Intergrated single photon emission computed tomography (SPECT)/transmission computed tomography (TCT) system for cardiac imaging

• US 20080137806A1
• Filed: 12/07/2007
• Published: 06/12/2008
• Est. Priority Date: 12/08/2006
• Status: Active Grant

• Current Assignee: Rush University Medical Center (Rush University)
• Original Assignee: Rush University Medical Center (Rush University)
• Inventors: Chang, Wei
• Granted Patent: US 7,683,332 B2
• Time in Patent Office: Days
• US Class Current: 378/17
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/037 Emission tomography

Abstract

This invention features an integrated single photon emission computed tomography (SPECT)/transmission computed tomography (TCT) system for cardiac imaging including an open arc-shaped frame. A collimator system is shaped to approximately match the thoracic contour of patients having different sizes and weights and shaped to surround and position the collimator closely proximate a heart of a patient of said patients encompassed by at least one predetermined image volume for optimizing collimation of radiation photons emitted from the heart. An arc-shaped detector system is coupled to the collimator subsystem having a shape closely matching the shape of the collimator subsystem for detecting collimated radiation photons from the collimator subsystem and generating output electrical signals. A patient positioning subsystem positions a patient to a predetermined central longitudinal axis of the three-dimensional imaging volume and for intermittently and incrementally rotating the patient about the predetermined central longitudinal axis for generating a plurality of TCT images.

Claims

1. An integrated single photon emission computed tomography (SPECT)/transmission computed tomography (TCT) system for cardiac imaging comprising:

an open arc-shaped frame;

a collimator system shaped to approximately match the thoracic contour of patients having different sizes and weights and shaped to surround and position the collimator closely proximate a heart of a patient of said patients encompassed by at least one predetermined image volume for optimizing collimation of radiation photons emitted from the heart;

an arc-shaped detector system coupled to the collimator subsystem having a shape closely matching the shape of the collimator subsystem for detecting collimated radiation photons from the collimator subsystem and generating output electrical signals; and

a patient positioning subsystem for positioning a patient to a predetermined central longitudinal axis of the three-dimensional imaging volume and for intermittently and incrementally rotating the patient about the predetermined central longitudinal axis for generating a plurality of TCT images.

2. The system of claim 1 in which the shape of the collimator subsystem and the detector subsystems optimize collimation and detection of the radiation photons for a majority of the patients of a patient population.

3. The system of claim 1 in which the predetermined imaging volume includes a three-dimensional cylindrical imaging volume.

4. The system of claim 1 in which the arc-shaped frame, the collimator system, and the detector subsystem are subtended at an angle in the range of about 180°

to 220°

with respect to the center of the predetermined imaging volume.

5. The system of claim 1 in which the collimator subsystem includes a slit-plate comprising a predetermined number of spaced longitudinal slits each having a predetermined width for transversely collimating the radiation photons.

6. The system of claim 5 in which the predetermined width of each of the plurality of spaced longitudinal slits is configured to adjust spatial resolution of transverse collimation.

7. The system of claim 6 further including a plurality of slit-guides attached proximate each side of each of the plurality of longitudinal slits.

8. The system of claim 7 in which the angle of the slit-guides and the location of the spaced longitudinal slits are configured to provide a plurality of non-overlapping projections which define the size and location of the at least one predetermined imaging volume.

9. The system of claim 8 in which the size and location of the at least one predetermined image volume and the plurality of non-overlapping projections provides high geometric efficiency in the detection of radiation photons emitted from the heart.

10. The system of claim 8 in which the at least one predetermined image volume is configured for patients having different thoracic contours and/or different sized hearts and/or different locations of the heart relative to a predefined central axis.

11. The system of claim 8 in which the at least one predetermined imaging volume includes a large three-dimensional imaging volume for generating a scout image which estimates a three-dimensional center of the heart and the general size of the heart.

12. The system of claim 8 in which the at least one predetermined imaging volume includes a small three-dimensional imaging volume for generating SPECT images of the heart.

13. The system of claim 12 in which the combination of the location of spaced longitudinal slits, the angle of the slit-guides, and the distance between the slit-plate and the detector subsystem are adjusted for minification of a plurality of simultaneous non-overlapping projections cast on the detection system to provide high geometric efficiency for generating one or more SPECT images.

14. The system of claim 13 in which the one or more SPECT images are obtained by using image reconstruction of the plurality of simultaneous non-overlapping projections.

15. The system of claim 8 in which the collimator subsystem includes a plurality of transversely spaced slats disposed behind the slit-plate for longitudinally collimating the radiation photons.

16. The system of claim 15 in which the location of each of the plurality of transversely spaced slats is configured to adjust spatial resolution of longitudinal collimation.

17. The system of claim 16 in which the transversely spaced slats are configured to converge on predetermined focal points of a cone-beam of radiation photons emitted from the heart for increasing the number of radiation photons detected by the detector subsystem.

18. The system of claim 8 in which the slit-plate is configured as a flexible loop moveably coupled to the frame having a plurality of sections each configured to provide a unique predetermined imaging volume having a predetermined size and location, and a spatial resolution.

