摘要
目的 比较多层螺旋CT肺部低剂量与常规剂量检查的X线辐射剂量 ,为低剂量多层螺旋CT普查早期肺癌提供剂量参数。资料与方法 肺部低剂量与常规剂量多层螺旋CT扫描共 5 4例。其中 ,低剂量扫描 2 4例 ,扫描参数为 :12 0kV ,2 0mAs,准直器 4× 5mm ,重建层厚 8mm ,床速 30mm/周 ,螺距为 7,扫描时间 0 .5s/周 ;常规剂量扫描 30例 ,扫描参数为 :12 0kV ,90mAs ,准直器 4× 5mm ,重建层厚 8mm ,床速 30mm/周 ,螺距为 7,扫描时间 0 .5s/周。观察并计算两种扫描剂量的权重CT剂量指数 (CTDIw) ,有效mAs,总mAs ,剂量长度乘积 (DLP)及有效辐射剂量。结果 肺部低剂量扫描的CTDIw为 1.38mGy ,是常规剂量扫描 (6 .2 1mGy)的 2 2 .2 % ;低剂量扫描的DLP为4 4mGy·cm ,明显低于常规剂量扫描的 189mGy·cm(P <0 .0 1) ;低剂量扫描的总mAs为 4 5 9,是常规剂量扫描 (130 8)的 35 .1% ;低剂量扫描的X线最大有效辐射剂量为 0 .9mSv,明显低于常规剂量扫描的 4 .2mSv(P <0 .0 1)。结论 多层螺旋CT肺部低剂量扫描 (2 0mAs)的有效辐射剂量为常规剂量扫描的 2 1.4 % 。
Objective To compare the radiation dose to the chest produced by low-dose multislice helical CT with that produced by conventional dose multislice helical CT.Materials and Methods Fifty-four healthy volunteers were randomly assigned to undergo either low-dose (n=24, 20mAs) or conventional dose (n=30, 90mAs) multislice helical CT scanning with 120kVp, 0.5s, 8mm collimation and pitch 7. The weighted CT dose index (CTDIw), dose-length product (DLP), milliampere seconds (mAs) and radiation dose of two scanning methods were calculated. Results CTDIw for low-dose and conventional dose CT scanning was respectively 1.38 mGy and 6.21 mGy (0.22∶1). DLP of low-dose CT (44 mGy·cm) was markedly lower than that of conventional dose CT scanning (189 mGy·cm) with P<0.01. The total mAs of low-dose CT (459 mAs) was significantly smaller than that of conventional dose CT scanning (1 308 mAs) with P<0.001. The effective dose for low-dose CT scanning was 0.9 mSv, which was lower than that for conventional dose CT scanning (4.2 mSv), with P<0.01.Conclusion The effective dose to chest produced by low-dose multislice helical CT scanning is only 21% of that produced by conventional dose multislice helical CT scanning. Thus, low-dose CT scanning should be used in screening for early lung cancer in high-risk population.
出处
《临床放射学杂志》
CSCD
北大核心
2004年第2期113-115,共3页
Journal of Clinical Radiology
基金
教育部留学回国人员科研基金资助 (编号 :2 0 0 2 -2 4715 )
