Positron-emission tomography detector systems based on low-density liquid scintillators and precise time-resolving photodetectors

Patent metadata

Field	Value
Publication number	US-10132942-B2
Application number	US-201615553275-A
Country	US
Kind code	B2
Filing date	Apr 8, 2016
Priority date	Apr 13, 2015
Publication date	Nov 20, 2018
Grant date	Nov 20, 2018

Abstract

TOF-PET detector systems, and methods for imaging photon-emitting samples using the detector systems, are provided. The TOF-PET detector systems use large-area photodetectors with extremely high time-resolution and an approach to data collection and analysis that allows for the use of inexpensive low-density scintillator materials. The TOF-PET detector systems are characterized by their ability to identify, on a statistical basis, the transverse and depth location of the first of the series of energy deposition events that are generated when a gamma photon enters the low-density scintillator material.

First claim

What is claimed is:

1. A time-of-flight positron-emission tomography detector system comprising:
a sample holder;
a first time-of-flight positron-emission tomography camera module comprising:
a first liquid scintillator material having a front face and a back face;
a first photodetector located on the front face of the first liquid scintillator material, wherein the first photodetector comprises a photocathode, at least one microchannel plate and one or more anodes; and
a second photodetector located on the back face of the first liquid scintillator material from the first photodetector, wherein the second photodetector comprises a photocathode, at least one microchannel plate and one or more anodes; and
a second time-of-flight positron-emission tomography camera module comprising:
a second liquid scintillator material having a front face and a back face;
a third photodetector located on the front face of the second liquid scintillator material, wherein the third photodetector comprises a photocathode, at least one microchannel plate and one or more anodes; and
a fourth photodetector located on the back face of the second liquid scintillator material from the third photodetector, wherein the fourth photodetector comprises a photocathode, at least one microchannel plate and one or more anodes;
wherein the second time-of-flight positron-emission tomography camera module is configured to face the first time-of-flight positron-emission tomography camera module and is located on an opposite side of the sample holder from the first time-of-flight positron-emission tomography camera module.

2. The detector system of claim 1 , wherein the first and second liquid scintillator materials are water based scintillator materials.

3. The detector system of claim 2 , wherein the water based scintillator materials are loaded with an element having an atomic number greater than 16.

4. The detector system of claim 1 , wherein the first and second time-of-flight positron-emission tomography camera modules further comprise absorbing surfaces, reflecting surfaces, or a combination thereof, disposed in or on a face of the first and second liquid scintillator materials and configured to constrain paths of radiation in the first and second liquid scintillator materials.

5. The detector system of claim 1 , wherein the first, second, third and fourth photodetectors have time resolutions of 40 psec (sigma) or better for a single photon.

6. The detector system of claim 5 , wherein the first, second, third and fourth photodetectors have time resolutions of 30 psec (sigma) or better for a single photon.

7. The detector system of claim 1 , wherein the first time-of-flight positron-emission tomography camera module is located above the sample holder and the second time-of-flight positron-emission tomography camera module is located below the sample holder, the detector system further comprising:
a third time-of-flight positron-emission tomography camera module comprising:
a third liquid scintillator material having a front face and a back face;
a fifth photodetector located on the front face of the third liquid scintillator material, wherein the fifth photodetector comprises a photocathode, at least one microchannel plate and one or more anodes; and
a sixth photodetector located on the back face of the third liquid scintillator material from the fifth photodetector, wherein the sixth photodetector comprises a photocathode, at least one microchannel plate and one or more anodes; and
a fourth time-of-flight positron-emission tomography camera module comprising:
a fourth liquid scintillator material having a front face and a back face;
a seventh photodetector located on the front face of the fourth liquid scintillator material, wherein the seventh photodetector comprises a photocathode, at least one microchannel plate and one or more anodes; and
an eighth photodetector located on the back face of the fourth liquid scintillator material from the seventh photodetector, wherein the eighth photodetector comprises a photocathode, at least one microchannel plate and one or more anodes;
wherein the fourth time-of-flight positron-emission tomography camera module is configured to face the third time-of-flight positron-emission tomography camera module and is located on an opposite side of the sample holder from the third time-of-flight positron-emission tomography camera module.

8. The detector system of claim 1 , further comprising:
a processor; and
a computer-readable medium operably coupled to the processor, the computer-readable medium having computer-readable instructions stored there on that, when executed by the processor:
identifies, on a statistical basis, the position of the first of a plurality of optical photon-emitting Compton Scattering and Photoelectric Effect energy deposition events resulting from an interaction of a first gamma ray of a coincident gamma ray pair with the first liquid scintillator material;
identifies, on a statistical basis, the position of the first of a plurality of optical photon-emitting Compton Scattering and Photoelectric Effect energy deposition events resulting from an interaction of a second gamma ray of the coincident gamma ray pair with the second liquid scintillator material; and
calculates the source position for the first and second gamma rays based on the positions of the identified first optical photon-emitting Compton Scattering or Photoelectric Effect energy deposition events in the first and second liquid scintillator materials.

9. The detector of claim 1 further comprising waveform sampling electronic circuitry in communication with the one or more anodes.

10. The detector of claim 1 , wherein the one or more anodes comprise transmission line anodes.

11. The detector of claim 1 , wherein the one or more anodes are pixel anodes comprising contact pads on a non-vacuum side of the anodes, the detector further comprising readout electronics connected to the pixel anodes.

12. The detector of claim 1 further comprising electronic circuitry connected to the first and second time-of-flight positron-emission tomography camera modules and adapted to detect a pair of coincident gamma rays emanating from a sample.

13. A method of imaging a gamma ray-emitting region in a sample, the method comprising:
placing a sample that emits coincident gamma ray pairs between a first time-of-flight positron-emission tomography camera module comprising a first scintillator material and a second time-of-flight positron-emission tomography camera module comprising a second scintillator material;
detecting coincident gamma ray pairs in which the first gamma ray interacts with a volume of the first scintillator material to produce a plurality of optical photon-emitting Compton Scattering and photoelectric energy deposition events in the same volume of the first scintillator material with which the first gamma ray interacted and the second gamma ray interacts with a volume of the second scintillator material to produce a plurality of optical photon-emitting Compton Scattering and photoelectric energy deposition events in the same volume of the second scintillator material with which the second gamma ray interacted;
determining source positions for the detected coincident gamma ray pairs by:
identifying, on a statistical basis, the first of the plurality of optical photon-emitting Compton Scattering and photoelectric energy deposition events produced in the first scintillator material by the first gamma ray of a coincident gamma ray pair;
identifying, on a statistical basis, the first of the plurality of optical photon-emitting Compton Scattering an

Assignees

• Univ Chicago
• Brookhaven Science Ass Llc

Inventors

• Frisch Henry J
• Oberla Eric J
• Kim Hee-Jong
• Yeh Minfang

Classifications

• A61B6/037

  Emission tomography · CPC title

• G01T1/2018

  Scintillation-photodiode combinations · CPC title

• G01T1/2985 Primary

  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) · CPC title

• G01T1/204

  the detector being a liquid · CPC title