基于乳腺模体的不同曝光模式数字化乳腺X线摄影辐射剂量和图像质量的研究

Research on the correlation of radiation dosage and image quality in digital DR mammography with different exposure modes

目的探讨全数字化乳腺X线摄影中不同曝光模式对辐射剂量和图像质量的影响。方法使用数字乳腺机、配套后处理工作站和5 M高分辨率医用显示器,分别采用智能自动曝光控制(smart-AEC)、常规自动曝光模式(Automatic)、手动曝光模式(Manual)对乳腺模体进行检查,获得平均腺体剂量(AGD)、皮肤入射剂量(ESE)、信噪比(SNR)、对比噪声比(CNR)和品质因素(FOM),并对比模体影像中的肿块、条索及钙化的检出数量。结果smart-AEC曝光模式的AGD和ESE,分别是0.63 mGy和2.065 mGy,高于Automatic模式的0.53 mGy和1.724 mGy以及Manual模式的0.59 mGy和1.932 mGy。smart-AEC曝光模式的SNR、CNR和FOM分别是26.14、1.59和4.02,高于Automatic模式的24.92、1.43和3.86以及Manual模式的25.90、1.52和3.92。smart-AEC模式对肿块、条索及钙化的检出率均是100%,Automatic模式的检出率分别是80%、100%和100%,而Manual模式的检出率分别是100%、66.7%和100%。结论与Automatic、Manual相比,smart-AEC是全数字化乳腺X线摄影检查的最佳曝光模式。

Objective To discuss the correlation of radiation dosage and image quality in digital DR mammography with different exposure modes.Methods By use of digital DR mammography,supporting post-processing workstation,high resolution medical display,the mammographic phantom was exposed by smart-AEC,Automatic,Manual.The entrance skin exposure(ESE),average glandular dose(AGD),the signal-to-noise ratio(SNR),contrast-to-noise radio(CNR)and figure of merit(FOM)were recorded and measured.The number of tumors,striations and calcifications in the imagings of mammographic phantom were compared.Results The AGD and ESE of smart-AEC are 0.63 mGy and 2.065 mGy,which are higher than 0.53 mGy and 1.724 mGy of Automatic,0.59 mGy and 1.932 mGy of Manual.The SNR,CNR and FOM of smart-AEC are 26.14,1.59 and 4.02,which are higher than 24.92,1.43 and 3.86 of Automatic,25.90,1.52 and 3.92 of Manual.The detection rates of tumors,striations and calcifications for smart-AEC are all 100%.The detection rates for Automatic are 80%,100%and 100%,and the detection rates for Manual are 100%,66.7%and 100%.Conclusion Compared with Automatic and Manual,smart-AEC is the best exposure mode for full digital mammography.