REVERSE DATA RECONSTRUCTION FOR OPTIMAL TIME SAMPLING OF COUNTS IN PHYSIOLOGICAL LIST-MODE NUCLEAR IMAGING

• US 20110105887A1
• Filed: 05/29/2009
• Published: 05/05/2011
• Est. Priority Date: 06/13/2008
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Tipnis, Sameer, Muzic, Raymond, Gagnon, Daniel
• Granted Patent: US 8,437,836 B2
• Time in Patent Office: Days
• US Class Current: 600/410
• CPC Class Codes: A61B 6/037 Emission tomography
• CPC Class Codes: A61B 6/486 involving generating temporal series of image data
• CPC Class Codes: A61B 6/507 for determination of haemodynamic parameters, e.g. perfusion CT
• CPC Class Codes: G06T 11/006 Inverse problem, transformation from projection-space into object-space, e.g. transform methods, back-projection, algebraic methods
• CPC Class Codes: G06T 2211/412 Dynamic

Abstract

A diagnostic imaging device includes detector elements (16) for detecting y-rays indicative of nuclear decay events. Pairs of concurrently detected γ-rays define lines of response (LORs) which are collected, time stamped, and compiled in list-mode. In tissue perfusion studies, it is beneficial to use the data that concurrently maximizes contrast and signal-to-noise ratio in the reconstructed images. Using the list-mode data, events in an adjustable temporal window (33) are reconstructed and the reconstructed images are analyzed to determine a figure of merit based on contrast and signal-to-noise properties of the image. By iteratively adjusting the temporal window, extending its start point (36) backwards in time, and repeating the reconstructing, analyzing, and adjusting steps, an image with an optimal figure of merit is obtained.

Claims

1. A diagnostic imaging apparatus comprising:

a detector array for receiving events from an imaging region;

a triggering processor for assigning a time stamp to the received events;

a reconstruction processor that reconstructs an adjustable portion of the events into an image representation;

an analyzer that analyzes the reconstructed image representation to determine a parameter indicative of image quality and adjusts the adjustable portion of the verified events for reconstruction into a subsequent image representation in accordance with the determined parameter.

2. The diagnostic imaging apparatus as set forth in claim 1, wherein the determined parameter is a figure of merit based on a selected parameter of the image representation.

3. The diagnostic imaging apparatus as set forth in claim 1, further including:

an event storage buffer that stores verified events in a list that is sortable by time of receipt of the event; and

a temporal window selector which is controlled by the analyzer to adjust a temporal window that defines the events which are reconstructed.

4. The diagnostic imaging apparatus as set forth in claim 3, further including:

a display for displaying at least the temporal window to a user.

5. A method of diagnostic imaging comprising:

collecting a set of data points indicative of received nuclear decay events;

time stamping the received events;

reconstructing an image representation from an adjustable portion of the collected data points;

analyzing the image representation to determine a value of a parameter indicative of image representation quality; and

adjusting the adjustable portion of the collected data points which are used in reconstructing a subsequent image representation.

6. The method as set forth in claim 5, wherein the parameter determining step includes:

determining a figure of merit for the image representation.

8. The method as set forth in claim 6, wherein the figure of merit is a contrast-to-noise ratio of the image representation.

9. The method as set forth in claim 5, further including:

sorting the data points by time of detection, the portion of the data points being in an adjustable temporal window.

10. The method as set forth in claim 9, further including:

analyzing the subsequent image representations to determine a value of the parameter indicative of the second image representation quality;

in response to the values of the subsequent and previous image representation parameters indicating that the subsequent image is better than the previous image, adjusting the temporal window and generating another image representation.

11. The method as set forth in claim 10, wherein the temporal window has a start point and an end point and further including:

in response to the subsequent image being better than the previous image representation, moving the start point toward a beginning of the scan.

12. The method as set forth in claim 10, further including:

iteratively repeating the steps of adjusting, reconstructing, and analyzing until an image representation with value of the parameter is one of optimized or exceeds a selected threshold.

13. The method as set forth in of claim 9, further including:

displaying the window to a user.

14. The method as set forth in claim 9, further including:

analyzing the window to aid in one of a diagnosis, quantification, and a measure of a bodily process

15. A nuclear imaging system including a processor programmed to control the nuclear imaging system to perform the method of claim 5.

16. A computer readable medium carrying software to control a processor to perform the method of claim 5.

7. The method as set forth in 6, further including:

comparing the figure of merit for the subsequent image representation to the figure of merit for the previous image representation, and if the figure of merit for the subsequent image representation is greater than or equal to the figure of merit for the previous image representation, repeating further adjusting the portion of the collected data points that are used to reconstruct a next image representation.