X-ray CT method and X-ray CT apparatus

• US 20060291612A1
• Filed: 06/20/2006
• Published: 12/28/2006
• Est. Priority Date: 06/24/2005
• Status: Abandoned Application

• Current Assignee: GE Medical Systems Global Technology Company LLC (GE Healthcare Technologies, Inc.)
• Original Assignee: GE Medical Systems Global Technology Company LLC (GE Healthcare Technologies, Inc.)
• Inventors: Imai, Yasuhiro, Nishide, Akihiko
• Application Number:
  US11/471,124
• Publication Number:
  US 20060291612A1
• Time in Patent Office: Days
• US Class Current: 378/4
• CPC Class Codes: A61B 6/027 characterised by the use of a particular data acquisition trajectory, e.g. helical or spiral
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/4085 Cone-beams
• CPC Class Codes: A61B 6/469 for selecting a region of interest [ROI]
• CPC Class Codes: A61B 6/488 involving pre-scan acquisition

Abstract

In an X-ray CT apparatus, radiographic conditions (protocols) for imaging of each position represented by a z-coordinate are optimized in relation to an X-ray cone beam that spreads in a z direction. A slice thickness of a tomographic image is freely controlled in the z direction using a z filter during a conventional scan or a cine scan. For each tomographic image, a reconstruction function, an image filter, a scan field, a tomographic-image tilt angle, and a position of a tomographic image are freely adjusted or independently designated for scanning of each position in the z direction. Thus, a tomographic image is reconstructed. Moreover, the position of a beam formation X-ray filter in the z direction is shifted in order to optimize a patient dose that depends on the size of the scan field, and X-ray quality.

Claims

1. An X-ray CT method comprising the steps of:

rotating an X-ray generator and an X-ray area detector, which has a matrix structure and is opposed to the X-ray generator, about a center of rotation located between the X-ray generator and X-ray area detector so as to acquire X-ray projection data of a subject lying down near the center of rotation;

reconstructing an image by treating the acquired X-ray projection data;

displaying the reconstructed tomographic image; and

designating radiographic conditions for data acquisition, wherein;

a plurality of sets of radiographic conditions is designated for a conventional scan for which the X-ray generator and X-ray area detector make one rotation or a cine scan for which the position of the subject is held unchanged in a depth direction substantially orthogonal to a rotation plane on which the rotation is made; and

an image is reconstructed under the plurality of sets of radiographic conditions during the conventional scan or cine scan.

6. The X-ray CT method according to claim 1, wherein the X-ray area detector is a multi-array X-ray detector or a flat-panel X-ray detector.

7. The X-ray CT method according to claim 1, wherein the radiographic conditions include at least one of a slice thickness, a scan field, a reconstruction function, an image filter, a tomographic-image tilt angle, a position of a tomographic image, and an inter-tomographic image spacing.

8. The X-ray CT method according to claim 1, wherein the image reconstruction is three-dimensional image reconstruction.

2. An X-ray CT method comprising the steps of:

rotating an X-ray generator and an X-ray area detector, which has a matrix structure and is opposed to the X-ray generator, about a center of rotation located between the X-ray generator and X-ray area detector so as to acquire X-ray projection data of a subject lying down near the center of rotation;

reconstructing an image by treating the acquired X-ray projection data;

displaying the reconstructed tomographic image; and

designating radiographic conditions for data acquisition, wherein;

for data acquisition, an X-ray beam that is asymmetric to a direction orthogonal to a rotation plane on which the rotation is made is irradiated to the rotation plane;

a plurality of sets of radiographic conditions is designated for a conventional scan for which the X-ray generator and X-ray area detector make one rotation or a cine scan for which the position of the subject is fixed in a depth direction substantially orthogonal to the rotation plane on which the rotation is made; and

an image is reconstructed under the plurality of sets of radiographic conditions during the conventional scan or cine scan.

3. The X-ray CT method according to claim 2, wherein for data acquisition, a collimator disposed in front of an X-irradiation port of the X-ray generator is structured asymmetrically.

4. An X-ray CT method comprising the steps of:

rotating an X-ray generator and an X-ray area detector, which has a matrix structure and is opposed to the X-ray generator, about a center of rotation located between the X-ray generator and X-ray area detector so as to acquire X-ray projection data of a subject lying down near the center of rotation;

reconstructing an image by treating the acquired X-ray projection data;

displaying the reconstructed tomographic image; and

designating radiographic conditions for data acquisition, wherein;

prior to data acquisition, a rotation plane on which the rotation is made is tilted;

a plurality of sets of radiographic conditions is designated for a conventional scan for which the X-ray generator and X-ray area detector make one rotation or a cine scan for which the position of the subject is fixed in a depth direction substantially orthogonal to the rotation plane on which the rotation is made; and

an image is reconstructed under the plurality of sets of radiographic conditions during the conventional scan or cine scan.

5. An X-ray CT method comprising the steps of:

rotating an X-ray generator and an X-ray area detector, which has a matrix structure and is opposed to the X-ray generator, about a center of rotation located between the X-ray generator and X-ray area detector so as to acquire X-ray projection data of a subject lying down near the center of rotation;

reconstructing an image by treating the acquired X-ray projection data;

displaying the reconstructed tomographic image;

designating radiographic conditions for data acquisition; and

storing radiographic conditions recommended for each radiographic region of the subject, wherein;

for a conventional scan for which the X-ray generator and X-ray area detector make one rotation or a cine scan for which the position of the subject is fixed in a depth direction substantially orthogonal to a rotation plane on which the rotation is made, a radiographic region is delineated in a scout image of the subject, radiographic conditions recommended for the delineated radiographic region are retrieved, and a plurality of sets of radiographic conditions is designated based on the recommended radiographic conditions; and

an image is reconstructed under the plurality of sets of radiographic conditions during the conventional scan or cine scan.

