1. An image processing apparatus, comprising: processing circuitry configured to acquire 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 determine a position almost a same as a position scanned by the ultrasound probe in the radiographic space, according to the information of the acquired relative position, wherein the processing circuitry is further configured to acquire positional information of the ultrasound probe in the radiographic space based on an X-ray image of the ultrasound probe mounted on a table of the X-ray diagnosis apparatus and radiographed from one direction, and a geometry of the X-ray diagnosis apparatus, acquire positional information of the ultrasound probe in the scanning space corresponding to a position where the X-ray image is radiographed, and acquire the information of the relative position based on the positional information of the ultrasound probe in the radiographic space and the positional information of the ultrasound probe in the scanning space.