非晶硒平板探测器DR与CR模拟病变描述和剂量降低的对比研究

目的 比较非晶硒平板探测器DR与CR对模拟肺部病变的描述,并对剂量降低情况进行评价。方法 模拟线状、网状和结节病变结构置入仿真胸部体模内,应用DR和CR分别对不同mAs设置的体模曝光,记录体模的入射体表剂量。收集不同剂量的硬拷贝照片,由4位放射医师随机地实施模拟肺部病变显示度评价。采用秩和(Wilcoxon)检验进行统计学分析。结果 用2.0、3.2 mAs曝光时,DR与CR对模拟线状、网状病变的显示度差异有统计学意义(模拟线状病变:Z=-2.032,P=0.042;Z=-2.375, P=0.018。模拟网状病变: Z=-2.680, P=0.007;Z=-2.670, P=0.008)。用5.0、6.3 mAs曝光时,两者对模拟线状、网状病变的显示度差异无统计学意义(P＞0.05)。2.0、3.2、5.0、6.3 mAs曝光档,对于小结节(直径小于10 mm)的检测DR均优于CR(Z=-2.237, P=0.018; Z=-2.384, P=0.017; Z=-2.388, P=0.017; Z=-2.366, P=0.018)。当3种模拟肺部病变都显示清楚时,用非晶硒DR系统的入射体表剂量降低约65%。结论 对微小低对比病变的描述,非晶硒平板探测器DR优于CR且明显地降低曝光剂量。

Amorphous selenium flat-panel detector digital radiography versus computed radiography:phantom study of depiction of simulated lesion and dose reduction

Objective To compare an amorphous selenium fiat-panel detector digital radiography(DR) with a computed radiography(CR) for the depiction of simulated pulmonary lesion,as well as for evaluation of dose reduction.Methods Simulated linear,reticular,and nodular lesion were located in all anthropomorphic chest phantom.The phantom was exposed by DR and CR with different mAs sets.The entrance surface doses were recorded for all images.Hard copy images were generated at different dose levels.Images were presented in a random order to four independent radiologists.They subjectively rated the visibility of simulated pulmonary lesion. Statistical significance of difference was analvsed with wilcoxon test.Resuits The visibility of simulated linear and reticular lesions on the images obtained with DR was superior to the images from CR at 2.0 and 3.2 mAs.P <0.05(Simulated linear lesion:Z=-2.032,P=0.042;Z=-2.375,P=0.018.Simulated reticular lesion:Z=-2.680,P=0.007;Z=-2.670,P=0.008).However,there wag no statistically significant difference between DR and CR at 5.0 and 6.3 mAs(P>0.05).DR was superior to CR in detection sinail nodular(diameter<10 mm)lesions at different dose level(mAs:2.0,3.2,5.0,6.3),P<0.05(Z=-2.237, P=0.018;Z=-2.384,P=0.017;Z=-2.388,P=0.017;Z=-2.366,P=0.018).When the visibility of simulated pulmonary lesion for DR and CR were equal,The radiation dose was reduce approximately 65% with the DR.Conclusious DR was superior to CR in depiction of tiny lesion and dose reduction greatly.