9. An X-ray CT apparatus comprising:

an X-ray data acquisition device for rotating an X-ray generator and an X-ray area detector, which has a matrix structure and is opposed to the X-ray generator, about a center of rotation located between the X-ray generator and X-ray area detector so as to acquire X-ray projection data of a subject lying down near the center of rotation;

an image reconstruction device for reconstructing an image by treating the X-ray projection data acquired by the X-ray data acquisition device;

an image display device for displaying the reconstructed tomographic image; and

a radiographic condition designation device for use in designating radiographic conditions for data acquisition, wherein;

the radiographic condition designation device is used to designate a plurality of sets of radiographic conditions for a conventional scan for which the X-ray generator and X-ray area detector make one rotation or a cine scan for which the position of the subject is held unchanged in a z direction substantially orthogonal to a rotation plane on which the rotation is made; and

the image reconstruction device reconstructs an image under the plurality of sets of radiographic conditions during the conventional scan or cine scan.

14. The X-ray CT apparatus according to claim 9, wherein the X-ray area detector is a multi-array X-ray detector or a flat-panel X-ray detector.

15. The X-ray CT apparatus according to claim 9, wherein the radiographic conditions include at least one of a slice thickness, a scan field, a reconstruction function, an image filter, a tomographic-image tilt angle, a position of a tomographic image, and an inter-tomographic image spacing.

16. The X-ray CT apparatus according to claim 9, wherein the image reconstruction device includes a three-dimensional image reconstruction device.

10. An X-ray CT apparatus comprising:

an X-ray data acquisition device for rotating an X-ray generator and an X-ray area detector, which has a matrix structure and is opposed to the X-ray generator, about a center of rotation located between the X-ray generator and X-ray area detector so as to acquire X-ray projection data of a subject lying down near the center of rotation;

an image reconstruction device for reconstructing an image by treating the X-ray projection data acquired by the X-ray data acquisition device;

an image display device for displaying the reconstructed tomographic image; and

a radiographic condition designation device for use in designating radiographic conditions for data acquisition, wherein;

the X-ray data acquisition device irradiates an X-ray beam, which is asymmetric to a direction orthogonal to a rotation plane on which the rotation is made, to the rotation plane so as to acquire X-ray data;

the radiographic condition designation device is used to designate a plurality of sets of radiographic conditions for a conventional scan for which the X-ray generator and X-ray area detector make one rotation or a cine scan for which the position of the subject is fixed in a depth direction substantially orthogonal to the rotation plane on which the rotation is made; and

the image reconstruction device reconstructs an image under the plurality of sets of radiographic conditions during the conventional scan or cine scan.

11. The X-ray CT apparatus according to claim 10, wherein the X-ray data acquisition device includes a collimator that has an asymmetric structure and is disposed in front of an X-irradiation portion of the X-ray generator.

12. An X-ray CT apparatus comprising:

an X-ray data acquisition device for rotating an X-ray generator and an X-ray area detector, which has a matrix structure and is opposed to the X-ray generator, about a center of rotation located between the X-ray generator and X-ray area detector so as to acquire X-ray projection data of a subject lying down near the center of rotation;

an image reconstruction device for reconstructing an image by treating the X-ray projection data acquired by the X-ray data acquisition device;

an image display device for displaying the reconstructed tomographic image; and

a radiographic condition designation device for use in designating radiographic conditions for data acquisition, wherein;

the X-ray data acquisition device acquires data with a rotation plane, in which the rotation is made, tilted;

the radiographic condition designation device is used to designate a plurality of sets of radiographic conditions for a conventional scan for which the X-ray generator and X-ray area detector make one rotation or a cine scan for which the position of the subject is fixed in a depth direction substantially orthogonal to the rotation plane on which the rotation is made; and

the image reconstruction device reconstructs an image under the plurality of sets of radiographic conditions during the conventional scan or cine scan.

13. An X-ray CT apparatus comprising:

an X-ray data acquisition device for rotating an X-ray generator and an X-ray area detector, which has a matrix structure and is opposed to the X-ray generator, about a center of rotation located between the X-ray generator and X-ray area detector so as to acquire X-ray projection data of a subject lying down near the center of rotation;

an image reconstruction device for reconstructing an image by treating the X-ray projection data acquired by the X-ray data acquisition device;

an image display device for displaying the reconstructed tomographic image;

a radiographic condition designation device for use in designating radiographic conditions for data acquisition; and

a radiographic condition storage device in which radiographic conditions recommended for each radiographic region of the subject are stored, wherein;

for a conventional scan for which the X-ray generator and X-ray area detector make one rotation or a cine scan for which the position of the subject is fixed in a depth direction substantially orthogonal to a rotation plane on which the rotation is made, the radiographic condition designation device is used to delineate a radiographic region in a scout image of the subject, retrieve radiographic conditions recommended for the delineated radiographic region, and designate a plurality of sets of radiographic conditions according to the recommended radiographic conditions; and

the image reconstruction device reconstructs an image under the plurality of sets of radiographic conditions during the conventional scan or cine scan.