Method for subjecting PET image to motion compensation and attenuation correction by using small number of low-radiation-dose CT images

Patent metadata

Field	Value
Publication number	US-9582906-B2
Application number	US-201214421769-A
Country	US
Kind code	B2
Filing date	Dec 14, 2012
Priority date	Oct 29, 2012
Publication date	Feb 28, 2017
Grant date	Feb 28, 2017

Abstract

The present invention relates to a method for motion compensation and state-of-motion specific attenuation correction of positron tomography images by using a small number of low-radiation-dose computer tomography images. The method of the present invention comprises the steps of: acquiring respiration-specific PET data; acquiring CT images from at least 2 different respirations, and using same to generate a virtual 4D CT image; matching the 4D CT image and the respiration-specific PET data, and selecting 3D CT images accurately corresponding to specific respirations; using the selected results to extract respiration motion displacement field information between respiration-specific PET data; using the selected CT images to subject the respiration-specific PET data to respiration-specific attenuation and scattering correction; and using the corrected respiration-specific PET data items and the extracted respiration motion displacement field information items to carry out respiration compensation and reconstruction.

First claim

What is claimed is:

1. A method for constructing a positron emission tomography (PET) image, comprising:
acquiring phase-matched PET data;
acquiring CT images corresponding to at least two different respiratory states and generating a virtual 4D CT image using the acquired CT images;
selecting 3D CT images, corresponding to the phase-matched PET data, from among the 4D CT images; and
performing phase-matched attenuation correction and phase-matched scattering correction on the phase-matched PET data using the selected 3D CT images.

2. The method of claim 1 , further comprising:
performing respiratory motion compensation and reconstruction on the phase-matched PET data, suffering the attenuation correction and the scattering correction, using a selected 3D CT image corresponding to each respiration.

3. The method of claim 2 , wherein respiratory motion information among phase-matched PET data is estimated by matching the virtual 4D CT image and a phase-matched PET image using a distortion phenomenon of the attenuation correction.

4. The method of claim 1 , wherein each of the CT images acquired at the different respiratory states is obtained and utilized using about 10˜50% of a radiation doze that is used when scanning one discrete CT image.

5. The method of claim 1 , wherein different respirations corresponding to the at least two different respiratory states include inhalation and exhalation or inhalation, exhalation and an intermediate respiration.

6. The method of claim 1 , wherein the phase-matched PET data is acquired in a list-mode PET data acquisition mode, with a respiratory gating system mounted on a patient's chest or abdomen.

7. The method of claim 1 , wherein the generating of a virtual 4D CT image comprises:
dividing the CT images of different respirations into regions according to a motion characteristic;
performing image registration every region;
merging the image-registered regions.

8. The method of claim 7 , wherein the performing of image registration every region is made using B-spline FFD (Free Form Deformation) conversion.

9. The method of claim 8 , wherein motion characteristic information of each region is applied to the B-spline FFD conversion as a constraint.

10. The method of claim 7 , wherein the merging of the image-registered regions comprises:
performing refinement on a respiratory region motion field at a boundary.

11. The method of claim 10 , wherein the refinement is performed using a graph-cut algorithm.

12. The method of claim 1 , wherein the performing of phase-matched attenuation correction and phase-matched scattering correction comprises:
matching CT images, corresponding to the phase-matched PET data, from among the 4D CT images.

13. The method of claim 12 , wherein the matched CT images are selected by performing attenuation correction and reconstruction on the phase-matched PET image and searching for a CT image corresponding to phase-matched PET data using a distortion degree of the attenuation correction measured from the reconstructed image.

14. The method of claim 12 , wherein a CT image corresponding to phase-matched PET data is selected using the distortion degree of the attenuation correction independently every phase-matched PET data.

15. The method of claim 12 , wherein a CT image corresponding to phase-matched PET data is selected using the distortion degree of the attenuation correction such that a sum of a whole distortion degree of the attenuation correction and a respiratory motion error degree is minimized, under the condition that phase-matched PET data is used as a whole set.

Assignees

• Korea Advanced Inst Sci & Tech

Inventors

• Ra Jong-Beom
• Nam Woo-Hyun
• Ahn Il-Jun
• Kim Ji-Hye
• Jang Yong-Jin
• Park Young-Zoon

Classifications

• G06T12/10 Primary

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

• G06T11/005 Primary

  Physics · mapped topic

• G06T2211/416

  Exact reconstruction · CPC title

• A61B6/00 Primary

  Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment (instruments measuring radiation intensity for application in the field of nuclear medicine, e.g. in vivo counting, G01T1/161) · CPC title

• A61B6/03

  Computed tomography [CT] · CPC title