Large-area detector apparatus for photosensor, radiation detector, and medical pet scanner applications

Patent metadata

Field	Value
Publication number	US-2017123084-A1
Application number	US-201615350943-A
Country	US
Kind code	A1
Filing date	Nov 14, 2016
Priority date	May 15, 2014
Publication date	May 4, 2017
Grant date	—

Abstract

A large area position-sensitive single-photon detector and radiation detector is described. Photon detectors are coupled to a large area panel configured with an equipotential feedthrough chamber that operates in combination with a photocathode of a hemispherical window to provide electrostatic focusing for the photoelectrons. The panels can be assembled into an enveloping structure, such as a PET scanner, which is globally and/or locally curved, such as into a sphere, ovoid, elongated cylinder, or similar structure providing significant sensitive surface surrounding an object, such as a patient being scanned in a medical positron emission tomography (PET) scanner. Increased sensitivity is provided in response to registering radiation by surrounding the patient, so that reduced patient radiation dosing levels are required.

First claim

What is claimed is:

1 . A photo-radiation detector panel apparatus, comprising:
(a) a base structure; (b) a plurality of photon detectors, each having a hemispherical window with a photocathode layer, and with an electron detector centered beneath the hemispherical window, each of said photon detectors having an electrical and physical connection to said base structure; and (c) an upper plate and a lower plate of said base structure between which is disposed an equipotential feedthrough chamber; (d) wherein said upper plate and said photocathode of each of said plurality of photon detectors is retained at a first voltage level, while said lower plate and a ring of material around said electron detector in said upper plate, are retained at a second voltage level, in which the difference between said first and second voltage level is a high voltage; (e) wherein photons striking said photocathode layer are converted to photoelectrons, which are then directed by electrostatic field lensing in response to local voltage gradients of said electron detector which outputs a signal; and (f) wherein said equipotential feedthrough chamber operates in combination with said photocathode layer of the hemispherical window and all other conductive surfaces to provide proper electrostatic lensing for the photoelectrons, by extending said electrical equipotential surfaces from said hemispherical window through said base structure between each of said plurality of photon detectors.

2 . The apparatus as recited in claim 1 , wherein said electron detector comprises a scintillator layer positioned beneath said photocathode within said hemispherical window, and transmitting generated light to a photosensor mounted outside of said hemispherical window.

3 . The apparatus as recited in claim 1 , wherein said photon detector comprises a scintillator based electron detector.

4 . The apparatus as recited in claim 3 , wherein said scintillator in said scintillator based electron detector is selected from the group of scintillating materials consisting of YAP, YAG, GSO, LYSO, LSO, LaBr: Ce, and CeBr.

5 . The apparatus as recited in claim 1 , wherein said equipotential feedthrough chamber extends equipotential surfaces within a base structure, instead of closing the equipotential surfaces in a dome structure behind each photon detector.

6 . The apparatus as recited in claim 1 , wherein said upper plate comprises a printed circuit board (PCB).

7 . The apparatus as recited in claim 6 , wherein said PCB comprises a material selected from the group of PCB material consisting of: copper-clad-fiberglass, G−10 board, glass, fused silica, quartz, Teflon, and Teflon composites.

8 . The apparatus as recited in claim 1 , wherein said lower plate comprises a solid conductive material layer or a printed circuit board (PCB).

9 . The apparatus as recited in claim 1 , wherein an electrical insulator is disposed between said upper plate and said lower plate as said equipotential feedthrough chamber.

10 . The apparatus as recited in claim 1 , wherein power and signal line connections to said photon detector pass through a hollow conductive bridge connecting between said first and said second layers retained at said second voltage level.

11 . The apparatus as recited in claim 1 , wherein said hemispherical window, photocathode, and said electron detector comprise a photon detector unit which is evacuated and hermetically sealed to maintain a vacuum in its evacuated space.

12 . The apparatus as recited in claim 1 , further comprising a scintillator layer disposed over said hemispherical windows of said plurality of photon detectors, for providing conversion of gamma rays into visible light.

13 . The apparatus as recited in claim 12 , further comprising a light distribution layer, disposed between said scintillator layer and said hemispherical windows of said plurality of photon detectors, for spreading photons generated in the scintillator over several of said photon detectors.

14 . The apparatus as recited in claim 1 , further comprising a light distribution layer, disposed over said hemispherical windows of said plurality of photon detectors, for spreading photons generated in the scintillator over several of said photon detectors.

15 . The apparatus as recited in claim 1 , wherein said position-sensitive photo-radiation detector panels are configured for use in detecting visible or UV light, or for detecting gamma-ray radiation.

16 . The apparatus as recited in claim 1 ,
wherein said detector comprises a scintillator based gamma-ray detector; and wherein a sufficient number of said position-sensitive gamma-ray detector panels are interconnected into a substantially enclosed positron emission tomography (PET) system configured for detecting gamma-ray pairs.

17 . The apparatus as recited in claim 15 , wherein said substantially enclosed PET system provides a detection envelope with three dimensional curving around both longitudinal axis, and transverse axis, of a patient's body, in which the three dimensional curving limits parallax error.

18 . The apparatus as recited in claim 15 , wherein said substantially enclosed PET system is configured for imaging the entirety of the patient's body in a single scan without the need for sequential scanning operations while the body of a patient is moved through a PET scanner.

19 . The apparatus as recited in claim 15 , wherein said substantially enclosed PET system has an inner diameter of 0.8 to 3 meters, and a length of from 2 to 4 meters.

20 . A positron emission tomography (PET) apparatus, comprising:
(a) a structure configured for substantially enclosing a patient during a PET scan; and (b) a plurality of gamma-ray detector panels retained within said structure, and configured for detecting gamma rays emerging from the patients entire body in a single PET scan.

21 . A positron emission tomography (PET) apparatus, comprising:
(a) a structure configured for substantially enclosing a patient during a PET scan; (b) a plurality of gamma-ray detector panels having a scintillator and a photon detector, said gamma-ray detector panels are retained within said structure, and configured for detecting gamma rays emerging from the patients entire body in a single PET scan; (c) a hemispherical window with a photocathode layer, and with a scintillator-based electron detector centered beneath the hemispherical window in each of said photon detectors, within which evacuated space is maintained; and (d) an upper plate and a lower plate having conductors for conveying a first and second voltage potential, between which is disposed an equipotential feedthrough chamber; (e) wherein said upper plate and said photocathode of each of said plurality of photon detectors is retained at a first voltage level, while said lower plate and a ring of material around said plurality of photon detectors in said upper plate, are retained at a second voltage level, in which the difference between said first and second voltage level is a high voltage; (f) wherein photons striking said photocathode layer are converted to photoelectrons directed by electrical field lensing in response to local voltage gradients to said scintillator-based electron detector which outputs an amplified electronic signal; and (g) wherein said equipotential feedthrough chamber operates in combination with said photocathode layer of the hemispherical window to provide proper electrostatic lensing for the photoelectrons

Assignees

• Univ California

Inventors

• Ferenc Daniel

Classifications

• 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

• G01T1/20188

  Auxiliary details, e.g. casings or cooling · CPC title

• A61B6/037

  Emission tomography · CPC title