摘要
目的探讨计算机X线摄影(computed radiography,CR)的合理曝光条件。材料与方法以10mAs、20mAs、40mAs档,分别从50～150kV、步长为2kV对实验猪胸部进行系列曝光,用剂量计记录每次曝光的入射点的入射X线剂量、肺野和纵隔处的透射X线剂量,得到三个序列的X线剂量与kV的关系数据,绘制入射剂量、透射剂量与kV的关系图,然后用相同的步骤进行系列胸部正位CR摄影,以噪声不影响观察为前提,找出曝光量最低的CR图像及其对应的合理曝光剂量,分析合理曝光剂量与曝光条件的关系。结果(1)合理曝光条件对透射剂量有很强的依从关系,不管如何改变kV和mAs的组合,合理透射剂量均是一个相对的恒定值,三个序列间合理剂量差异性比较均无统计学意义(P>0.05);(2)合理曝光剂量相对应的入射剂量,低mAs高kV组合要比高mAs低kV组合的入射剂量低,三个序列间差异比较具有统计学意义(P<0.01);(3)入射点剂量与mAs呈正相关。结论(1)对于CR来说,透射剂量是合理曝光条件唯一考量的参数;(2)提高kV对降低患者辐射剂量有意义。
Objective To investigate the reasonable X-ray exposure conditions of Computed Radiography （CR）. Materials and Methods Series of exposure conditions,including 10mAs,20mAs and 40mAs current,voltage from 50kV to 150kV with 2kV step length,were performed on the chest of experiment pigs.Every time,incident X-ray exposure dose and transmission X-ray dose after the lung field and mediastinum were recorded using X-ray dosimeter.The relationship map between X-ray dose and KV data was obtained.The lowest exposure CR image and the corresponding reasonable exposure dose were identified. Results （1）Reasonable conditions had strong dependence of the transmission dose. Regardless of combination modes of kV and mAs,reasonable transmission dose was a relatively constant value.（2）Lower mAs combinated with higher kV had lower incident dose than higher mAs combinated with lower kV（P0.01）.（3） Positive correlation existed between point of the incident dose and the mAs. Conclusion （1）As for CR Photography,the transmission dose was the only consideration of reasonable exposure conditions.（2） It was meaningful to to reduce the radiation dose by increasing KV.
出处
《临床放射学杂志》
CSCD
北大核心
2010年第5期683-686,共4页
Journal of Clinical Radiology
基金
广西壮族自治区卫生厅自筹经费科研课题(z2007092)
关键词
计算机X线摄影
曝光剂量
合理曝光条件
Computed radiography Exposure dose Reasonable exposure conditions
