数字化X射线摄影系统质量控制检测研究

Research of test for quality control of medical DR system

目的:对数字化X射线成像系统的能量发生装置、X射线机曝光参数和影像采集装置的DR影像性能进行检测验收,研究DR的质量控制检测步骤与测算方法。方法:采用Piranha型X射线机多功能质量检测仪与PTW NORMI13型性能体模对DR进行千伏、曝光时间、半价层、空间分辨力、低对比度分辨力和可见灰度级等参数进行检测,检测完毕根据测算方法计算出检测结果。结果:(1)管电压准确性相对偏差为0.517%,重复性变异系数为0.134%;(2)曝光时间准确性相对偏差≥100 ms时为0.640%、<100 ms时为0.633%;(3)辐射输出重复性变异系数为0.292%,半价层为3.02 mm Al(80 k V),空间分辨力为3.4 lp/mm,低对比度分辨力为1.0%,可见灰度级为7个。根据国家卫生行业标准WS76-2017与WS521-2017该DR检测验收获得通过。结论:通过对DR的质量控制检测,可以客观的反映设备能量发生装置和影像采集装置的性能,从而保证设备处于良好的运行状态。

Objective： To detect the specifications of digital radiography （DR） so as to research the test procedure and calculation method of quality control for DR in routine work. Methods： The Piranha X–ray multifunctional detector and PTW NORMI 13 performance phantom were used to test the technical parameters of kV, exposure time, half value layer, spatial resolution, low contrast resolution and visible gray scale and so on. The results were calculated according to the formula. Results： The results indicated that the relative deviation of tube voltage accuracy was 0.517%, and coefficient of variation was 0.134%. And the relative deviation of exposure time accuracy was 0.640% when time ≥100 ms, and it was 0.633% when time less than 100ms. Besides, CV of radiation output was 0.2923%, and the half-value layer, the spatial resolution, the low contrast resolution and visible gray level were 3.02 mmAl （80 kV）, 3.4 lp/mm, 1.0% and 7, respectively. The test of check and acceptation of DR was qualified according to the requirement of the People＇s Republic of China health care industry standards （WS 76-2017 and WS 521-2017）. Conclusion： Through the test for quality control of DR, the performances of device of producing power and device of image-acquisition can were objectively reflected, and thus the better operative situation of the device can be ensured based on above results.