Radioimaging

• US 20080230702A1
• Filed: 10/31/2007
• Published: 09/25/2008
• Est. Priority Date: 11/09/2004
• Status: Active Grant

• Current Assignee: Spectrum Dynamics Medical Ltd
• Original Assignee: Spectrum Dynamics LLC
• Inventors: Rousso, Benny, Ben-Haim, Shlomo, Vallabhajosula, Shankar, Dickman, Dalia, Nagler, Michael, Zilberstein, Yoel, Melman, Haim, Ravhon, Ran, Bronshtine, Zohar, Ziv, Omer, Berman, Daniel, Weissberg, Nir, Ben-Haim, Simona, Dichterman, Eli, Roth, Nathaniel, Popper, Ziv
• Granted Patent: US 8,445,851 B2
• Time in Patent Office: Days
• US Class Current: 250/363.02
• CPC Class Codes: A61B 5/4064 Evaluating the brain A61B5/031, A61B5/369, A61B5/14553 take precedence
• CPC Class Codes: A61B 5/4076 Diagnosing or monitoring particular conditions of the nervous system A61B5/4821, A61B5/4824 take precedence
• CPC Class Codes: A61B 5/417 the bone marrow
• CPC Class Codes: A61B 6/037 Emission tomography
• CPC Class Codes: A61B 6/4258 for detecting non x-ray radiation, e.g. gamma radiation A61B6/037 takes precedence
• CPC Class Codes: G01T 1/1603 with a combination of at least two different types of detector see provisionally also G01T1/16
• CPC Class Codes: G01T 1/161 Applications in the field of nuclear medicine, e.g. in vivo counting apparatus for radiation diagnosis A61B6/00
• 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

Radioimaging methods, devices and radiopharmaceuticals therefor.

Claims

1. A method of identifying preferred sets of views for radioactive-emission measurements of a region of interest within the body, comprising:

(a) providing a model of the region of interest;

(b) identifying a preferred set of views for the model.

2. A method according to claim 1, wherein said identifying comprises identifying using at least one information theoretic measure.

3. A method according to claim 1, comprising imaging a region of interest in a body using said set of views.

4. A method according to claim 3, comprising zooming in on said region of interest in said imaging.

5. A method is of radioimaging including a prescan, comprising:

(a) performing a fast prescan of a subject undergoing diagnosis;

(b) identifying a region-of-interest from said prescan; and

(c) collecting radiation data from the region-of-interest.

6. A method according to claim 5, wherein said prescan is performed using an imaging modality other than radiation.

7. A radioactive emission camera comprising a plurality of detection, amplification and signal processing paths configured to avoid saturation due to single hot sources.

8. A camera according to claim 7, wherein said paths channel at least 256 pixels in parallel to an image reconstructing system.

9. A method of radiation imaging, comprising:

(a) acquiring a first “

round”

of radioactive-emission measurements;

(b) updating a preferred set of views for a next “

round”

of radioactive-emission measurements; and

(c) performing said next round based on said updating, within less than 5 minutes.

10. A method according to claim 9, wherein said updating comprises updating according to a determination of detector utilization.

11. A method according to claim 10, wherein said utilization comprises saturation.

12. A method according to claim 10, wherein said utilization comprises low counts.

13. A method according to claim 9, wherein said updating comprises analyzing based on a reconstruction of the body structure, and choosing a preferred set of views for one or more of, better defining edges, ensuring a total count per voxel that meets a desired signal to nose ratio, and other image quality measures.

14. A method of estimating Compton scatter, comprising estimated using an iterative Expectation Maximization (EM) method which converges to a local maximum of a likelihood.

15. A method of estimating Compton scatter for two or more isotopes, comprising:

(a) defining the intensity density of each isotope i in a voxel u and the probability of a photon emitted from isotope i in voxel u, to be detected by a detector t at energy bin b.

(b) using the Compton-scatter equation for the change of the angle θ

of a photon emitted at energy E₀, and scattered to energy E, and modeling the random count X_tbⁱ(u) of photons, emitted from a voxel u and detected in measurement tb, of detector t at energy bin b, by a Poisson process with mean Σ

_tφ

_tbⁱ(u)Iⁱ(u);

(c) setting the total count of photons detected in measurement tb to be Y_tb=Σ

_uX_tb(u); and

(d) reconstructing the intensities Iⁱ(u) from the measurements y_tb using an iterative Expectation Maximization (EM) method.

16. A method of radioactive-emission imaging of a heart comprising:

imaging the heart of a body, for an imaging period greater than at least 2 cardiac electrical cycles;

post processing for identifying an average RR interval, based on actual RR intervals for the body;

post processing for evaluating each specific cardiac electrical cycle, vis a vis the average RR interval, and identifying each of the specific cardiac electrical cycles, either as “

good,”

which is to be included in the imaging, or as “

bad,”

which is to be discarded;

dividing each of the “

good”

cardiac electrical cycles to a predetermined number of time graduations;

indexing each graduation with cardiac-cycle indices; and

adding up photon counts that occurred within the graduations of the same cardiac-cycle index.

17. A method according to claim 16, comprising applying respiratory gating by providing respiratory cycle indices and adding up photon counts that occurred within the graduations of common cardiac-cycle and respiratory-cycle indices.

18. A method of radioactive-emission imaging of a heart with gating, comprising:

imaging the heart for an imaging period greater than at least 2 cardiac electrical cycles;

providing a graduation time scale, of predetermined graduations, in which at least one graduation mark is operative as a point of alignment;

aligning the point of alignment with a specific stage of each of the cardiac electrical cycles; and

allowing for a discard zone, between adjacent ones of the dedicated graduation time scales, where necessary,

so that all cardiac cycles have graduation time scales of substantially equal graduations, and the alignment of all cardiac cycles with the graduation time scales are substantially the same.

19. A method according to claim 18, wherein the imaging is performed by a plurality of detecting units, which image the heart in stepped motions.

20. A method according to claim 18, wherein, the detecting units are moved to new viewing positions at a predetermined stage of the cardiac electrical cycle.

21. A method according to claim 20, wherein the moving is at a stage associated with the discard zone.

22. A method of cardiac imaging, comprising

providing a radiation camera;

imaging the heart for an imaging period which is greater than a single cardiac cycle;

dividing at least a part of said cycle into bins;

binning received radiation according to said bins;

and reconstructing an image of said heart in less than one minute, for a plurality of bins.

23. A method according to claim 22, wherein said camera comprises a plurality of detecting units, for which time, position and viewing angle are substantially known for every detected photon;

said imaging period is less than two cardiac electrical cycles;

said divided part is an rr interval;

said binning comprises for each voxel of a reconstructed image, adding up photon counts, which occurred within a bin, for that voxel, from the different detecting units, and

comprising determining a rate of volumetric change during the cardiac electrical cycle.

24. A method according to claim 23, wherein the method further includes determining the maximum and minimum cardiac volumes during the cardiac electrical cycle.