[en] Cathode-ray tube (CRT) provides the best functions and performance as regards every electric display under the present circumstances; Therefore, it is one of the key technology for a system to improve in the quality, maintain the performance and control of CRT images when we construct and drive forward with filmless-PACS. However, CRT images are far inferior to a hard copy of CR (computed radiography) ones at present. However, if we process CRT images with better photographic conditions regarding the necessary parts of image with suitable image frequency and gradient processing or magnified viewing function, the detectability of CRT image would be closer to be the same as a CR hard copy or better. In the future, we need to establish optimization in more detail regarding the data collecting method for finding abnormal and on setting up better image disposal conditions or image processing. Hopefully, CRT will be developed much more as various types of software for diagnosis and applications progresses. (author)