Single photon emission computed tomography (SPECT) system for cardiac imaging

• US 20080135768A1
• 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 7,683,331 B2
• Time in Patent Office: Days
• US Class Current: 250/363.04
• CPC Class Codes: A61B 6/037 Emission tomography
• CPC Class Codes: G01T 1/1642 using a scintillation crystal and position sensing photodetector arrays, e.g. ANGER cameras
• CPC Class Codes: G01T 1/1648 Ancillary equipment for scintillation cameras, e.g. reference markers, devices for removing motion artifacts, calibration devices adapted for flow studies G01T1/1647

Abstract

A single photon emission computed tomography (SPECT) system for cardiac imaging including an open arc-shaped frame. A collimator subsystem is shaped to approximately match the thoracic contour to optimize the geometric efficiency for detecting photons emitted from the heart of patients having different sizes and weights and shaped to surround and position the collimator subsystem closely proximate a heart of a patient of the patients encompassed by at least one predetermined image volume for optimizing collimation of radiation photons emitted from the heart. The collimator subsystem is facilitated by a tracking system that is capable of quickly bringing up the collimator component, which meets a specific set of collimation requirements, into place for imaging. And an open 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.

Claims

1. A single photon emission computed tomography (SPECT) system for cardiac imaging comprising:

an open arc-shaped frame;

a collimator subsystem having an open arc-shape shaped to approximately match the thoracic contour of patients having different sizes and weights and shaped to surround and position the collimator subsystem 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; and

an open 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.

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 that 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 and the 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 such that a maximum number of projections can be 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 to accommodate cone-beams 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 additional projection 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 one or more SPECT images.

24. 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 cone-beam data set in a longitudinal plane.

25. The system of claim 1 in which the open arc-shaped frame has a shape closely matching the shape of the collimator subsystem.

26. A single photon emission computed tomography (SPECT) system for cardiac imaging comprising:

an open arc-shaped frame;

a collimator subsystem shaped to approximately match the thoracic contour of patients having different sizes and weights and shaped to surround and position the collimator subsystem 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 open 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 the patient such that the heart is located proximate the center of the predetermined imaging volume configured to optimize SPECT imaging based on previous scout images of the heart.

27. A single photon emission computed tomography (SPECT) system for cardiac imaging comprising:

an open arc-shaped frame;

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

an open 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.