X-ray imaging method and apparatus to reduce X-ray exposure of subject regions other than the diagnostically relevant subject region

An x-ray imaging apparatus comprising;

• an x-ray source with a focus from which an x-ray beam is emitted into a measurement volume comprising a central axis;
• a support configured to support an examination subject in said measurement volume, said examination subject comprising a measurement object, of which an image is to be obtained, that is located eccentrically relative to said central axis;
• a processor provided with an overview image of said examination subject in said measurement volume, said processor being configured to automatically identify a portion of the measurement volume in which said measurement object is located;
• said processor being configured to determine, dependent on the identified portion of the measurement volume in which the measurement object is located, a projection angle range to which acquisition of only a number of x-ray projections will be confined, with said number of x-ray projections being sufficient to reconstruct at least one image of the measurement object;
• a control unit configured to operate said x-ray source to rotate at least said focus of said x-ray source around said measurement volume through said projection angle range to acquire said number of x-ray projections of said measurement object;
• and
• a computer configured to reconstruct said at least one image of the measurement object from said number of x-ray projections.

A non-transitory, computer-readable data storage medium encoded with programming instructions, said storage medium being loaded into a computerized control and processing system of an imaging apparatus that comprises an x-ray source having a focus from which an x-ray beam is emitted into a measurement volume comprising a central axis, with an examination subject being located in said measurement volume, said examination subject comprising a measurement object, of which an image is to be obtained, located eccentrically relative to said central axis of said measurement volume, said programming instructions causing said computerized control and evaluation system to:

• use an overview image of said examination subject in said measurement volume to automatically identify a portion of the measurement volume in which said measurement object is located;
• dependent on the identified portion of the measurement volume in which the measurement object is located, determine a projection angle range to which acquisition of only a number of x-ray projections will be confined and in which said number of x-ray projections is sufficient to reconstruct at least one image of the measurement object;
• operate said x-ray source to rotate at least said focus of said x-ray source around said measurement volume through said projection angle range to acquire said number of x-ray projections of said measurement object;
• and
• reconstruct said at least one image of the measurement object from said number of x-ray projections.