X-ray image apparatus having calculating means for calculating the observing area in the subject

An X-ray image apparatus, comprising:

• X-ray irradiation means for irradiating X-ray to a subject with an observing area,
• X-ray image taking means for receiving the X-ray irradiated from the X-ray irradiation means and passing through the subject, said X-ray image taking means providing image signals by the X-ray passing through the subject,
• support means connected to the X-ray irradiation means and the X-ray image taking means, said supporting means supporting and moving both means around the subject,
• calculating means electrically connected to the X-ray image taking means for calculating a location of the observing area in the subject by image signals obtained from at least two different directions, said calculating means, in setting the observing area, receiving at least two images of the subject with the observing area different in directions without setting a center of rotation of the support means for the observing area, and calculating the location of the observing area with respect to the center of the rotation, said center being located in a middle of a line connecting between the X-ray irradiation means and the X-ray image taking means, and
• control means electrically connected to the calculating means for controlling a relative position of the support means with respect to the subject, said control means, upon receiving the location of the observing area with respect to the center of rotation, moving the support means to accord the center of rotation of the support means with the observing area in the subject.