CT机应用质量检测与临床照片图像质量关系

Relationship between CT scanner quality testing and image quality

目的 :分析CT设备应用质量检测结果与临床照片图像质量之间的关系 ,探讨检测方法的改进措施。方法 :采用Catphan 5 0 0体模和标准剂量组合头模 ,依照军队CT机应用质量检测与评审规范 ,对 118台CT设备实施检测 ;同时随机抽取近期人体各部位临床照片共七张 ,由专家组评审分级。以图像质量等级为关键字 ,对各参数进行归类统计。结果 :临床照片图像质量与剂量指数、噪声水平、密度分辨率和空间分辨率关系密切。结论 :实际检测中 ,要根据参数之间的相互关系合理安排先后顺序 :先测量层厚 ,并校准直至合格 ;然后进行照射剂量水平的控制 ;再继续其它参数的检测。

Objective:To improve the testing methods by studying the relationship between CT sanner quality testing and image quality.Methods:118 CT scanners were tested by a set of Catphan 500 phantom and a set of standard dose meter. 7 random images associated with different parts of the whole body were evaluated and graded by clinical experts. Then, statistics of the testing results were made corresponding to image quality grade.Results:The qualities of clinical images were closely related to such parameters as CTDI, noise level, density resolution and spatial resolution. Conclusion:It is important in the QA testing to reasonablly arrange the order of parameters: slice thickness and its calibration first,followed by CTDI and other parameters.