CT图像均匀性数据的质量管理

Quality Control in Uniformity of CT Image Data

目的将统计学方法及统计过程控制,应用于CT图像均匀性数据的质量管理中,以提高CT图像质量,更好地为肿瘤放疗患者提供更加清晰的图像。方法根据JJG 1026-2007国家计量检定规程中对CT均匀性检测方法及标准,检测我院肿瘤放疗模拟定位CT机的均匀性,并利用统计过程的控制策略处理检测数据并绘制控制图。结果根据控制图得出,我院肿瘤放疗模拟定位CT机在刚开机预热后至运行到需要散热的过程中符合正态分布曲线,CT图像均匀。在同一k V值下m A值在200 m A左右时CT图像均匀性较为稳定;在同一m A值下,k V值在130 k V时CT图像的均匀性较为稳定。结论建议我院肿瘤放疗科的CT模拟定位机的操作技师在开机预热后可以空机运行1次;尽可能选择机器运行参数在200 m A、130 k V左右,使CT图像的均匀性保持在一个很好的状态中;保持CT机房合适的环境温度。

Objective To apply statistical method and statistical process control to quality management on uniformity of CT image data, which was aimed at improving the quality of CT images and better providing more clear CT images for patients of tumor radiotherapy (RT). Methods The uniformity of simulating location CT device for tumor RT in our hospital was detected, and the adopted detectionmethod was referred to verification method for uniformity of CT images, which was described in Verification Regulation of Medical Diagnostic X-ray Radiation Source for Spiral CT (JJG 1026-2007 ofNational Metrology Verification Regulation of PRC). Then the data gained from detection above weretested and disposed through the control strategy of statistical process so as to implement a control chartdrawing. Results The control chart showed that uniformity of CT image data, which were obtainedon the operating machine from the time after warm-up to the time before heat dissipation, accordedwith normal distribution curve. Besides, under the fixed tube voltage (same kV value), uniformity ofCT images was relatively stable when tube current was about 200 mA. In the other hand, uniformity ofCT images was relatively stable if tube voltage was around 130 kV in view of the same tube current.Conclusion The technician, who operated simulating location CT device for tumor RT in our hospital,was advised firstly to do no-load operation once after the warm-up, secondly to maintain operation parameters of CT device at 200 mA, 130 kV more or less, keeping the CT image uniformity at a good state. In addition, the ambient temperature in CT device room should be set suitable.