System and method for tomography combining single and paired photons

• US 8,183,531 B2
• Filed: 05/21/2008
• Issued: 05/22/2012
• Est. Priority Date: 05/21/2007
• Status: Active Grant

• Current Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Original Assignee: Board of Trustees of the Leland Stanford Junior University (Stanford Management Co.)
• Inventors: Chinn, Garry, Levin, Craig S., Foudray, Angela M.
• Primary Examiner(s): Porta, David
• Assistant Examiner(s): Maupin, Hugh H
• Application Number:
  US12/154,206
• Publication Number:
  US 20090072156A1
• Time in Patent Office: 1,462 Days
• Field of Search: 250/252.1, 250/361.R, 250/362, 250/363.01, 250/363.02, 250/363.03, 250/363.04, 250/369, 250/371, 250/391
• US Class Current: 250/363.04
• CPC Class Codes: A61B 6/037 Emission tomography
• CPC Class Codes: A61B 6/508 for non-human patients
• CPC Class Codes: G01T 1/2985 In depth localisation, e.g. using positron emitters; Tomographic imaging (longitudinal and transverse section imaging; apparatus for radiation diagnosis sequentially in different planes, steroscopic radiation diagnosis); using external radiation sources A61B6/02

Abstract

Methods and systems for producing an image. Measurement data is obtained for a coincidence photon event, and a line projector function is generated based on the obtained measurement data. Additional measurement data is obtained for a single photon event, and a cone-surface projector function is generated based on the additional measurement data. An image is reconstructed using the generated line projector function and the generated cone-surface projector function. In another example method for producing an image, a measurement is obtained, and a projector function is generated using the obtained measurement. The generated projector function is modified based on an a priori image. An image is reconstructed using the modified projector function.

Claims

1. A method for producing an image comprising:

obtaining measurement data for a coincidence photon event;

generating a line projector function based on the obtained measurement data;

obtaining additional measurement data for a single detected photon from an event other than the coincidence photon event;

generating a cone-surface projector function based on the additional measurement data;

combining data from said generated line projector function and said generated cone-surface projector function;

reconstructing an image using said combined data from said line projector function and said generated cone-surface projector function.

2. The method of claim 1, wherein said generating the cone-surface projector function uses Compton kinematics collimation.

3. The method of claim 1, wherein said generated line projector function provides a coincidence collimation channel and said generated cone-surface projector function provides a Compton kinematics collimation channel;

wherein said reconstructing an image further comprises;

combining data from the coincidence collimation channel and the Compton kinematics collimation channel.

4. The method of claim 3, wherein said combining comprises using data from the coincidence collimation channel simultaneously with data from the Compton kinematics collimation channel.

5. The method of claim 3, wherein said combining comprises using data from the coincidence collimation channel sequentially with data from the Compton kinematics collimation channel.

6. The method of claim 3, wherein said combining comprises using data from the coincidence collimation channel to reweight the cone-surface projector function.

7. The method of claim 3, wherein said combining comprises using data from the Compton kinematics collimation channel to reweight the line projector function.

8. The method of claim 1, wherein said obtaining measurement data for a coincidence photon event comprises:

producing a photon interaction in each of a pair of detectors;

for each of the pair of detectors, determining a position and energy of the produced photon interaction.

9. The method of claim 1, wherein said obtaining additional measurement data for the single detected photon comprises:

producing at least two photon interactions in a detector;

determining a position and energy of the produced at least two photon interactions.

10. The method of claim 1, wherein said reconstructing an image uses an image reconstruction algorithm.

11. A system for radiation-based imaging comprising:

a plurality of 3-D detectors disposed with respect to a source of emitted photons to receive the emitted photons and produce interactions, the interactions detecting at least coincidence photons from a coincidence photon event and, additionally, single detected photons from events other than the coincidence photon event;

an image generator coupled to said plurality of 3-D detectors to receive a position and energy for the produced interactions and reconstruct an image;

said image generator being configured to generate a line projector function based on the detected coincidence photons and a cone-surface projector function based on the additional single detected photons, combine data from the generated line projector function and the generated cone-surface projector function, and reconstruct an image using the combined data from the generated line projector function and the cone-surface projector function.

12. The system of claim 11, wherein the generated line projector function provides a coincidence collimation channel and the generated cone-surface projector function provides a Compton kinematics collimation channel;

wherein reconstructing the image further comprises;

combining data from the coincidence collimation channel and the Compton kinematics collimation channel.

13. The system of claim 12, wherein the combining comprises at least one of using data from the coincidence collimation channel simultaneously with data from the Compton kinematics collimation channel, and using data from the coincidence collimation channel sequentially with data from the Compton kinematics collimation channel.

14. The system of claim 12, wherein the combining comprises at least one of using the coincidence collimation channel to reweight the cone-surface projector function, and using data from the Compton kinematics collimation channel to reweight the line projector function.

15. The system of claim 11, wherein said plurality of 3-D detectors comprises cadmium zinc telluride (CZT) detectors.

16. The system of claim 11, wherein said image generator comprises a computing device.

17. An image generator comprising:

a computing device configured to perform a method comprising;

obtaining measurement data for a coincidence photon event;

generating a line projector function based on the obtained measurement data;

obtaining additional measurement data for a single detected photon from an event other than the coincidence photon event;

generating a cone-surface projector function based on the additional measurement data;

combining data from said generated line projector function and said generated cone-surface projector function; and

reconstructing an image using said combined data from said line projector function and said generated cone-surface projector function.

18. The image generator of claim 17, wherein said obtaining measurement data for a coincidence photon event comprises:

receiving a signal generated from a produced photon interaction in each of a pair of detectors;

for each of the pair of detectors, determining a position and energy of the produced photon interaction.

19. An apparatus for controlling a computing device comprising:

a non-transitory computer-readable medium containing computer-readable instructions that, when read, cause a computer to perform a method comprising;

obtaining measurement data for a coincidence photon event;

generating a line projector function based on the obtained measurement data;

obtaining additional measurement data for a single detected photon from an event other than the coincidence photon event;

generating a cone-surface projector function based on the additional measurement data;

combining data from said generated line projector function and said generated cone-surface projector function; and

reconstructing an image using said combined data from said line projector function and said generated cone-surface projector function.

20. the apparatus of claim 19, wherein said obtaining measurement data for a coincidence photon event comprises:

receiving a signal generated from a produced photon interaction in each of a pair of detectors;

for each of the pair of detectors, determining a position and energy of the produced photon interaction.