X-ray diagnostic apparatus and medical image processing method

Patent metadata

Field	Value
Publication number	US-2016148398-A1
Application number	US-201414553716-A
Country	US
Kind code	A1
Filing date	Nov 25, 2014
Priority date	Nov 25, 2014
Publication date	May 26, 2016
Grant date	—

Abstract

An X ray diagnostic apparatus includes an X ray tube generating X rays, a first detector detecting the X rays, at least one second detector arranged in front of a first detection surface of the first detector and including a second detection surface narrower than the first detection surface and indicator points provided on a rear surface of the second detection surface, a projection data generation unit generating first projection data based on an output from the first detector, and a positional shift detection unit detecting a positional shift of the second detector relative to the first detector in accordance with an imaging direction by using the first projection data and a predetermined positional relationship between the points and detection elements in the second detector.

First claim

1 . An X-ray diagnostic apparatus comprising:
an X-ray tube configured to generate X-rays; a first detector configured to detect the X-rays; at least one second detector arranged in front of a first detection surface of the first detector and including a second detection surface narrower than the first detection surface and a plurality of indicator points provided on a rear surface of the second detection surface; a projection data generation unit configured to generate first projection data based on an output from the first detector; and a positional shift detection unit configured to detect a positional shift of the second detector relative to the first detector in accordance with an imaging direction by using the first projection data and a predetermined positional relationship between the indicator points and a plurality of detection elements in the second detector.

2 . The apparatus according to claim 1 , wherein the projection data generation unit is configured to generate the first projection data in association with rotational imaging of performing imaging while rotating, along a predetermined orbit around a predetermined rotation axis, the X-ray tube, the first detector, and the second detector, and to generate second projection data based on an output from the second detector in association with the rotational imaging with respect to an object, and
the apparatus further comprises a positional shift correction unit configured to correct the positional shift of the second projection data by using the imaging direction in the rotational imaging and the positional shift, and a reconstruction unit configured to reconstruct volume data based on the corrected second projection data.

3 . The apparatus according to claim 2 , further comprising a storage unit configured to store a first correspondence table used for orbit correction of correcting an orbit shift of the first detector relative to the orbit in accordance with the imaging direction,
wherein the positional shift correction unit is configured to generate a second correspondence table used for correction of the positional shift with respect to the imaging direction, and to correct the second projection data by using the first correspondence table and the second correspondence table.

4 . The apparatus according to claim 3 , wherein the positional shift detection unit is configured to detect the positional shift before the rotational imaging with respect to the object, and
the positional shift correction unit is configured to generate the second correspondence table before the rotational imaging with respect to the object.

5 . The apparatus according to claim 3 , wherein the positional shift detection unit is configured to detect the positional shift during the rotational imaging, and
the positional shift correction unit is configured to generate the second correspondence table based on the detected positional shift.

6 . The apparatus according to claim 3 , wherein the second projection data is projection data obtained in a predetermined imaging direction different from the imaging direction in the second correspondence table,
the positional shift correction unit is configured to interpolate a positional shift corresponding to the predetermined imaging direction by using two imaging directions adjacent to the predetermined imaging direction, the predetermined imaging direction, and the two positional shifts respectively corresponding to the two imaging directions in the second correspondence table, and to correct the second projection data by using the interpolated positional shift, and the reconstruction unit is configured to reconstruct volume data based on the corrected second projection data.

7 . The apparatus according to claim 2 , wherein the rotational imaging is executed while maintaining a field of view covering a region which covers a detection surface of the second detector and is narrower than a detection surface of the first detector.

8 . The apparatus according to claim 1 , wherein the projection data generation unit is configured to generate the first projection data in association with rotational imaging of imaging an object while rotating, along a predetermined orbit around a predetermined rotation axis, the X-ray tube, the first detector, and the second detector, and to generate second projection data based on an output from the second detector, and
the apparatus further comprises a positional shift correction unit configured to correct the second projection data by using the positional shift and the imaging direction in the rotational imaging, and a reconstruction unit configured to reconstruct volume data based on the corrected second projection data.

9 . The apparatus according to claim 1 , further comprising an image generation unit configured to generate an indicator point image including the indicator points based on the first projection data,
wherein the positional shift detection unit is configured to detect the indicator points on the indicator point image and to detect the positional shift by using the detected indicator points and the predetermined positional relationship.

10 . The apparatus according to claim 9 , wherein the indicator points are markers mounted on the second detector or structures forming the second detector, and
the indicator points has a characteristic pattern including a transmitting region and a non-transmitting region with respect to the X-rays.

11 . The apparatus according to claim 10 , wherein a rear surface side of the indicator points is configured to transmit the X-rays.

12 . The apparatus according to claim 9 , wherein the positional shift detection unit is configured to detect the positional shift by executing template matching or cross-correlation with respect to the indicator point image and a predetermined template image.

13 . The apparatus according to claim 1 , further comprising a counterweight configured to compensate for a difference in a barycentric position of the second detector between a first state in which the second detector is retracted from an X-ray irradiation range associated with the first detector and a second state in which the second detector is arranged in front of the first detector, and
a support mechanism configured to movably support the counterweight and the second detector.

14 . The apparatus according to claim 13 , wherein the counterweight has a point-like shape, and
the support mechanism is configured to support the counterweight so as to make the counterweight movable in a direction opposite to a moving direction of the second detector between the first state and the second state and so as to locate the counterweight on one side or two sides of the first detector.

15 . The apparatus according to claim 13 , wherein the counterweight has a rod-like shape, and
the support mechanism is configured to support the counterweight so as to make the counterweight movable in a direction opposite to a moving direction of the second detector between the first state and the second state and so as to surround the first detector.

16 . The apparatus according to claim 1 , further comprising a positional shift correction unit configured to correct a position of a collimator configured to limit an X-ray irradiation range or a positional shift of a compensation filter configured to attenuate a dose of the X-rays in accordance with the imaging direction.

17 . The apparatus according to claim 1 , further comprising a positional shift correction unit configured to correct a positional shift in a projection di

Assignees

• Toshiba Medical Sys Corp
• Univ At Buffalo The State University Of New York

Inventors

• Takemoto Hisato
• Jain Amit
• Sakaguchi Takuya
• Rudin Stephen
• Bednarek Daniel
• Ionita Ciprian

Classifications

• G06T12/10 Primary

  Image preprocessing, e.g. calibration, positioning of sources or scatter correction · CPC title

• A61B6/5276

  involving measuring table sag · CPC title

• A61B6/5235

  combining images from the same or different ionising radiation imaging techniques, e.g. PET and CT · CPC title

• A61B6/5247

  combining images from an ionising-radiation diagnostic technique and a non-ionising radiation diagnostic technique, e.g. X-ray and ultrasound · CPC title

• A61B6/4266

  characterised by using a plurality of detector units (A61B6/4014 takes precedence) · CPC title