摘要
目的 比较遮幅观片灯与普通观片灯的阅片效果 ,评价遮幅观片灯在影像诊断质量保证中的价值。方法 (1)将 30张带有低对比度微小信号的X线片 (每张照片上的信息量为随机设置 )分别置于遮幅观片灯和普通观片灯上 ,请 3位放射科医师在不同观片灯亮度下进行识读 ,统计信号读出率并绘制特性曲线 ;(2 ) 5张曝光过度的X线片分别在遮幅观片灯和普通观片灯上进行阅片诊断比较。结果 (1)高密度X线片信号读出率平均提高 2 3 0 % (最大 2 9 6 % ,最小 13 7% ) ,识读效果明显优于普通观片灯 (χ2 ≥ 18 0 9,P <0 0 0 5 ) ;低密度片次之 ,信号读出率平均提高 11 0 4% (最大 14 6 % ,最小 3 3% ) ,识读效果优于普通观片灯 (χ2 ≥ 8 2 0 ,P <0 0 0 5 ) ;而对中密度片效果不明显 (χ2 ≤ 0 5 0 ,P >0 0 5 ) ;(2 )普通观片灯上 ,5张X线片均因胶片密度的对比度太小、影像模糊而不易识读 ;遮幅观片灯则显示出影像细节而得以诊断。结论 遮幅观片灯可使胶片所记录的影像信息充分显示 ,为临床医师提供更多的诊断依据 ,因此在影像诊断质量保证中具有重要价值 ,应予推广。
Objective To evaluate the masked viewbox in quality assurance of imaging diagnosis by comparing the effect of detecting small low contrast signals on films with conventional unmasked viewboxes Methods (1) Thirty films were viewed on masked and unmasked viewboxs by three doctors when illumination ranged from 200 lx to 8 000 lx, the ratio of signals′ finding was calculated The film densities were 2 0 or 1 0 or 0 4, each called high D and middle D and low D films respectively (2) Viewing 5 overexposed films on the masked viewboxs compared the diagnostic resultes with unmasked one Results (1) The high D film′s ratio of signals′finding was raised with averages of 23 % (the highest value was 29 6%,and the lowest value was 13 7%), and the low D film′s ratio of signals ′finding was raised with averages of 11 04% (the highest value was 14 6%,and the lowest value was 3 3%), there were remarkable difference between masked and unmasked viewboxs (χ 2≥18 09, P <0 005 and χ 2≥8 20、 P <0 005) However,with the middle D film′s ratio of signals′ finding there was no remarkable difference between masked and unmasked viewboxes (χ 2≤0 50, P >0 05) (2) In 5 overexposed films , it was difficult to diagnose on the unmasked viewboxes But on the masked viewbox, all the 5 overexposed films could be used for diagnosis at high illumination Conclusion Masked viewbox can show more useful details for diagnosis than unmasked viewbox, thus improving diagnostic quality , it should be employed in routine diagnosis
出处
《中华放射学杂志》
CAS
CSCD
北大核心
2000年第2期122-125,共4页
Chinese Journal of Radiology
关键词
视听设备
X线胶片
质量控制
遮幅观片灯
Audiovisual aids
X-ray film
Optics
Quality control
Evaluation studies
