数字乳腺摄影系统的质量控制检测与评价

Quality control testing and evaluation for digital mammography

目的对3套数字乳腺摄影系统进行质量控制检测与评价。方法应用欧洲乳腺癌普查和诊断质量控制导则中推荐的方法，结合国内乳腺摄影评价标准，对3套数字乳腺摄影系统进行X线发生器性能质量控制检测与评价；分别应用直接数字化X线摄影技术（DR）、相位对比乳腺摄影（PCM）和计算机X线摄影技术（CR）系统在4个厚度下（30、40、50及60mm）对乳腺专用对比度细节检测模体（CDMAM3．4）进行AEC曝光成像，计算与评价每一厚度下的平均腺体剂量（AGD）和影像质量因子（IQF）。结果DR和CR的X线机性能检测符合现有标准；等效PMMA厚度分别为30、40、50、60mm时，DR系统的AGD分别为1．20、1．42、1．75、2．20mGy；PCM系统AGD分别是0．82、1．19、1．33、1．70mGy；CR系统AGD为0．59、0．88、1．47、2．19mGy。在相应的模体厚度下，DR系统的IQF值为21．36、21．57、27．25和30．58；PCM和CR系统的IQF值分别为28．02、29．10、35．90、41．24和39．78、39．30、43．85、48．08。结论GBZ186—2007标准不适用于PCM系统X线机性能部分性能的评价。本研究的3套系统自动曝光下平均腺体剂量均符合欧洲标准。在国内检测规范欠缺的情况下，可参考国际标准或指南对数字乳腺系统进行常规监测。

Objective To carry out the quality control testing and evaluation for three digital mammography systems. Methods The performance of three digital mammography systems was assessed by applying methods recommended in the European guidelines for quality assurance in breast cancer screening and diagnosis and Chinese specification for testing of quality control in X-ray mammography. The performance of X-ray generator of three digital mammography systems were tested and evaluated. CDMAM 3.4 phantom with four different thickness （ 30,40,50,60 mm） were exposured in DR, PCM, and CR system, respectively. The average glandular dose （AGD） value was measured and image quality figure （IQF） analysis was performed in each thickness. Results The X-ray machine performance of DR and CR was in accordance with existing standard, however the standard was inappropriate to evaluate part of X-ray machine performance of PCM system. The AGDs for system DR were 1.20, 1.42, 1.75 and 2.20 mGy for 30, 40, 50 and 60 mm PMMA thickness, respectively. The respective AGDs for system PCM and CR were 0.82, 1.19, 1.33, 1.70 mGy and 0.59, 0.88, 1.47, 2. 19 mGy. For the same phantom thickness sequence, the IQFs were 21.36, 21.57, 27.25 and 30.58 for system DR, 28.02, 29. 10, 35.90, and 41.24 for system PCM, whereas they were 39.78, 39.30, 43.85 and 48.08 for system CR. Conclusions The AGDs of all three systems were in accordance with the values recommended in European guideline. The AGD and IQF could provide an effective way for performance assessment and constancy checks for digital mammography systems.