高能辐射照相中屏片系统的响应特性  

Monte carlo simulation of screen-film system used in high energy radiography

作　　者：刘军[1] 杨光志[2] 刘进[1] 

机构地区：[1]中国工程物理研究院流体物理研究所,四川绵阳621900 [2]西南计算中心,四川绵阳621900

出　　处：《信息与电子工程》2009年第3期230-234,共5页information and electronic engineering

基　　金：国防科技基础研究基金资助项目(426020402)

摘　　要：为了获得更高的底片图像空间分辨率,在"屏片"图像接收系统成像原理的基础上,讨论了薄介质中能量沉积的模拟方法。针对实际照相模型,研究了直穿光子和散射光子在"屏片"系统中的响应特性。结果表明,对于"屏片"系统,金属增感屏出射面的电子通量是决定X射线能量转换效率的主要因素。适当增加金属增感屏的厚度,有助于降低散射的影响,但也在一定程度上增加了图像本底。当金属增感屏厚度为0.4 mm左右时,金属增感屏对直穿光子的局部增感效果最好。The method of calculating the deposited energy of high energy x-ray in thin material such as film emulsion is discussed according to imaging theory of screen-film system. Response characteristics of screen-film system to primary and scatter photon are studied. It is shown that：（1） energy conversion efficiency of x-ray in screen-film system is mainly determined by the flux of electron emitted from the metal intensifying screen; （2） the reasonable increasing of the thickness of metal intensifying screen can reduce the effect of scatter photon, whereas in a manner increases the image background; （3） the local intensifying efficiency is almost the biggest as the thickness of metal intensifying screen is 0.4 mm.

关 键 词：屏片系统 能量沉积 转换效率 点扩展函数 

分 类 号：R812[医药卫生—放射医学]