Method for reducing motion induced image artifacts in projection imaging

Claim 1

A method for reducing image artifacts resulting from periodic motion of an object, where the image is produced from a set of projections taken along a plurality of projection axes about the object, said method comprising: producing a signal indicative of said periodic motion; producing a series of reference signals which indicate a pre-established point in each of a series of said periodic motions; identifying a quiescent period related to the pre-­established point in each reference signal; starting the acquisition of projections at a time related to the reference signal so that the total acquisition time for one projection set is centered in the quiescent period.

Claim 2

A method for reducing image artifacts resulting from periodic motion of an object, where the image is produced from a set of projections taken along a plurality of projection axes about the object, said method comprising: producing a signal indicative of said periodic motion; producing a series of reference signals which indicate a pre-established point in each of a series of said periodic motions; identifying a quiescent period related to the pre-­established point in each reference signal; starting the acquisition of projections at a time related to the reference signal so that the total acquisition time for one projection set is centered in the quiescent period.

Claim 3

A method for reducing image artifacts resulting from periodic motion of an object, where the image is produced from a set of projections taken along a plurality of projection axes about the object, said method comprising: identifying a principal axis of the periodic motion; controlling the sequence of projection axes so that the range of projection axes is centered on an angle perpendicular to the principal.axis of the periodic motion.

Claim 4

A method for reducing image artifacts resulting from periodic motion of an object, where the image is produced from a set of projections taken along a plurality of projection axes about the object, said method comprising: identifying a principal axis of the periodic motion; controlling the sequence of projection axes so that the range of projection axes is centered on an angle perpendicular to the principal.axis of the periodic motion.

Claim 7

A method for reducing image artifacts resulting from a primary periodic motion and at least one secondary periodic motion of an object, where the image is produced from a set of projections taken along a plurality of projection axes about the object, said method comprising: producing a signal indicative of each said periodic motion; producing a series of reference signals for each said periodic motion which indicate pre-established points in each cycle of said periodic motions; identifying centerpoints in quiescent periods related to the pre-established points in each reference signal; examining a predetermined time interval of the primary periodic motion to identify a quiescent period, related to the reference signal for the primary periodic motion, in which the centerpoints among the primary and secondary periodic motions are closest; starting the acquisition of projections at a time related to the primary periodic motion′s reference signal so that the total acquisition time for one projection set is centered in the identified quiescent period.

Claim 8

A method for reducing image artifacts resulting from a primary periodic motion and at least one secondary periodic motion of an object, where the image is produced from a set of projections taken along a plurality of projection axes about the object, said method comprising: producing a signal indicative of each said periodic motion; producing a series of reference signals for each said periodic motion which indicate pre-established points in each cycle of said periodic motions; identifying centerpoints in quiescent periods related to the pre-established points in each reference signal; examining a predetermined time interval of the primary periodic motion to identify a quiescent period, related to the reference signal for the primary periodic motion, in which the centerpoints among the primary and secondary periodic motions are closest; starting the acquisition of projections at a time related to the primary periodic motion′s reference signal so that the total acquisition time for one projection set is centered in the identified quiescent period.

Claim 10

An apparatus for producing tomographic images of objects with periodic motion, where each image is reconstructed from a set of projections acquired from detectors on a rotating gantry, the apparatus comprising: a transducer producing a signal indicative of said periodic motion; a detector producing a series of reference signals which indicate a preestablished point in each of a series of said periodic motions; a computer means for identifying a quiescent period related to the pre-established point in each reference signal,; a gantry controller means for starting the acquisition of projections at a time related to the reference signal so that the total acquisition time for one projection set is centered in the quiescent period.

Claim 11

An apparatus for producing tomographic images of objects with periodic motion, where each image is reconstructed from a set of projections acquired from detectors on a rotating gantry, the apparatus comprising: a transducer producing a signal indicative of said periodic motion; a detector producing a series of reference signals which indicate a preestablished point in each of a series of said periodic motions; a computer means for identifying a quiescent period related to the pre-established point in each reference signal,; a gantry controller means for starting the acquisition of projections at a time related to the reference signal so that the total acquisition time for one projection set is centered in the quiescent period.

