Image generating apparatus, radiation tomography imaging apparatus, and image generating method and program

• US 10,134,157 B2
• Filed: 12/15/2014
• Issued: 11/20/2018
• Est. Priority Date: 02/27/2014
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Hagiwara, Akira
• Primary Examiner(s): Wu, Jingge
• Application Number:
  US15/121,332
• Publication Number:
  US 20170084059A1
• Time in Patent Office: 1,436 Days
• CPC Class Codes: G06T 11/008 Specific post-processing after tomographic reconstruction, e.g. voxelisation, metal artifact correction
• CPC Class Codes: G06T 2207/10081 Computed x-ray tomography [CT]

Abstract

[Problem] To further reduce artifacts of a reconstructed image. [Solution] Provided is an image generating apparatus which includes: a determining unit configured to determine projection data collected by scan of an imaging object using a radiation source and a detector; a first setting unit configured to set a plurality of first reconstruction planes corresponding to images to be supplied to an operator, in the body axis direction of the imaging object; a second setting unit configured to set one or more second reconstruction planes corresponding to one or more images not to be supplied to the operator and different from the first reconstruction planes, in the body axis direction; a reconstruction unit configured to reconstruct a plurality of images corresponding to the plural first reconstruction planes and images corresponding to the one or more second reconstruction planes, based on the projection data; and a processing unit configured to perform an artifact reduction process on an image corresponding to a given first reconstruction plane using a plurality of images corresponding to a plurality of reconstruction planes including the plural first reconstruction planes and at least one of the one or more second reconstruction planes.

Claims

1. An image generating apparatus comprising:

a determiner configured to determine projection data collected by a scan of an imaging object using a radiation source and a detector;

a first setter configured to set a plurality of first reconstruction planes in a body axis direction of the imaging object;

a second setter configured to set one or more second reconstruction planes different from the plurality of first reconstruction planes in the body axis direction of the imaging object, wherein the plurality of first reconstruction planes are located at different locations along the body axis direction from the one or more second reconstruction planes;

a reconstructor configured to reconstruct a plurality of images corresponding to the plurality of first reconstruction planes and to be supplied to an operator and one or more images corresponding to the one or more second reconstruction planes, based on the projection data; and

a processor configured to perform an artifact reduction process on an image corresponding to a given first reconstruction plane using a plurality of images corresponding to a plurality of reconstruction planes including the plurality of first reconstruction planes and at least one of the one or more second reconstruction planes,

wherein the processor is further configured to;

calculate a probability that a pixel in the image corresponding to the given first reconstruction plane represents an artifact based on pixel value variations in the plurality of images corresponding to the plurality of reconstruction planes, the pixel value variations are variations in the body axis direction; and

perform the artifact reductions process on the pixel based on the probability.

2. The image generating apparatus according to claim 1, wherein the second setter sets one or more second reconstruction planes in a given range including the given first reconstruction plane and one or more other first reconstruction planes near the given first reconstruction plane, and

wherein the processor performs the artifact reduction process using a plurality of images corresponding to the plural reconstruction planes included in the given range.

3. The image generating apparatus according to claim 2, wherein the given range is a range which includes the given first reconstruction plane and two first reconstruction planes on both adjacent sides thereof, and

wherein the second setter sets one or more second reconstruction planes between the given first reconstruction plane and each of the two first reconstruction planes on the both adjacent sides thereof.

4. The image generating apparatus according to claim 1, wherein the second setter sets one second reconstruction plane at every middle position between two first reconstruction planes adjacent to each other.

5. The image generating apparatus according to claim 1, wherein the first setter sets the plurality of first reconstruction planes based on conditions of an imaging range and slice thickness which are specified by the operator.

6. The image generating apparatus according to claim 1, wherein distance between the given first reconstruction plane and a second reconstruction plane nearest to the given first reconstruction plane is smaller than minimum slice thickness that the operator can set.

7. The image generating apparatus according to claim 1, wherein the processor performs the artifact reduction process on a basis of pixels constituting an image corresponding to the given first reconstruction plane.

8. The image generating apparatus according to claim 7, wherein the processor calculates probability that a given pixel in the image corresponding to the given first reconstruction plane represents an artifact, using images corresponding to first and second reconstruction planes included in the given range, and controls a parameter for the artifact reduction process on the pixel according to the probability.

