Assessment of PACS in the management of images in radiation therapy

To assess the value of a Picture Archiving and Communication System (PACS), the management of image data in the division of radiation therapy was analyzed. Nine hundred patients were randomly selected from among those who had undergone radiation therapy at Kyoto University Hospital. They were representative of three periods: before the use of CT; after the use of CT, but prior to the use of MRI; and after the use of MRI. Analysis of taking, keeping, and using images revealed the following: (1) The size of memory required for one patient was increased from 33.8 MB to 48.8 MB by the introduction of CT and MRI. (2) Ninety-seven percent of the patients were from other departments or hospitals. A film library had been used to keep the images, but complete film-keeping was achieved for no more than twenty percent of the patients when compared with a PACS which was installed at the hospital. (3) The mean duration of follow-up after treatment was 24.9 months, and previous simulation images were required for 14% of the patients due to retreatment after considerable intervals. Our study confirmed that a reliable method of long-term image data is a necessity in the division of radiation therapy. (4) We found that a PACS can be effectively utilized because newly-registered patients represent only a small proportion of all diagnostic radiology patients. In conclusion, a PACS is useful to our department of radiation therapy. (author)