19. The system of claim 18 in which a desired section of the flexible loop is positioned proximate and surrounding the at least one predetermined imaging volume of the patient by driving the flexible loop to a predetermined location on the collimator subsystem.

20. The system of claim 19 further including a plurality of connected flexible loops moveably coupled to the frame, each loop including a plurality of sections configured to provide a unique predetermined imaging volume of a predetermined size, location, and spatial resolution.

21. The system of claim 8 further including a patient positioning subsystem for positioning the patient such that the heart is located proximate the center of the predetermined imaging volume based on previous scout images of the heart.

22. The system of claim 21 in which the patient positioning subsystem incrementally rotates the patient about a central longitudinal axis of the at least one predetermined imaging volume for obtaining a plurality of images.

23. The system of claim 22 in which the patient positioning subsystem intermittently and incrementally rotates the patient about a predefined central longitudinal axis of a small predetermined three-dimensional imaging volume for obtaining a plurality of sequentially acquired sets of simultaneous projections and reconstructing a one or more SPECT images.

24. The system of claim 22 in which the patient positioning subsystem positions the patient at predetermined locations of the central longitudinal axis to position the predetermined imaging volume at the appropriate position to increase sensitivity and improve image quality.

25. The system of claim 17 in which a patient positioning subsystem positions the predefined imaging volume encompassing the heart up and down about a longitudinal axis for acquiring additional imaging data in a longitudinal plane.

26. The system of claim 1 further including a source of radiation for emitting a beam of radiation photons towards and encompassing the three-dimensional imaging volume and the thorax of the patient.

27. The system of claim 26 in which the collimator system includes a plurality of vertical slats configured to define a plurality of longitudinal slits of a predetermined width for transversely collimating the beam of radiation photons.

28. The system of claim 27 in which the plurality of longitudinal slits have non-uniform widths for focusing on the source of radiation and optimizing collimation of the radiation photons emitted from the source of radiation

29. The system of claim 28 in which the vertical slats are configured to aim at the source of radiation.

30. The system of claim 29 in which the collimator subsystem includes a plurality of transversely spaced parallel slats disposed behind the vertical slats for longitudinally collimating the beam of radiation photons.

31. The system of claim 30 in which the distance between each of the plurality of transversely spaced slats is configured to adjust spatial resolution of longitudinal collimation.

32. The system of claim 31 in which the source of radiation photons includes a line source for emitting a three-dimensional fan beam of radiation photons which encompasses the three-dimensional imaging volume.

33. The system of claim 30 in which the source of radiation includes a longitudinal scanning point source configured to emit a three-dimensional fan beam of radiation photons which encompasses the three-dimensional imaging volume.

34. The system of claim 26 in which the source of radiation photons includes a point source for emitting a three-dimensional cone beam of radiation photons which encompasses the three-dimensional imaging volume.

35. The system of claim 33 in which the collimator subsystem includes a plurality of transversely spaced slats converging on a predetermined focal point of the point source for collimating the cone beam of radiation photons and for increasing the amount of radiation photons detected by the detector subsystem.

36. The system of claim 34 in which the distance between each of the plurality of spaced converging slats is configured to adjust the spatial resolution of longitudinal collimation.

37. The system of claim 33 in which the point source includes an x-ray tube.

38. An integrated single photon emission computed tomography (SPECT)/transmission computed tomography (TCT) system for cardiac imaging comprising:

an open arc-shaped frame;

a collimator system shaped to approximately match the thoracic contour of patients having different sizes and weights and shaped to surround and position the collimator closely proximate a heart of a patient of said patients encompassed by at least one predetermined image volume for optimizing collimation of radiation photons emitted from the heart;

an arc-shaped detector system coupled to the collimator subsystem having a shape closely matching the shape of the collimator subsystem for detecting collimated radiation photons from the collimator subsystem and generating output electrical signals;

a patient positioning system for positioning a patient to and about a predetermined central longitudinal axis of a three-dimensional imaging volume of the patient;

a movable source of radiation for emitting a beam of radiation photons to and encompassing the three-dimensional imaging volume; and

wherein the movable point source is rotated in one direction about the central longitudinal axis and the patient is rotated in an opposite direction about the central longitudinal axis for generating a plurality of TCT images.

39. An integrated single photon emission computed tomography (SPECT)/transmission computed tomography (TCT) system for cardiac imaging comprising:

an open arc-shaped frame;

a collimator system shaped to approximately match the thoracic contour of patients having different sizes and weights and shaped to surround and position the collimator closely proximate a heart of a patient of said patients encompassed by at least one predetermined image volume for optimizing collimation of radiation photons emitted from the heart, the collimator subsystem further including plurality of transversely spaced slats converging on a predetermined focal point of an x-ray source emitting a three-dimensional cone beam of radiation photons which encompasses the three-dimensional imaging volume for optimizing collimation of the cone beam of radiation photons;

an arc-shaped detector system coupled to the collimator subsystem having a shape closely matching the shape of the collimator subsystem for detecting collimated radiation photons from the collimator subsystem and generating output electrical signals; and

a patient positioning subsystem for positioning a patient to a predetermined central longitudinal axis of the three-dimensional imaging volume and for intermittently and incrementally rotating the patient about the predetermined central longitudinal axis for generating a plurality of TCT images.