Upon a request for sharing radiation dose information, a hospital A transmits first specification data (30a) of a first X-ray imaging system (2a) to a hospital B. The first specification data (30a) is written to a storage device (22b) of the hospital B. The storage device (22b) stores absorption data (50) and second specification data (30b), besides the first specification data (30a). A storing and retrieving processing unit (40) outputs the first and second specification data (30a, 30b) to an arithmetic section (46). Also, the storing and retrieving processing unit (40) retrieves absorptance corresponding to the type of used intermediate member from the absorptance data (50), and sends a retrieval result to the arithmetic section (46). The arithmetic section (46) converts a first optimal dose used in the first X-ray imaging system (2a) into a second optimal dose suitable for specifications of a second X-ray imaging system (2b), based on data transmitted from the storing and retrieving processing unit (40).
