# US 10,502,846 B2 · Normalization correction for multiple-detection enhanced emission tomography

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- Number: US 10,502,846 B2
- Document ID: US10502846B2
- Status: Granted
- Kind: B2
- Application number: 14/897,105
- Filed: 2014-06-24
- Published: 2016-05-12
- Granted: 2019-12-10
- Earliest claimed: 2013-06-24
- Assignees: Massachusetts Institute of Technology
- Applicants: Eduardo M. Lage; Joaquin L. Herraiz; Vicente J. Parot; Shivang R. Dave
- Inventors: Eduardo M. Lage; Joaquin L. Herraiz; Vicente J. Parot; Shivang R. Dave
- Web page: https://patentgrep.com/patent/US10502846B2

## CPC

- 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)}
- A61B 6/037: {Emission tomography}
- A61B 6/481: {involving the use of contrast agents}
- A61B 6/5205: {involving processing of raw data to produce diagnostic data}
- A61B 6/5217: {extracting a diagnostic or physiological parameter from medical diagnostic data}
- A61B 6/5258: {involving detection or reduction of artifacts or noise}
- G01T 1/1647: {Processing of scintigraphic data (not related to a particular imaging system G01T1/2992)}
- A61B 6/4258: {for detecting non x-ray radiation, e.g. gamma radiation (A61B6/037 takes precedence)}
- A61B 6/508: {for non-human patients}
- G01T: MEASUREMENT OF NUCLEAR OR X-RADIATION (radiation analysis of materials, mass spectrometry G01N23/00; tubes for determining the presence, intensity, density or energy of radiation or particles H01J47/00)
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)

## Abstract

A method and system for acquiring a series of medical images includes acquiring imaging data, identifying double coincidence events and multiple detection (MD) coincidence events from the imaging data, and storing the double coincidence events and the MD coincidence events in a first dataset and a second dataset, respectively. The method also includes applying a normalization correction to the first dataset and/or the second dataset using normalization values based on double coincidence events and/or MD coincidence events to obtain at least one normalized dataset, and reconstructing a series of medical images of the subject from the at least one normalized dataset.

## Claims

### Claim 1

An emission tomography system for acquiring a series of medical images of a subject, the system comprising:
a plurality of radiation detectors configured to be arranged around the subject to acquire photons emitted from the subject as a result of a radionuclide administered to the subject and communicate signals corresponding to acquired photons;
a data processing system configured to:
receive the signals from the plurality of detectors,
determine, from at least the signals from the plurality of detectors, coincidence events including photon coincidence events involving two photons and photon coincidence events involving at least three photons,
map the photon coincidence events involving two photons to projected lines of response,
map the photon coincidence events involving at least three photons to the projected lines of response,
apply a first normalization correction to the mapped coincidence events involving two photons based on a first normalization using two-photon events, and
apply a second normalization correction to the mapped photon coincidence events involving at least three photons based on a second normalization using coincidence events involving at least three photons; and
a reconstruction system configured to:
receive from the data processing system an array of normalized photon coincidence events involving two photons,
receive from the data processing system an array of normalized photon coincidence events involving at least three photons, and
reconstruct therefrom a series of medical images of the subject.

### Claim 2 (depends on 1)

The system of claim 1 wherein the data processing system is further configured to identify timing information and energy information of the acquired photons, wherein the timing information is identified with sufficient resolution to determine the photon coincidence events involving two photons and the photon coincidence events involving at least three photons.

### Claim 3 (depends on 2)

The system of claim 2 wherein the timing resolution is at least one of nanosecond and picosecond resolution.

### Claim 4 (depends on 2)

The system of claim 2 wherein the photon coincidence events involving at least three photons are mapped to the projected lines of response based on the timing information and the energy information.

### Claim 5 (depends on 1)

The system of claim 1 wherein the reconstruction system is further configured to map photon coincidence events involving at least three photons based on the mapped photon coincidence events involving two photons.

### Claim 6 (depends on 1)

The system of claim 1 wherein the photon coincidence events involving at least three photons are determined by a first set of factors and the photon coincidence events involving two photons are determined by a second set of factors, different from the first set of factors.

### Claim 7 (depends on 1)

The system of claim 1 wherein data for the first normalization using two-photon events and data for the second normalization using photon coincidence events involving at least three photons are obtained from a single acquisition.