我国乳腺X射线摄影受检者乳腺剂量水平调查研究

Research on Glandular Dose Level of Mammography in China

目的通过调查全国15个省市不同级别医疗机构乳腺X射线摄影曝光参数并测量计算受检者乳腺平均剂量,分析我国乳腺X射线摄影中受检者压迫后乳房厚度分布及乳腺受照剂量水平,为建立适合我国成年女性受检者乳腺X射线摄影的剂量指导水平提供依据。方法按照《医用辐射危害评价与控制技术研究》实施方案的要求,调查临床实际乳腺摄影受检者的年龄、乳房压迫厚度、曝光参数、摄影体位等相关信息,通过手动曝光测量该条件下乳房压迫厚度处的入射空气比释动能(Ka,i),计算受检者的乳腺平均剂量(AGD)。结果共在全国15个省的149家医院调查了4372例乳腺X射线摄影体位,273台不同类型乳腺X射线摄影设备,包括屏片乳腺X射线摄影、计算机乳腺X射线摄影(乳腺CR)和直接数字乳腺X射线摄影(乳腺DR)设备,对于这三种类型的设备,头尾(CC)位投照时受检者AGD的平均值分别为1.21,1.77,1.61 m Gy,AGD的75%位分别为1.36,2.22,1.81 m Gy;斜侧(MLO)位时受检者AGD平均值分别为1.02,1.78,1.66 m Gy,AGD的75%位分别为1.23,2.46,1.81 m Gy。CC位和MLO位时乳房压迫厚度的中位数分别为4.2和4.5 cm。结论不同类型乳腺X射线摄影设备中,屏片乳腺X射线摄影设备致受检者的乳腺平均剂量最低,其次是乳腺DR设备,乳腺CR设备致患者剂量最高。

Objective To analyze the distribution of compressed breast thickness（ CBT） and dose level of average glandular dose（ AGD） by the investigation of exposure parameters of mammography and measurement of AGD in different levels of hospitals in 15 provinces of China,and provide basis to establish a suitable diagnostic reference level（ DRL） of mammography for adult female in China. Methods According to the requirements of the ＂Research on Radiation Hazard Evaluation and Control Technology of Medical Radiation＂,we investigated the age,the CBT,the exposure parameters and the position of clinical mammography cases. The incident air kerma（ Ka,i） was measured by manual exposure according to the exposure records,and AGD was calculated using the method of EC guideline. Results A total of 4,372 mammograms and 273 different types of mammography equipments were investigated in 149 hospitals in 15 provinces of China,including screen- film mammography,computed radiography for mammography and digital mammography. For the three types of equipment,the mean value of AGD of craniocaudal（ CC） position was1. 21,1. 77,1. 61 m Gy,and 75 th percentile of the AGD was 1. 36,2. 22,1. 81 m Gy,respectively; the mean value of AGD of mediolateral oblique（ MLO） position was 1. 02,1. 78,1. 66 m Gy,and 75 th percentile of the AGD was 1. 23,2. 46,1. 81 m Gy,respectively. The median of CBT for CC and MLO was 4. 2 and 4. 5 cm respectively. Conclusion The AGD of SFM is the lowest among different types of mammography equipment,followed by mammary DRM. The AGD of mammary gland CRM is higher than SFM and DRM.