Patent ID: 8155269

Claim:
An X-ray imaging apparatus comprising: an X-ray generation unit configured to irradiate an object with X-rays in a rectangular shape; and configured to emit a plurality of visible light beams including a visible light beam that matches with an X-ray reference axis, a set of two visible light beams that define a first plane including the X-ray reference axis,and a visible light beam that travels on a second plane without matching with the X-ray reference axis; an imaging unit which has a rectangular imaging plane and is configured to receive the X-rays transmitted through the object as an X-ray image, wherein the rectangular imaging plane has a center index at its center thereof where a first reference axis and a second reference axis perpendicular to the first reference axis intersect with each other, and the rectangular imaging plane includes a plurality of distance indexes on the first reference axis and the second reference axis each distance index representing a predetermined distance between the X-ray generation unit and the imaging unit, and wherein the imaging unit is arranged on an imaging plane which is spaced at each of the predetermined distances represented by the plurality of distance indexes apart from the X-ray generation unit and perpendicular to the X-ray reference axis such that a center of an irradiation field and a center of the imaging plane match with each other and rotational angles of the irradiation field and the imaging plane around the X-ray reference axis match with each other, by matching the plurality of visible light beams with the plurality of distance indexes provided in the imaging unit.