全野数字乳腺X线摄影降低辐射剂量的初步研究  

A preliminary study of exposure dose reduction in full-field digital mammography

作　　者：张静[1] 汪登斌[1] 王媛 李惠民[1] 王丽君[1] 江怡菲 

机构地区：[1]上海新华医院,上海200092 [2]上海GE(中国)有限公司,上海200000

出　　处：《放射学实践》2015年第7期755-758,共4页Radiologic Practice

摘　　要：目的：探讨全野数字乳腺X线摄影的曝光条件,找出影响图像质量和平均腺体剂量（AGD）的因素,为乳腺摄影提供参考。方法：采用GE全野数字乳腺X线机对fluke NA 18-220乳腺模体进行摄影,首先采用AOP模式下的标准模式曝光,压力设定为12daN,厚度为42mm,结果形成28kV,45mAs,Mo/Rh曝光条件,以此为参照基准,设定两组实验：以管电流为单变量,设值为8~90mAs（间隔为机器旋钮可调节的数值）;以管电压为单变量,设值为22~36kV（间隔为1）,曝光并记录AGD值。上述过程重复3次取平均值。2位影像学医师和1位技师分别独立进行软阅读,参照美国放射学会评分标准,对模体中钙化点、尼龙纤维、肿块灶的显示进行评分。结果：与自动曝光模式相比,手动曝光模式管电压下降3kV,管电流下降20mAs,影像质量符合诊断标准,辐射剂量有效下降。管电压的变化对AGD的影响比管电流要大。结论：以自动条件作为参照标准,在保障图像诊断质量前提下,管电压和管电流可分别有效降低,以减少辐射。Objective：To explore the radiation dose in full-field digital mammography and find out the impact factors in image quality and average glandular dose（AGD）to provide valuable exposure parameters setting for mammography.Methods：The NA18~220 mammography phantom was exposured by GE Senography DS full-field digital mammography with the standard（STD）mode of automatic optimization of parameter（AOP）system（pressure：12daN;thickness：42mm）.Three exposure parameters（28kV,45 mAs,target/filter：Mo/Rh）were acquired as a reference.Firstly,tube current as a variable parameter was ajusted from 80 mAs to 90 mAs.Then,tube potential wass increased step by step from 22 kV to 36 kV with 1kV interval.All images obtained from three groups were evaluated by three radiologists according to the criterion of American college of radiology.The number of calcification,nylon fibers and masse shown on the image and the value of AGD were recorded.Results：Compare to AOP system,the image quality was clinically acceptable in the range of 3kV decreace in tube potential and 20 mAs decrease in tube current,the radiation dose was optimized effectively.The increase in tube voltage potential were prone to achieve better image quality and rising of AGD,compared with increase in tube current.Conclusion：To maintain the acceptable image quality,the reduction in radiation dose can be achieved by reasonable decreasing tube current and tube potential.

关 键 词：X线 数字乳腺摄影 曝光剂量 影像质量 平均腺体剂量 

分 类 号：R737.9[医药卫生—肿瘤] R730.44[医药卫生—临床医学]