迭代重建技术(iDose^4)在肺部低剂量筛查中的应用

Application of low-dose chest CT screening with iterative reconstruction technique(iDose^4)

目的探讨iDose4迭代重建技术在胸部低剂量筛查的方案。方法选取120例胸部体检者,根据不同的体质量指数(BMI)分为A组(BMI≤22)、B组(22<BMI<26)和C组(BMI≥26)。应用Z轴动态管电流调节技术(Z-DOM),预设A组、B组、C组管电流分别为35mAs、45mAs和60mAs,之后利用iDose4平台对各受检者图像分别进行FBP,iDose3、Dose5、iDose7重建。记录3组的CT剂量指数(CTDIvol)、剂量长度乘积(DLP),并估算有效剂量(ED)。结果所获图像质量均可满足诊断要求。A组、B组和C组的CTDIvol均值分别为(0.69±0.08)mGy、(1.09±0.17)mGy和(1.95±0.43)mGy,ED均值分别为(0.33±0.05)mSv、(0.50±0.11)mSv和(0.87±0.23)mSv。结论应用iDose4迭代重建技术,根据受检者的BMI,可获得满意的胸部低剂量CT筛查扫描方案。

Objective To assess the program of low dose chest CT screening with iterative reconstruction technique （iDose4）. Methods Totally 120 subjects who underwent chest CT screening were divided into 3 groups according to body mass index （BMI） ： Group A （BMI≤〈22）, group B （22〈BMI〈26） and group C （BMI≥26）. Z-axial dose modulation （Z- DOM） technique was used to preset tube current of group A, group B and group C as 35 mAs, 45 mAs and 60 mAs, re- spectively. Then the images were reconstructed with standard filtered back projection （FBP）, iDose3, iDose5 and iDoseT, respectively. CT dose index volumes （CTDI_vol） and dose length product （DLP） were recorded, while effective dose （ED） was estimated. The imaging quality was assessed by 2 radiologists. Results The images of each group were acceptable. The average CTDI_vol for group A, B and C was （0.69±0. 08）mGy, （1.09±0.17）mGy and （1.95±0.43）mGy, respective- ly, and the average ED was （0.33±0.05）mSv, （0.50±0.11） mSv and （0.87±0.23） mSv, respectively. Conclusion Application of iDose4 iterative reconstruction technique based on BMI can achieve satisfactory scanning program of chest low-dose screening.