计算机X线摄影中优化摄影条件的测试探讨

Investigation of optimized radiographic parameter in a computed radiography system

目的 :探讨计算机X线摄影 (computedradiography ,CR)条件的优化 ,提高CR摄影图像质量的影响。方法 :应用CR系统获取铝梯影像 ,在相同像素值条件下 :①改变kV ,求所需mAs;②在相同光条件下求各阶铝梯影像间的像素值平均偏差及平均偏差减量。结果 :①kV值分别为 5 0、6 0、70、80、90、10 0、110、12 0时 ,所需mAs分别为 80、2 2、9、4 .5、2 .5、1.8、1 2、1.0 ;②在相同光条件下 ,对应于各阶铝梯影像间的像素值平均偏差依次为 73.1、5 7.6、5 0 .4、4 4 ,4、39.6、36 .0、33.6、32 0 4。像素平均偏差减量依次为 15 .5、7.2、6 .0、4 .8、3.6、2 .4、1.2。结论 :在相同影像像素值情况下 ,随kV增加 ,CR摄影所需mAs降低 ,阶铝梯影像间的像素值平均偏差及平均偏差减量影像降低 ,影像对比度下降。

Objective:To study how to optimize radiographic parameter and to improve on imaging quality in a computed radiography system.Methods:Imaging plate was exposed and an aluminium ladder was imaged with the same pixel value of its sixth scale. We changed kV value and obtained mAs and the average density deviations and their deductions in aluminium ladder image.Results:When the value of kV is 50,60,70,80,90,100,110,120 respectively,its corresponding mAs is 80,22,9,4.5,2.5,1.8,1.2,1.0.the average density deviations in aluminium ladder image are 73.1,57.6,50.4,44.4,39.6,36.0,33.6,32.4.Conclusion:At the same pixel value, with increasing of kV, mAs will decrease, also the average density deviations in aluminium ladder image and their deductions decrease, and contrast will be digraded.