Techniques for Producing an Image of Radioactive Emissions Using a Compton Camera

Patent metadata

Field	Value
Publication number	US-2018188392-A1
Application number	US-201615738597-A
Country	US
Kind code	A1
Filing date	Jun 24, 2016
Priority date	Jun 25, 2015
Publication date	Jul 5, 2018
Grant date	—

Abstract

Techniques for imaging radioactive emission in a target volume include collecting from each of multiple detectors in a Compton camera, within a coincidence time interval, location and deposited energy from an interaction associated with each high energy particle source event in a target volume, for N source events. A cone of possible locations for each source event is determined based on the locations and deposited energies collected. A SOE algorithm is initiated by selecting a random location on the cone and generating a histogram that indicates, a count of the selected locations that occur inside each voxel of the target volume. N solution locations for the N source events are determined after L iterations by updating the selected location on a corresponding cone based at least in part on values of the counts in the histogram excluding the current source event. A solution is presented on a display device.

First claim

1 . A method implemented on a processor comprising:
receiving data indicating a set of one or more known positions in a target volume of a subject associated with a cause of a high energy particle source event; collecting from each of a plurality of detectors in one or more stages of a Compton camera within a coincidence time interval, location and deposited energy from an interaction associated with a single source event in the target volume of the subject; determining for the source event a cone of possible locations for the source event based on the locations and deposited energies collected from the plurality of detectors in one or more stages of the Compton camera; and selecting a particular location on the cone within the target volume based on proximity to the set of one or more known positions in the target volume; and presenting, on a display device, data indicating the particular location in the target volume.

2 . The method of claim 1 , wherein the source event is a gamma ray emission and the cause of the source event is a proton beam interacting with an atom in the subject.

3 . The method of claim 1 , wherein the source event is a gamma ray emission and the cause of the source event is a positron-emitting radionuclide as used in positron emission tomography (PET) medical imaging.

4 . The method of claim 3 , wherein collecting from each of the plurality of detectors in one or more stages of the Compton camera within the coincidence time interval, location and deposited energy from the interaction associated with the source event in the target volume of the subject further comprises selecting from each of only two detectors in one or more stages of the Compton camera within the coincidence time interval, location and deposited energy wherein a sum of the deposited energies in the two detectors is about equal to an energy of a gamma ray emitted by annihilation of the positron produced by the positron-emitting radionuclide.

5 . The method of claim 1 , wherein the source event is a gamma ray emission and the cause of the source event is a gamma-emitting radioisotope as used in single-photon emission computed tomography (SPECT) medical imaging.

6 . The method of claim 5 , wherein collecting from each of the plurality of detectors in one or more stages of the Compton camera within the coincidence time interval, location and deposited energy from an interaction associated with the source event in the target volume of the subject further comprises selecting from each of only two detectors in one or more stages of the Compton camera within the coincidence time interval, location and deposited energy wherein a sum of the deposited energies in the two detectors is about equal to an energy of a gamma ray emitted by the gamma-emitting radioisotope.

7 . A computer-readable medium carrying one or more sequences of instructions, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of the method of claim 1 .

8 . A system comprising:
a Compton camera comprising a plurality of detectors in one or more stages, each stage comprising an array of detectors for a high energy particle; at least one processor; and at least one memory including one or more sequences of instructions, the at least one memory and the one or more sequences of instructions configured to, with the at least one processor, cause the system to perform at least the steps of the method of claim 1 .

9 . A method implemented on a processor comprising:
receiving first data indicating locations of a plurality of voxels of target resolution v in a target volume of a subject; collecting from each of a plurality of detectors in one or more stages of a Compton camera within a coincidence time interval, location and deposited energy from an interaction associated with each high energy particle source event in the target volume, for a plurality of N source events in the target volume; determining for each source event a cone of possible locations for the source event based on the locations and deposited energies collected from the plurality of detectors in one or more stages of the Compton camera; initiating a stochastic origins ensemble (SOE) iterative algorithm by
selecting for each source event a random location on the cone of possible locations for a corresponding source event and
generating a histogram that indicates, for each voxel, a count of the selected locations that occur inside the voxel;
determining a solution comprising a set of N solution locations for the N source events from the SOE iterative algorithm after L iterations by
updating for each source event during each iteration the selected location on the corresponding cone based at least in part on values of the counts in the histogram excluding the current source event, and
updating the histogram based on the updated selected location for each source event during each iteration; and,
presenting, on a display device, data indicating at least one solution location of the set of N solution locations.

10 . The method of claim 9 , wherein each of the plurality of N source events is used once without replacement as the current source event, during each iteration of the L iterations.

11 . The method of claim 9 , wherein the source event is a gamma ray emission and the cause of the source event is a proton beam interacting with an atom in the subject.

12 . The method of claim 9 , wherein the source event is a gamma ray emission and the cause of the source event is a positron-emitting radionuclide as used in positron emission tomography (PET) medical imaging.

13 . The method of claim 12 , wherein collecting from each of the plurality of detectors in one or more stages of the Compton camera within the coincidence time interval, location and deposited energy from an interaction associated with the source event in the target volume further comprises selecting from each of only two detectors in one or more stages of the Compton camera within the coincidence time interval, location and deposited energy wherein a sum of the deposited energies in the two detectors is about equal to an energy of a gamma ray emitted by annihilation of the positron produced by the positron-emitting radionuclide.

14 . The method of claim 9 , wherein the source event is a gamma ray emission and the cause of the source event is a gamma-emitting radioisotope as used in single-photon emission computed tomography (SPECT) medical imaging.

15 . The method of claim 14 , wherein collecting from each of the plurality of detectors in one or more stages of the Compton camera within the coincidence time interval, location and deposited energy from an interaction associated with the source event in the target volume further comprises selecting from each of only two detectors in one or more stages of the Compton camera within the coincidence time interval, location and deposited energy wherein a sum of the deposited energies in the two detectors is about equal to an energy of a gamma ray emitted by the gamma-emitting radioisotope.

16 . A computer-readable medium carrying one or more sequences of instructions, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of the method of claim 9 .

17 . A system comprising:
a Compton camera comprising a plurality of detectors in one or more stages, each stage comprising an array of detectors for a high energy particle; at least one processor; and at least one m

Assignees

• Univ Maryland
• Univ Of Baltimore Maryland

Inventors

• Polf Jerimy
• Draeger Emily
• Peterson Stephen
• Mackin Dennis
• Beddar A Sam

Classifications

• G06T11/26

  Drawing of charts or graphs · CPC title

• A61N2005/1087

  Ions; Protons · CPC title

• G06T2210/41

  Medical · CPC title

• G01T1/29 Primary

  Measurement performed on radiation beams, e.g. position or section of the beam; Measurement of spatial distribution of radiation · CPC title

• G01T1/1642

  using a scintillation crystal and position sensing photodetector arrays, e.g. ANGER cameras · CPC title