McLean D, Gray J E, Swensen S J, Vrieze T J
School of Medical Radiation Technology, University of Sydney, Australia.
Eur J Radiol. 1998 Mar;27(1):53-60. doi: 10.1016/s0720-048x(97)00033-8.
To determine the sensitometry and 'cross-talk' of a twin screen-film cassette and to assess its clinical potential.
The twin cassette utilises two sets of screens, divided by filter material, to provide an optimised image of the mediastinum and the lungs. The exposure difference for the two images was measured sensitometrically. The contribution to film density of visible light and K-characteristic radiation, from adjacent screens in the absence of a dividing filter, was investigated.
Clinical experience indicated that an exposure difference of 3.4 between the front and back screens, was optimal. Visible light and K-characteristic radiation from the front screens, contributed up to 20 and 24% respectively, of the back film exposure and screen absorbed energy respectively. This was reduced to 0 and 6% with the use of the filter.
The twin screen-film cassette provides extended latitude to enable optimal visualisation of the lung and mediastinal regions. Adjacent screen 'cross-talk' has been overcome to allow standard and portable chest applications.
确定双屏-胶片暗盒的感光测定和“串扰”情况，并评估其临床应用潜力。
该双暗盒利用两组由滤光材料分隔的屏，以提供纵隔和肺部的优化图像。通过感光测定法测量两张图像的曝光差异。研究了在没有分隔滤光片的情况下，相邻屏发出的可见光和K特性辐射对胶片密度的影响。
临床经验表明，前后屏之间3.4的曝光差异最为理想。前屏发出的可见光和K特性辐射分别对后片曝光和屏吸收能量贡献高达20%和24%。使用滤光片后，这一比例分别降至0%和6%。
双屏-胶片暗盒提供了更大的宽容度，能够实现肺部和纵隔区域的最佳可视化。相邻屏的“串扰”问题已得到解决，可用于标准胸部和便携式胸部检查。
