Patent ID: 8197137

Claim:
An X-ray imaging apparatus comprising: an X-ray irradiation unit, including a generation unit which generates X-rays and a collimator including a stop to define a beam spread angle of the generated X-rays, configured to irradiate an object with X-rays at an arbitrary position and an arbitrary angle; an X-ray detection unit movably provided with an imaging unit including an image detection unit which generates an X-ray image by detecting X-rays transmitted through the object; a first calculation unit configured to calculate an irradiation field formed on said imaging unit by using a relative positional relationship between said generation unit and said imaging unit and an aperture value of said collimator; a second calculation unit configured to calculate the irradiation field formed on said imaging unit based on a dose of X-rays generated by said generation unit and an X-ray dose distribution detected by said image detection unit; and a decision unit configured to decide, as a predicted irradiation field, a region including one or both of irradiation fields respectively calculated by said first calculation unit and said second calculation unit, wherein an irradiation field formed on said imaging unit is controlled based on a predicted irradiation field decided by said decision unit.