摘要
目的研究平板探测器(FPD)对kV、mAs的响应特性。方法使用HOLOGIC公司生产的DR系统,变换摄影条件,通过系统软件功能测出设定各点的原始灰度值,通过比较发现其变化规律,为摄影条件的选择提供指导。结果在100kV内,影像的原始灰度值随着kV值的增加而近乎呈线性增加,而大于100kV后,影像的灰度值随着kV增加而增加的幅度明显下降;FPD对mA和曝光时间的响应特性几近线性。结论胸部数字X射线摄影的最佳kV值在100kV左右。在kV满足穿透力的前提下,不要只通过增加kV值来提高影像的灰度值(高kV摄影除外);要配合mA和曝光时间的变化来增加或降低影像的灰度值,合理化选择摄影条件的搭配,避免不必要的辐射损伤。
Objective To find out the response characteristics of flat panel detector (FPD) to kV and mAs by means of the experiments. Methods With the digital radiography (DR) system produced by HOLOGIC Company,the exposure parameters(kV,mAs,t, etc.) were changed,the gray value of the points designed before the experiment were measured,and then the data were analyzed to find out the changing pattern to guide the radiographic parameters selected. Results The image gray value of the pixels increased almost linearly in accordance with the increase of kV within 100 kV,but the gray values increased slowly beyond 100 kV.The gray value of the pixels increased almost linearly while the mA and exposure time increased individually. Conclusion^The reasonable kV utilized in chest digital radiography should be 100 kV or so.Not only to elevate the kV in order to increase the gray values if the passing-ability of X-ray is enough,but also to elevate the mA or to prolong exposure time respectively(except for high kV radiography).The radiographic parameters should be selected reasonably so that the radiation dose absorbed by both patient and radiographer could be reduced.;
出处
《中华放射医学与防护杂志》
CAS
CSCD
北大核心
2005年第2期188-190,共3页
Chinese Journal of Radiological Medicine and Protection
