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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 study the response of flat panel detector (FPD) to kV and mAs. Methods Using the DR system produced by HOLOGIC Corporation, the photography condition was changed and the original gray value of each point was measured by the function of the system software. The variation rule was found by comparison to provide guidance for the selection of photography conditions. Results Within 100kV, the original grayscale value of the image increased almost linearly with the increase of the kV value. When the value of the grayscale value exceeded 100kV, the gray value of the image increased obviously with the increase of kV. Nearly linear response characteristics. Conclusion The best kV value of chest digital radiography is about 100kV. Do not just increase the gray value of the image by increasing the kV value (except for the high kV photography), so that the gray value of the image can be increased or decreased according to the variation of the mA and the exposure time, and the rational selection With the photography conditions, to avoid unnecessary radiation damage.