To obtain images representing true collection of medical solution to a cancer region or the like, which are not affected by excretion, secretion, etc.

An image reconstruction equipment 23 reconstructs an image from data collected into a data collection memory 21 at a first measurement after a medical solution is administered to a subject to be tested. The image data is stored in an image memory 24. A second measurement is carried out after a lapse of time, and data is collected to the data collection memory 21. Image data reconstructed from the data by the image reconstruction equipment 23 is stored in an image memory 25. The image data stored in the image memories 24 and 25 are compared with each other by an arithmetic unit, whereby the data of a part which changes greatly is excluded.