McLean D, Gray J E
School of Medical Radiation Technology, University of Sydney, N.S.W., Australia.
Eur J Radiol. 1996 Feb;21(3):212-6. doi: 10.1016/0720-048X(95)00729-A.
To determine whether the scatter-to-primary (s/p) ratio, measured on a screen-film or computed radiographic (CR) system, varies with chemical composition or primary attenuation properties.
The s/p ratios of four Gd2O2S screens, three CaWO4 screens and a CR screen, were determined under uniform irradiation conditions. One simulated low scatter conditions, such as in lung imaging, and the other simulated high scatter conditions as in abdominal imaging. The absorption efficiency of each screen was measured and calculated.
The measured s/p ratio varied within each set of screens. The s/P ratio was related to the absorption efficiency of primary radiation for the screen-film and CR system. No difference in the s/p ratio was seen between screen-film and CR systems when normalised for the primary absorption efficiency.
Absorption efficiency of the imaging system is a major indicator of s/p ratio, for both screen-film and CR systems.
确定在屏-片或计算机X线摄影（CR）系统上测量的散射与一次射线（s/p）比值是否随化学成分或一次射线衰减特性而变化。
在均匀照射条件下测定了4种硫氧化钆屏、3种钨酸钙屏和1种CR屏的s/p比值。一种模拟低散射条件，如肺部成像；另一种模拟高散射条件，如腹部成像。测量并计算了每种屏的吸收效率。
每组屏内测量的s/p比值有所不同。s/P比值与屏-片和CR系统对一次射线的吸收效率有关。当根据一次射线吸收效率进行归一化处理时，屏-片系统和CR系统之间的s/p比值没有差异。
对于屏-片系统和CR系统而言，成像系统的吸收效率是s/p比值的主要指标。
