乳腺计算机X射线摄影图像质量和剂量最优化研究  

Optimization of image quality and radiation dose in CR ammography

作　　者：徐辉[1] 宛然[2] 宋鲁新[2] 王建超[1] 岳保荣[1] 

机构地区：[1]中国疾病预防控制中心辐射防护与核安全医学所,北京100088 [2]北京大学第一医院医学影像科,北京100034

出　　处：《中国医学影像技术》2013年第7期1197-1201,共5页Chinese Journal of Medical Imaging Technology

摘　　要：目的比较数字乳腺系统中手动曝光与自动曝光控制(AEC)下图像质量的差异,观察图像后处理在改善图像质量和降低受检者辐射剂量方面的作用。方法分别选用CDMAM 3.4模体和TORMAM模体,在一套乳腺CR系统中选取5个不同厚度,每一个厚度分别为1次全自动曝光和3次手动曝光,手动曝光的剂量分别为AEC剂量的80%、60%和40%。由3名放射技师对模体影像进行2次评分,一次直接对原始图像评分;另一次对图像进行后处理以符合最佳显示条件并评分。比较手动低剂量曝光的影像与AEC曝光的影像质量的差异。结果 CDMAM 3.4模体中影像质量因子(IQF)测值表明,经过后处理的图像质量优于未处理时,部分低剂量图像的质量经过处理后优于AEC曝光剂量的图像。对于不同厚度的模体,通过手动改变曝光参数降低曝光量以及图像后处理,可降低受检者辐射剂量20%～60%。在TORMAM模体中,图像后处理对于纤维丝细节和圆形细节改善显著(P<0.001),而对于颗粒群细节无明显改善(P=0.74)。结论乳腺CR数字摄影中,通过图像后处理可以改善图像质量,并在保持图像质量的同时降低受检者辐射剂量。Objective To investigate the difference of image quality between automatic exposure control（AEC） and manual exposure in CR digital mammography,and to observe the effect of image post-processing on improvement of image quality and dose reduction.Methods CDMAM 3.4 phantom and TORMAM phantom were selected and exposed in a CR system in 5 different phantom thickness.Under each thickness there were 4 dose levels（once automatic and 3 times manual exposures,which corresponded to 80%,60% and 40% dose）.Three observers interpreted all the images.Each image was scored twice with unprocessed images and post-processed image.The differences of image quality were compared between 3 lower dose images and 100% dose image.Results The results of image quality figure（IQF） of CDMAM phantom showed the image quality of post-processed images were higher than unprocessed images.Part of the lower dose images exceeded AEC dose image in image quality through post-processing.The dose decreased from 20% to 60% through image post-processing in different equivalent breast thickness.From the results of TORMAM phantom,for the detection of filament details and circular details,the scores increased after post-processing（P0.001）.However for the partical details,the effect of image post-processing on image quality was not obvious（P=0.74）.Conclusion In CR digital mammography,the image quality can be improved through image post-processing.Radiation dosage can decrease through the image post-processing without reduce of image quality.

关 键 词：乳腺数字摄影 图像后处理 辐射剂量 

分 类 号：TP317[自动化与计算机技术—计算机软件与理论] R445[自动化与计算机技术—计算机科学与技术]