Claim 12

A method for reducing image artifacts resulting from periodic motion of an object, where the image is produced from a set of projections taken along a plurality of projection axes about the object, said method comprising: producing a signal indicative of said periodic motion; producing a series of reference signals which indicate a pre- established point in each of a series of said periodic motions; identifying a quiescent period related to the pre-­established point in each reference signal; starting the acquisition of projections at a time related to the reference signal so as to acquire projections both during the quiescent period and outside of the quiescent period; selecting a set of projections from the acquired projections where such projection set is centered in the quiescent period.

Claim 13

A method for reducing image artifacts resulting from periodic motion of an object, where the image is produced from a set of projections taken along a plurality of projection axes about the object, said method comprising: producing a signal indicative of said periodic motion; producing a series of reference signals which indicate a pre- established point in each of a series of said periodic motions; identifying a quiescent period related to the pre-­established point in each reference signal; starting the acquisition of projections at a time related to the reference signal so as to acquire projections both during the quiescent period and outside of the quiescent period; selecting a set of projections from the acquired projections where such projection set is centered in the quiescent period.

Claim 14

An apparatus for reducing image artifacts resulting from periodic motion of an object, where the image is produced from a set of projections taken along a plurality of projection axes about the object, comprising: means for producing a signal indicative of said periodic motion; means for producing a series of reference signals which indicate a pre-established point in each of a series of said periodic motions; means for identifying a quiescent period related to the pre-­established point in each reference signal; means for starting the acquisition of projections at a time related to the reference signal so that the total acquisition time for one projection set is centered in the quiescent period.

Claim 15

An apparatus for reducing image artifacts resulting from periodic motion of an object, where the image is produced from a set of projections taken along a plurality of projection axes about the object, comprising: means for producing a signal indicative of said periodic motion; means for producing a series of reference signals which indicate a pre-established point in each of a series of said periodic motions; means for identifying a quiescent period related to the pre-­established point in each reference signal; means for starting the acquisition of projections at a time related to the reference signal so that the total acquisition time for one projection set is centered in the quiescent period.

Claim 16

An apparatus for reducing image artifacts resulting from periodic motion of an object, where the image is produced from a set of projections taken along a plurality of projection axes about the object, comprising: means for identifying a principal axis of the periodic motion; means for controlling the sequence of projection axes so that the range of projection axes is centered on an angle perpendicular to the principal axis of the periodic motion.

Claim 17

An apparatus for reducing image artifacts resulting from periodic motion of an object, where the image is produced from a set of projections taken along a plurality of projection axes about the object, comprising: means for identifying a principal axis of the periodic motion; means for controlling the sequence of projection axes so that the range of projection axes is centered on an angle perpendicular to the principal axis of the periodic motion.

Claim 20

An apparatus for reducing image artifacts resulting from a primary periodic motion and at least one secondary periodic motion of an object, where the image is produced from a set of projections taken along a plurality of projection axes about the object, comprising: means for producing a signal indicative of each said periodic motion; means for producing a series of reference signals for each said periodic motion which indicate pre-established points in each cycle of said periodic motions; means for identifying centerpoints in quiescent periods related to the pre-established points in each reference signal; means for examining a predetermined time interval of the primary periodic motion to identify a quiescent period, related to the reference signal for the primary periodic motion, in which the centerpoints among the primary and secondary periodic motions are closest; means for starting the acquisition of projections at a time related to the primary periodic motion's reference signal so that the total acquisition time for one projection set is centered in the identified quiescent period.

Claim 21

An apparatus for reducing image artifacts resulting from a primary periodic motion and at least one secondary periodic motion of an object, where the image is produced from a set of projections taken along a plurality of projection axes about the object, comprising: means for producing a signal indicative of each said periodic motion; means for producing a series of reference signals for each said periodic motion which indicate pre-established points in each cycle of said periodic motions; means for identifying centerpoints in quiescent periods related to the pre-established points in each reference signal; means for examining a predetermined time interval of the primary periodic motion to identify a quiescent period, related to the reference signal for the primary periodic motion, in which the centerpoints among the primary and secondary periodic motions are closest; means for starting the acquisition of projections at a time related to the primary periodic motion's reference signal so that the total acquisition time for one projection set is centered in the identified quiescent period.

Claim 22

The apparatus described in claim l3 including the additional means for identifying a principal axis of the periodic motion; controlling the sequence of projection axes so that the range of projection axes are centered on an angle perpendicular to the principal axis of the periodic motion.