Fiber optic gamma camera having scintillating fibers

• US 6,271,510 B1
• Filed: 08/11/1999
• Issued: 08/07/2001
• Est. Priority Date: 12/18/1998
• Status: Expired due to Fees

• Current Assignee: Izzie Boxen
• Original Assignee: Izzie Boxen
• Inventors: Boxen, Izzie
• Primary Examiner(s): LE, QUE TAN
• Application Number:
  US09/372,128
• Time in Patent Office: 727 Days
• Field of Search: 250/208.1, 250/207, 250/214.R, 250/227.2, 250/363.06, 250/363.1, 250/363-1-3, 250/214.VT, 250/216, 313/532, 313/534, 313/103.R, 313/103.CM, 378/21
• US Class Current: 250/208.1
• CPC Class Codes: A61B 6/4258 for detecting non x-ray radiation, e.g. gamma radiation A61B6/037 takes precedence
• CPC Class Codes: G01T 1/1644 using an array of optically separate scintillation elements permitting direct location of scintillations G01T1/1645 takes precedence
• CPC Class Codes: G01T 1/201 using scintillating fibres

Abstract

Apparatus for capturing two-dimensional images created by radioactive emanations, such as gamma rays, from a radioactive source, comprises a collimator, a two-dimensional array of scintillating fibers, and position encoding apparatus. The scintillating fibers are located at preselected x and y positions in an x-y plane. The position encoding apparatus comprises banks of photon detectors and a network of optical fibers which are connected to the photon detectors in a manner which encodes the x-y coordinates of the scintillating fibers, and a signal processor for generating position signals indicative of the encoded position of an active scintillating fiber.

Claims

1. Apparatus for capturing a two dimensional image created by particle emanations from a source, comprising:

a) collimator means for collimating the particle emanations and producing collimated emanations, comprising a collimator plate having a series of collimator apertures separated by septa made of a material capable of absorbing the emanations;

b) scintillating means aligned behind the collimator means for capturing the collimated emanations and emitting scintillation photons corresponding thereto, comprising a two-dimensional array of scintillating fibers, wherein each scintillating fiber is located at a pre-selected x-position and y-position having x and y coordinates in an x-y plane; and

c) position encoding means for encoding the x-y position of an active scintillating fiber receiving a particle emanation within a pre-selected time interval, comprising photon detecting means for detecting the emitted scintillation photons and generating output signals correlatable therewith, optical coupling means for optically coupling each scintillating fiber to the photon detecting means in a manner which encodes the x-y coordinates of the scintillating fibers, and signal processing means for processing the output signals and generating position signals indicative of the encoded position of the active scintillating fiber.

2. The apparatus defined in claim 1, wherein the optical coupling means comprises a network of optical fibers.

3. The apparatus defined in claim 2, wherein the network of optical fibers comprises sets of position fibers optically coupled to each individual scintillating fiber representing the x and y coordinates of the position thereof.

4. The apparatus defined in claim 3, wherein the photon detecting means comprises banks of photon detectors, wherein each bank of photon detectors comprises a plurality of individual photon detectors.

5. The apparatus defined in claim 4, wherein the sets of position fibers comprise individual position fibers having input ends coupled to the scintillating fiber and output ends coupled to a pre-selected combination of individual photon detectors representing the coordinates of the position of the scintillating fiber.

6. The apparatus defined in claim 5, wherein each scintillating fiber has a front imaging face positioned to receive the collimated emanations and a rear emitting face for emitting the scintillation photons, and the input ends of the individual position fibers are coupled to the rear emitting face of the scintillating fibers.

7. The apparatus defined in claim 4, wherein the individual photon detectors comprise photomultiplier tubes.

8. The apparatus defined in claim 4, wherein the banks of photon detectors comprise an x-bank of photon detectors and a y-bank of photon detectors, and the sets of position fibers comprise sets of x-position fibers coupled to the x-bank of photon detectors and sets of y-position fibers coupled to the y-bank of photon detectors.

9. The apparatus defined in claim 8, wherein the position coordinates of each scintillating fiber are assigned a value expressed in a base having a pre-selected number of places, wherein each of the places has a range of values, and the individual position fibers represent the place and value of the position coordinates of the scintillating fiber.

10. The apparatus defined in claim 9, wherein the individual photon detectors are identified as if arranged in an array of rows and columns, and the individual detectors in each row of the array represent one of the pre-selected places of the position coordinates and the individual detectors in the columns of each row represent one of the value in the range of values for the coordinates.

11. The apparatus defined in claim 1, wherein the signal processing means comprises coincidence detection means for detecting when exactly one scintillating fiber emits scintillation photons within the pre-selected time interval.

12. The apparatus defined in claim 11, wherein the processing means comprises an electronic or computer processor comprising means for analyzing the output of the rows of individual photon detectors to determine the position of the active scintillating fiber.

13. The apparatus defined in claim 9, wherein the base is base 10.

14. The apparatus as defined in claim 13, wherein each bank of photon detectors comprises at least three rows of individual photon detectors, wherein each of the rows comprises ten individual detectors, and wherein the detectors in the first of the rows represents values from 0 to 9, the detectors in the second of the rows represents values from 00 to 90, and the detectors in the third of the rows represents values from 000 to 900.

15. The apparatus as defined in claim 14 comprising a fourth row of individual photon detectors, representing values from 0.0 to 0.9.

16. The apparatus defined in claim 10, wherein the base is base 2.

17. The apparatus defined in claim 1, wherein the scintillating fibers comprise an outer layer of conducting material and a thin conducting central electrode, the outer layer being capable of being negatively charged relative to the central electrode.

18. The apparatus defined in claim 1, wherein the scintillating fibers comprise a thin conducting central electrode capable of being positively charged relative to ground.

19. The apparatus defined in claim 1, wherein the particle emanations are gamma rays.

20. The apparatus defined in claim 1, wherein the scintillating fibers comprise an outer coating that gives off photons detectable by the photon detection means when excited by electrons.

21. The apparatus defined in claim 1, wherein the optical fibers not needed for position encoding are connected to the photon detection means for purposes of more complete detection of scintillation photons.

22. The apparatus defined in claim 1, wherein the scintillation means comprises a plate configured for holding the array of scintillating fibers.

23. The apparatus defined in claim 22, wherein the plate and position encoding means are manufactured in smaller units for later assembly into a larger assembly.

24. The apparatus defined in claim 4, wherein the individual photon detectors comprise large area array photodiodes.