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 became more important to maintain the quality
of CRT monitors. In this study, we evaluated the luminance characteristics
of CRT monitorsin cineradiographic systems by mesuring 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 relativ
luminance increased, when the contrast volume control (CVC) was steped
up in the controlled condition for brightness volume control (BVC). (2)
The gradiant of the luminance curve decreased even though relative luminance
increased, when BVC was steped up in the controlled condition for CVC.
(3) We measured the luminance characteristics of the CRT monitors of various
insttitutions under usual conditions and found that the luminance curves
differed for each CRT monitor according to the varius adjustments made
in each institution. However, when we adjusted the CRT monitors for the
same conditions, almost all of the 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 institution
differed from one another in spite of adjustments for the same condition
when we exporsed X-rays that penetrated a copper plate (2mm) to the imaging
intensifier. We concluded that the intensities of video signals in cineradiographic
Quality control of CRT (cathode ray tube) monitors is essential to the
good management of cineradiographic systems. In this study, we developed
a new video signal generator and measured the output luminance of 35 systems
in our five institutes. The results were as follows:
1. Our video signal generator (GV-812) may be useful in quantitatively
analyzing the luminance of CRT monitors.
2. There were large differences in luminance among CRT monitors in the
clinical setting. The gradient of the video signal-luminance curve ranged
between 1.38 and 2.91. The coefficient of variation ranged from 8% to 22%.
3. The life of CRT monitors may be indicated by periodically measuring
the decline curve of luminance under the usual setting and the maximum
contrast value, using the video signal generator.