腰椎64排螺旋CT不同采集模式的剂量研究

64-slice spirl CT scanning dose study in different lumbar acquisition patterns

目的分析比较腰椎64排螺旋CT在三种采集模式设置下的扫描剂量大小,确定腰椎64排螺旋CT的最佳采集模式。方法以水模模拟人体腰椎进行64排螺旋CT扫描,设定3组采集模式:A组(128×0.625)mm、B组(48×0.625)mm、C组(40×0.625)mm。每组采集模式对水模进行40次CT扫描,记录每次扫描的容积剂量指数,计算其剂量长度乘积和有效剂量,使用单因素方差分析进行多个均数比较。结果三组容积剂量指数、剂量长度乘积、有效剂量的比较均为A组(128×0.625 mm)>B组(48×0.625 mm)>C组(40×0.625 mm);C组有效剂量比A和B组平均容积剂量的分别降低17.45%、10.32%。结论腰椎64排MDCT检查时以40×0.625 mm模式进行扫描辐射剂量最小。

Objective Compared the scan doses of the 64 multidetector CT （64-MDCT） in three different lumbar ac-quisition patterns, to determine the optimized one. Methods The water phantom was scanned by the 64-MDCT, and three groups were divided according to acquisition patterns： group A （128 ＆#215;0.625 mm）, group B （48 ＆#215;0.625 mm）, and group C （40＆#215;0.625 mm）. For every group, the water phantom was scanned for 40 times. The volume of CT dose index （CTDIvol）, the DLP and the effective dose were calculated and recorded. One-way ANOVA test was used to compare mean values. Results According to the values of CTDIvol, DLP, and effective dose, the three groups were ordered as follows, group A （128＆#215;0.625mm）〉group B （48＆#215;0.625mm）〉group C （40＆#215;0.625mm）. In group C, the values of effective dose were reduced 17.45%and 10.32%, respectively, in comparison with that in group A and group B. Conclusion The 40＆#215;0.625 mm is the optimized pattern which had minimum radiation dose.