数字X线机常规输出稳定性的测试

Stability measurement of digital X-ray unit on their daily output

目的:通过测试数字成像设备的X线机管电压和曝光时间稳定性,探讨数字成像摄影条件的选择原则。方法:在证明四台数字X线机mAs稳定性合格的前提下,选择合适的kVp档和时间档,测量其高压不准确度和曝光时间不准确度,并同国家标准进行比较。结果:四种X线机管电压不准确度在各个kVp档上均小于5%;时间不准确度大约在20ms档以上小于5%,在20ms档以下大于5%。结论:应用数字X线机摄影时曝光时间不可选择太小。

Objective-To obtain suitable digital radiologic exposure factors of CR and DR by measuring stability of their X-my tube voltage and exposure time. Methods：Four X-ray units were studied, the actual X-ray tube voltage was orderly measured when pre-serdng voltage was 45, 60, 80, 100, 120, the actual exposure time was orderly measured when pre-set exposure time was 2, 6, 40, 50, 100, 500, 1000. By comparing actual measured values and pre-set ones, inaccuracy was obtained. Results：For all of four X-ray units, inaccuracy of voltage were less than 5% ; inaccuracy of exposure time were less than 5% when pre-set time 〉 20ms, and more than 5% when pre-set time 〈 20ms. Conclusion：In practice exposure time should keep high level to ensure X-ray unit output steady.