数字X射线摄影机房内散漏射线的空间分布

Study on the spatial distribution of scattering and leaking ray inside digital radiography room

目的研究医用诊断X射线数字摄影机房内散漏射线剂量大小的空间分布情况，为新建、改建、扩建医用诊断X射线机房的屏蔽防护设计提供参考依据。方法以X射线球管为中心，分别采用水平与垂直两种照射方式，测量机房内离球管不同距离及不同方向的散漏射线空气比释动能率。结果在同一方向情况下，离球管1～2m处的散漏射线空气比释动能率处于最高水平，且保持相对稳定状态。在同样距离的情况下，当水平方向照射时，与主射线束成45°、90°、270°、315°方向的散漏射线空气比释动能率较高，180°方向最低；当垂直方向照射时，球管左右两侧的散漏射线空气比释动能率较高，球管正面略低，球管背面最低。结论机房内散漏射线的空间分布出现剂量大小与球管距离不成平方反比的衰弱现象。

[ Objective] To study the spatial distribution of scattering and leaking ray inside medical diagnostic X-ray digital photog- raphy room, provide reference for shielding protection design of the new construction, reconstruction and expansion of medical diag- nostic X-ray room. [ Methods ] X-ray irradiation was performed by horizontal way and vertical way respectively, the air kerma rate of the scattering and leaking ray was measured at different distances and different directions from the tube. [ Results ] In the same di- rection, the air kerma rate of the scattering and leaking ray 1-2 meters away from the X-ray tube was the highest, and it maintained a relatively steady state. In the same distance with horizontal direction radiation, the air kerma rates of the scattering and leaking ray in the direction of 45°, 90°, 270° and 315° to the main ray beam were higher, and that in the direction of 150° was the low- est. With vertical direction radiation, the air kerma rates of the scattering and leaking ray on the left and right sides of X-ray tube were higher, that front X-ray tube was slightly low and it was the lowest on the back of tube. [ Conclusion ] The dose of scattering and leaking ray has the reduction trend with the distance to the tube, and there is not a squared inverse relationship.