9. The image generating apparatus according to claim 1, wherein the reconstructor reconstructs the images by a three-dimensional back projection process on the projection data.

10. The image generating apparatus according to claim 1, wherein the artifact reduction process includes a filtering process.

11. The image generating apparatus according to claim 10, wherein the filtering process includes a weighted addition process of the plurality of images.

12. The image generating apparatus according to claim 1, wherein the scan is helical scan.

13. The image generating apparatus according to claim 1, further comprising a display controller configured to control a display so as to display images corresponding to the plurality of first reconstruction planes but not to display images corresponding to the second reconstruction planes.

17. The image generating apparatus according to claim 1, wherein the artifact reduction process comprises a filtering process, the filtering process comprises a weighted addition process of the plurality of images, and the processor is configured to control a weighting factor of the weighted addition process based on the probability.

14. A radiation tomography imaging apparatus comprising:

a scanner configured to collect projection data by scanning an imaging object using a radiation source and a detector,

a first setter configured to set a plurality of first reconstruction planes in a body axis direction of the imaging object;

a second setter configured to set one or more second reconstruction planes different from the plurality of first reconstruction planes in the body axis direction of the imaging object, wherein the plurality of first reconstruction planes are located at different locations along the body axis direction from the one or more second reconstruction planes;

a reconstructor configured to reconstruct a plurality of images corresponding to the plurality of first reconstruction planes and to be supplied to an operator and one or more images corresponding to the one or more second reconstruction planes, based on the projection data; and

a processor configured to perform an artifact reduction process on an image corresponding to a given first reconstruction plane using at least some of the images corresponding to the plurality of first reconstruction planes and at least some of the images corresponding to the one or more second reconstruction planes,

wherein the processor is further configured to calculate a probability that a pixel in the image corresponding to the given first reconstruction plane represents an artifact based on pixel value variations in the images corresponding to the plurality of first reconstruction planes and the images corresponding to the one or more second reconstruction planes, the pixel value variations are variations in the body axis direction; and

perform the artifact reduction process on the pixel based on the probability.

15. An image generating method comprising:

determining projection data collected by a scan of an imaging object using a radiation source and a detector;

setting a plurality of first reconstruction planes in a body axis direction of the imaging object;

setting one or more second reconstruction planes different from the plurality of first reconstruction planes in the body axis direction of the imaging object, wherein the plurality of first reconstruction planes are located at different locations along the body axis direction from the one or more second reconstruction planes;

reconstructing a plurality of images corresponding to the plurality of first reconstruction planes and to be supplied to an operator and one or more images corresponding to the one or more second reconstruction planes, based on the projection data; and

performing an artifact reduction process on an image corresponding to a given first reconstruction plane using at least some of the images corresponding to the plurality of first reconstruction planes and at least some of the images corresponding to the one or more second reconstruction planes,

wherein performing the artifact reduction process on the image comprises;

calculating a probability that a pixel in the image corresponding to the given first reconstruction plane represents an artifact based on pixel value variations in the images corresponding to the plurality of first reconstruction planes and the images corresponding to the one or more second reconstruction planes, the pixel value variations are variations in the body axis direction; and

performing the artifact reduction process on the pixel based on the probability.

16. One or more non-transitory computer-readable media encoding executable routines, wherein the routines, when executed by a processor, cause acts to be performed comprising:

determining projection data collected by a scan of an imaging object using a radiation source and a detector;

setting a plurality of first reconstruction planes in a body axis direction of the imaging object;

setting one or more second reconstruction planes different from the plurality of first reconstruction planes in the body axis direction of the imaging object, wherein the plurality of first reconstruction planes are located at different locations along the body axis direction from the one or more second reconstruction planes;

reconstructing a plurality of images corresponding to the plurality of first reconstruction planes and to be supplied to an operator and one or more images corresponding to the one or more second reconstruction planes, based on the projection data; and

performing an artifact reduction process on an image corresponding to a given first reconstruction plane using at least some of the images corresponding to the plurality of first reconstruction planes and at least some of the images corresponding to the one or more second reconstruction planes,

wherein performing the artifact reduction process on the image further comprises;

calculating a probability that a pixel in an image corresponding to the given first reconstruction plane represents an artifact based on pixel value variations in the one or more images corresponding to the plurality of reconstruction planes, the pixel value variations are variations in the body axis direction; and

performing the artifact reduction process on the pixel based on the probability.