X-CT设备低对比度分辨力检测方法研究与分析

Study and analysis of the test method of CT low contrast resolution

目的 :检测X CT设备低对比度分辨力 ,评价X CT系统在低对比度条件下区分目标物的能力。方法 :利用Catphan体模的CTP51 5模块进行测试 ,同样扫描条件重复三次 ,得到CT设备在低对比度条件下可分辨目标物的最小直径。结果 :1 %、0 .5 %和 0 .3 %对比度条件下 ,A设备三次重复扫描得到的结果分别为 (2、4和 5mm)、(2、3和 3mm)、(2、3和 5mm) ,螺旋扫描结果为 (2、5和 6mm) ;B设备三次重复扫描得到的结果分别为 (3、5和 7mm)、(2、6和 8mm)、(2、4和6mm)。针对多种对比度检测结果 ,利用Excel绘制低对比度分辨力变化曲线。结论 :利用多种对比度条件评价低对比度分辨力使评价更客观全面。利用低对比度分辨力变化曲线图可对体模不能提供的其他对比度条件下的低对比度分辨力进行估计 。

Objective:To test and evaluate low contrast resolution of CT scanner.Methods:Using the module CTP515 of Catphan phantom,the differentiable minimal diameter (mm) subjects were measured and repeated three times for each test.Results:In Device A,three repeated scan results were (2,4,5mm), (2,3,3mm) and (2,3,5mm) respectively, according to 1%,0.5% and 0.3% contrast scale.Spiral scan result was (2,5,6mm) according to 1%,0.5% and 0.3% contrast scale.In Device B three repeated scan results were (3,5,7mm), (2,6,8mm) and (2,4,6mm).Excel was used to plot low contrast resolution change curves.Conclusion:The evaluation is more impersonal and comprehensive if many contrast scale′s results were used.The low contrast resolution change curve can estimate other contrast scale′s low contrast resolution that can not be provided by the phantom.And this method is very easy.