With the spread of interventional radiology(IVR), an increasing number of cathode ray tube(CRT)monitors are being used with digital cineradiographic systems. Therefore, it has become more important to maintain the quality of CRT monitors. In this study, we evaluated the luminance characteristics of CRT monitors in cineradiographic systems by measuring luminance with a video signal generator and luminance meter. We obtained the following results: (1)The gradient of the luminance curve was constant even though relative luminance increased, when the contrast volume control(CVC)was stepped up in the controlled condition for brightness volume control(BVC). (2)The gradient of the luminance curve decreased even though relative luminance increased, when BVC was stepped up in the controlled condition for CVC. (3)We measured the luminance characteristics of the CRT monitors of various institutions under usual conditions and found that the luminance curves differed for each CRT monitor according to the various adjustments made in each institution. However, when we adjusted the CRT monitors for the same conditions, almost all of them showed similar luminance curves.(Results for 1, 2, and 3 were obtained from stand-alone CRT monitors.)(4)The luminance of CRT monitors connected to cineradiographic systems in various institutions differed from one another in spite of adjustments for the same condition when we exposed x-rays that penetrated a copper plate(2 mm)to the image intensifier. We concluded that the intensities of video signals in cineradiographic systems differ.
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