An X-ray CT system (1000) includes a CT scanner (300) which obtains diagnostic images of a patient, a chemical liquid injector (100) which injects a chemical liquid into a patient whose images are obtained, an operation device (400), I/Fs (320, 421) for transmitting and receiving data between the CT scanner (300) and the operation device (400) and I/Fs (120, 420) for transmitting and receiving data between the chemical liquid injector (100) and the operation device (400). The operation device includes an input section used to set an injection condition for the chemical liquid by the chemical liquid injector (100) and an imaging condition by the CT scanner (300), a control section for controlling operation of the chemical liquid injector (100) and operation of the CT scanner (300) in accordance with the setting and a display section (450) for displaying information relating to the setting of the injection condition and the imaging condition and an obtained image.