只，固定管电流为65 mA,分别行120 kV、100 kV、80 kV、70 kV扫描；固定管电压100 kV条件下，管电流减半剂量(32 mA)扫描。将所得数据分别采用传统滤波反投影法(FBP)和SAFIRE(强度3级)重建得到10组图像。以常规剂量120 kV/65 mA结合FBP重建作为对照组，其余为实验组。比较不同扫描条件下CT剂量指数(CTDIvol)、剂量长度乘积(DLP)、有效剂量(ED)及10组重建图像平均CT值、噪声、信号噪声比(SNR)、对比噪声比(CNR)及图像质量评分等。结果 10组图像中除脂肪组织CT值差异有统计学意义(P<0.05)外，肺组织、上腔静脉、主动脉弓、脊柱旁肌肉CT值差异均无统计学意义(P>0.05)。与对照组(120 kV/65 mAFBP)比较，100 kV/65 mASAFIRE组噪声减低、SNR及CNR升高、图像质量评分略高，辐射剂量减少了40.00%;80 kV/65 mA和100 kV/32 mA组辐射剂量分别减少了71.33%和70.00%,图像质量略降低但绝对评分均>4分，且100 kV/32 mA组评分稍高于80 kV/65 mA组；70 kV/65 mA组图像质量减低但达到诊断要求(>3分),辐射剂量可减少81.33%。结论 胸部平扫结合SAFIRE重建，100 kV/65 mA图像质量相当于常规扫描重建图像；70 kV/65 mA图像既能满足诊断要求又能明显降低辐射剂量。更多还原

【Abstract】 Objective To explore the optimized scanning parameters of low-dose un-enhanced chest CT with sinogram affirmed iterative reconstruction(SAFIRE).Methods Eleven healthy adult domestic dogs underwent chest scanning of 120 kV,100 kV,80 kV,70 kV with a fixed tube current of 65 mA and halved tube current of 32 mA with a fixed tube voltage of 100 kV.The data were reconstructed with filtered back projection(FBP) and SAFIRE(strength grade 3) respectively to obtain ten groups of images.The regular dose(120 kV/65 mA)combining with FBP reconstruction was as normal control group,and other groups as experimental groups.CT dose index(CTDI),dose length product(DLP),and effective dose(ED) at different dose were compared,and average CT value,noise,signal-to-noise ratio(SNR),contrast-to-noise ratio(CNR) and image quality score of ten groups of images were comparatively analyzed.Results No significant differences were found in average CT value for lung tissue,the superior vena cava,the aortic arch,and spinal muscles among ten groups(P>0.05),except adipose tissue(P<0.05).Compared to the control gro up,radiation dose of the 100 kV/65 mA-SAFIRE group decreased by 40.00%,noise of this group reduced,SNR and CNR increased,image quality score was slightly higher.Radiation dose of 80 kV/65 mA and 100 kV/32 mA groups,compared to the control group,decreased by 71.33% and 70.00% respectively;image quality was slightly degraded but the subjective image quality scores were above 4,which on the latter group was slightly higher than that on the former.Image quality of 70 kV/65 mA group was reduced but could meet the requirements of diagnosis(image quality score>3),and the radiation dose of this group decreased by 81.33%.Conclusion Reconstructed with SAFRIE technology,the image quality of 100 kV/65 mA scanning of chest CT is similar to that of routinely reconstructed images in regular dose,while the image quality of 70 kV/65 mA scanning can not only meet the requirements of diagnosis but also obviously reduce radiation dose.更多还原