X-ray CT apparatus with correction for object shift in response to movement of the scanning bed

Patent metadata

Field	Value
Publication number	US-9389190-B2
Application number	US-201414177824-A
Country	US
Kind code	B2
Filing date	Feb 11, 2014
Priority date	Sep 4, 2012
Publication date	Jul 12, 2016
Grant date	Jul 12, 2016

Abstract

An X-ray CT apparatus includes an X-ray tube, X-ray detector detecting the X-rays transmitted through an object, data acquisition unit acquiring projection data of the object based on an output from the X-ray detector, bed driving control unit moving a top to place the object along a long-axis direction of the top, image processing unit generating a reconstructed image based on the projection data, positional shift amount detection unit detecting a shift amount of a relative position between the top and the object, and positional shift processing unit performing processing based on a detection result obtained by the positional shift amount detection unit, in accordance with movement of the top by the bed driving control unit.

First claim

The invention claimed is:

1. An X-ray CT apparatus comprising:
an X-ray tube configured to generate X-rays;
an X-ray detector provided to face the X-ray tube and configured to detect the X-rays transmitted through an object;
a data acquisition unit configured to acquire projection data of the object based on an output from the X-ray detector;
a bed driving control unit configured to move a top to place the object along a long-axis direction of the top;
an image processing unit configured to generate a reconstructed image based on the projection data;
a positional shift amount detection unit configured to detect a shift amount of a position of the object relative to a position of the top, wherein the shift amount of the position of the object is due to the movement of the top along the long-axis by the bed driving control unit; and
a positional shift processing unit configured to perform processing based on a detection result obtained by the positional shift amount detection unit.

2. The X-ray CT apparatus of claim 1 , wherein the positional shift processing unit compares the shift amount of the position of the object relative to the position of the top with a predetermined threshold and, when detecting that the shift amount of the position of the object relative to the position of the top exceeds the predetermined threshold, controls the bed driving control unit to reduce at least one of a velocity and an acceleration concerning movement of the top by the bed driving control unit.

3. The X-ray CT apparatus of claim 2 , further comprising a system control unit configured to decide the predetermined threshold based on at least one of an imaging condition concerning the X-rays, a slice thickness of the reconstructed image, and a diagnosis target region in the object.

4. The X-ray CT apparatus of claim 1 , wherein the positional shift processing unit determines whether the shift amount of the position of the object relative to the position of the top exceeds a predetermined threshold, and notifies an operator of the X-ray CT apparatus of a determination result.

5. The X-ray CT apparatus of claim 1 , wherein the positional shift processing unit compares the shift amount of the position of the object relative to the position of the top with a predetermined threshold and, when detecting that the shift amount of the position of the object relative to the position of the top exceeds the predetermined threshold, notifies the operator of the X-ray CT apparatus so as to make the operator reduce at least one of a velocity and an acceleration concerning movement of the top by the bed driving control unit.

6. The X-ray CT apparatus of claim 1 , wherein the positional shift processing unit compares the shift amount of the position of the object relative to the position of the top with a predetermined threshold and, when detecting that the shift amount of the position of the object relative to the position of the top exceeds the predetermined threshold, controls the X-ray tube to delay an irradiation timing of the X-rays.

7. The X-ray CT apparatus of claim 6 , further comprising a system control unit configured to decide the predetermined threshold based on at least one of an imaging condition concerning the X-rays, a slice thickness of the reconstructed image, and a diagnosis target region in the object.

8. The X-ray CT apparatus of claim 1 , wherein the positional shift processing unit controls the image processing unit to perform reconstruction processing upon selecting the projection data to cancel the shift amount of the position of the object relative to the position of the top.

9. The X-ray CT apparatus of claim 1 , wherein
the image processing unit generates the reconstructed image by back projection computation, and
the positional shift processing unit controls the image processing unit to perform the back projection computation upon selecting a channel and a segment on the X-ray detector in accordance with the shift amount of the position of the object relative to the position of the top to cancel the shift amount of the position of the object relative to the position of the top for each position in a target for the back projection computation.

10. An X-ray CT apparatus comprising:
an X-ray tube configured to generate X-rays;
an X-ray detector provided to face the X-ray tube and configured to detect the X-rays transmitted through an object,
a data acquisition unit configured to acquire projection data of the object based on an output from the X-ray detector;
a bed driving control unit configured to move a top to place the object along a long-axis direction of the top;
an image processing unit configured to generate a reconstructed image based on the projection data; and
a control unit configured to control the X-ray tube to generate the X-rays, when a shift amount of a position of the object relative to a position of the top becomes smaller than a predetermined threshold, wherein the shift amount of the position of the object is due to the movement of the top along the long-axis by the bed driving control unit.

11. The X-ray CT apparatus of claim 10 , further comprising a system control unit configured to decide the predetermined threshold based on at least one of an imaging condition concerning the X-rays, a slice thickness of the reconstructed image, and a diagnosis target region in the object.

12. The X-ray CT apparatus of claim 1 , wherein
the bed driving control unit executes first reciprocating movement to reciprocatingly move the top on which the object is placed before scanning,
the positional shift amount detection unit detects the shift amount of the position of the object relative to the position of the top in the first reciprocating movement, and
the positional shift processing unit executes second reciprocating movement to reciprocatingly move the top, together with the scanning, upon reducing at least one of a velocity and an acceleration of the top in the first reciprocating movement, when the shift amount of the position of the object relative to the position of the top exceeds the predetermined threshold.

13. The X-ray CT apparatus of claim 12 , further comprising a system control unit configured to decide the predetermined threshold based on at least one of an imaging condition concerning the X-rays, a slice thickness of the reconstructed image, and a diagnosis target region in the object.

14. The X-ray CT apparatus of claim 1 , wherein
the bed driving control unit executes first reciprocating movement to reciprocatingly move the top on which the object is placed before scanning,
the positional shift amount detection unit detects the shift amount of the position of the object relative to the position of the top in the first reciprocating movement, and
the positional shift processing unit
executes second reciprocating movement to reciprocatingly move the top upon prolonging a stoppage period of the top in the first reciprocating movement when the shift amount of the position of the object relative to the position of the top exceeds the predetermined threshold, and
executes the scanning in a period during which the shift amount of the position of the object relative to the position of the top is not more than the predetermined threshold in the second reciprocating movement.

15. The X-ray CT apparatus of claim 14 , further comprising a system control unit configured to decide the predetermined threshold based on at least one of an imaging condition concerning the X-rays, a slice thickness of the reconstructed image, and a diagnosis target region in the object.

16. The

Assignees

• Toshiba Kk
• Toshiba Medical Sys Corp

Inventors

• Tsuyuki Masaharu

Classifications

• A61B6/03 Primary

  Computed tomography [CT] · CPC title

• A61B6/0407

  Supports, e.g. tables or beds, for the body or parts of the body · CPC title

• G01N23/046 Primary

  using tomography, e.g. computed tomography [CT] · CPC title

• A61B6/0457

  Human Necessities · mapped topic

• A61B6/0487

  Motor-assisted positioning · CPC title