自贡市X射线CT机质量控制检测与放射防护监测结果分析

目的 通过对自贡市全部26台X射线CT机进行质量控制检测与其机房进行放射防护监测，了解CT机设备性能现状和机房放射防护情况，以便研究提高CT机设备性能和机房防护效果的措施。方法 按照《X射线计算机断层摄影装置质量保证检测规范》GB 17589-2011、《医用X射线诊断放射防护要求》GBZ 130-2013、《X射线计算机断层摄影放射卫生防护标准》GBZ 165-2012提出的方法和要求进行检测与评价。结果 自贡市26台X射线CT机质量控制指标中CTDI_w、高对比分辨力、低对比可探测能力、CT值（水）、噪声、重建层厚偏差、诊断床定位精度、定位光精度的合格率为100%，均匀性的合格率为96.2%，CT值线性的合格率为92.3%，有23台CT机的质量控制检测指标全部合格，总合格率为88.5%。26个CT机房中有1个机房的周围剂量当量率超过2.5 μSv·h^-1，合格率为96.2%。结论 CT机质量控制检测项目中诊断床定位精度、定位光精度、重建层厚偏、CTDI_w（mGy）、CT值（水）、噪声、高对比分辨力、低对比可探测能力的合格率高，但均匀性和线性的合格率稍低，CT机房放射防护监测中仍有不合格监测点，因此须进一步加强质量控制与放射防护工作。

Analysis of X-ray CT quality control testing and radiation protection monitoring in Zigong City

Objective To understand the performance of the X-ray CT scanners and the protection effect of the CT rooms in Zigong City, quality control testing of all 26 X-ray CT scanners and radiation protection detection of all 26 CT rooms were conducted, so as to study the measures to improve the performance of CT equipment and the protection effect of the CT room.Methods According to the methods and requirements proposed by the quality assurance test specification of X-ray computed tomography equipment (GB 17589-2011), the requirements of radiological protection for medical X-ray diagnosis (GBZ 130-2013), and the standards of radiological health protection for X-ray computed tomography (GBZ 165-2012), quality control testing and evaluation was conducted.Results The qualified rates of weighted CT dose index, high-contrast resolution, low contrast detectability, CT value (water), noise, accuracy of locating light, deviation of reconstructed slice thickness and positional accuracy of diagnostic couch were all reached to 100%. The qualified rate of uniformity of CT number was 96.2%, and the qualified rate of linearity of CT number was 92.3%. The quality control test indicators of 23 CT machines are all qualified, with a total pass rate of 88.5%. The peripheral dose equivalent rate of only 1 CT room in the 26 CT rooms exceeds 2.5 μSv/h, and the pass rate was 96.2%.Conclusion The qualified rates of weighted CT dose index, high-contrast resolution, low contrast detectability, CT number of water, noise, accuracy of locating light, deviation of reconstructed slice thickness and positional accuracy of diagnostic couch were high, but the qualified rate of uniformity and linearity of CT number were relatively low. There were still unqualified monitoring points in radiological protection monitoring for CT rooms. Therefore, quality control and radiological protection should be further strengthened.