1. An image processing apparatus comprising: an acquiring unit that acquires information of a relative position between a radiographic space where a subject is radiographed by an X-ray diagnosis apparatus and a scanning space where the subject is scanned by an ultrasound probe; and a determination unit that determines a position almost the same as the position scanned by the ultrasound probe in the radiographic space, according to the information of the relative position acquired by the acquiring unit, wherein the acquiring unit acquires the information of the relative position based on an X-ray image radiographed by the X-ray diagnosis apparatus.