Detector systems for integrated radiation imaging

• US 10,663,606 B2
• Filed: 02/28/2019
• Issued: 05/26/2020
• Est. Priority Date: 05/31/2012
• Status: Active Grant

• Current Assignee: Minnesota Imaging and Engineering LLC
• Original Assignee: Minnesota Imaging and Engineering LLC
• Inventors: Nelson, Robert Sigurd, Nelson, William Bert
• Primary Examiner(s): Kim, Christine S.
• Application Number:
  US16/289,281
• Publication Number:
  US 20190204460A1
• Time in Patent Office: 453 Days
• CPC Class Codes: B82Y 15/00 Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
• CPC Class Codes: G01T 1/1611 using both transmission and emission sources sequentially SPECT imaging G01T1/1642; PET imaging G01T1/2985; detecting prohibited goods, e.g. weapons, explosives, hazardous substances, contraband or smuggled objects G01V5/20
• CPC Class Codes: G01T 1/247 Detector read-out circuitry for processing gain or off-set correction H04N

Abstract

Detector systems for enhanced radiographic imaging incorporate Compton and PET imaging capabilities. The detector designs employ one or more layers of detector modules comprised of edge-on or face-on detectors, or a combination of edge-on and face-on detectors, which may employ structured detectors. The detectors implement tracking capabilities and operate in a non-coincidence or coincidence detection mode.

Claims

1. A detector system for integrated Compton-PET radiation imaging, comprising:

an x-ray and gamma ray radiation detector having one or more detector layers comprised of detector modules configured to generate readout signals based on interactions of x-ray photons from an x-ray radiation source and gamma ray photons from a gamma ray radiation source, wherein at least one layer of the detector modules includes at least one of an edge-on detector module, a structured detector module, or a 3D spatial resolution detector module;

electronics configured for tracking the interactions of at least one of the x-ray photons or the gamma ray photons and analyzing the readout signals using at least one of energy integration or photon counting or photon counting with energy resolution techniques; and

an electronic communications link to a computer configured for post-processing, storage, and display of radiation image data generated thereby.

2. The detector system of claim 1, wherein the detector modules provide at least one of block, 1D, 2D or 3D spatial resolution, energy resolution or temporal resolution.

3. The detector system of claim 1, wherein the detector modules comprise a combination of edge-on and face-on detectors.

4. The detector system of claim 3, wherein:

the edge-on detectors incorporate sub-aperture-resolution capabilities that enhance detector spatial resolution using sub-aperture resolution (SAR) readout techniques with edge-on, side-irradiation detector geometry to estimate an interaction location of an event in the edge-on, side irradiation detector geometry;

or

the face-on detectors incorporate depth-of-interaction capabilities to estimate the interaction location.

5. The detector system of claim 1, wherein the detector modules provide temporal resolution adapted for time-of-flight PET coincidence imaging.

6. The detector system of claim 1, wherein:

one or more of the detector modules have pixel sizes that are non-uniform in an axial direction, wherein a high resolution pixel size is implemented near a center of the detector system in the axial direction with lower resolution pixel size on both sides of the center;

or

one or more of the detector modules have a pixel size that is synthesized, wherein outputs of two or more pixels in the axial direction are combined electronically to synthesize a desired distribution of pixel sizes in the axial direction.

7. The detector system of claim 1, wherein the electronics comprise readout ASICs of varying performance deployed as a function of detector depth along pixel columns in the detector modules, wherein readout ASICs of progressively slower speeds read out pixels at progressively greater detector depths.

8. The detector system of claim 1, wherein the electronics are configured for:

tracking gamma ray interactions within and between two or more layers of the detector modules; and

coincidence detection of the gamma ray interactions between a pair of such detector systems positioned on opposite sides of an object to be imaged.

9. The detector system of claim 1, wherein the electronics comprise shielded readout ASICs mounted within an etched region along a bottom edge of a semiconductor detector substrate of the detector modules.

10. The detector system of claim 1, further comprising a nuclear collimator positioned between the detector modules and an object being imaged thereby, and wherein the detector system is configured for 3D imaging.

11. The detector system of claim 1, wherein individual modules of the detector modules are configured for at least one of x-ray or gamma ray photon counting, photon counting with energy resolution, energy integrating, or x-ray or gamma ray photon interaction tracking.

12. The detector system of claim 1, wherein one or more of the detector modules comprise structured gas-filled straw detectors with low-Z or moderate-Z annuli material selected to enhance Compton scatter.

13. The detector system of claim 1, wherein one or more of the layers of detector modules comprise edge-on detectors irradiated from a side and having a substrate positioned edge-on to at least one of x-rays or gamma rays incident thereon.

14. The detector system of claim 13, wherein the detector system is configured as a Compton-PET imaging system adapted to function as a SPECT imaging system or SPECT camera, or implemented with a hand-held detector probe adapted to function as a gamma camera.

15. The detector system of claim 1, wherein the x-ray and gamma ray radiation detector comprises two or more layers of the detector modules, or one or more layers of multilayer detector modules.

16. A detector system for integrated Compton-PET radiation imaging, the detector system comprising:

an x-ray and gamma ray radiation detector having one or more detector layers comprised of detector modules configured to generate readout signals based on interactions of x-ray photons from an x-ray radiation source and gamma ray photons from a gamma ray radiation source, wherein at least one layer of the detector modules includes at least one of an edge-on detector module, a structured detector module, or a 3D spatial resolution detector module;

electronics configured for tracking the interactions of at least one of the x-ray photons or the gamma ray photons and analyzing the readout signals using at least one of energy integration or photon counting or photon counting with energy resolution techniques; and

an electronic communications link to a computer configured for post-processing, storage, and display of radiation image data generated thereby;

wherein one or more of the layers of detector modules comprise edge-on detector modules irradiated from a side and having a substrate positioned edge-on to at least one of the x-ray photons or the gamma ray photons incident thereon.

17. The detector system of claim 16, wherein:

the edge-on detector modules are configured in a focused structure geometry comprising a focused planar, focused ring, or focused partial ring detector format, or tilted with respect to adjacent edge-on detector modules to achieve a focusing effect;

or

the edge-on detector modules have gaps between adjacent detector modules and the gaps are in an upper detector layer effectively filled by offset detector modules in adjacent lower detector layers.

18. The detector system of claim 16, wherein the edge-on detector modules include at least one of a structured gas-filled straw detector, a scintillator-photodetector, a structured quantum dot radiation detector, a structured semiconductor nanoparticle radiation detector, a structured low temperature dielectric medium detector, or a structured 3D semiconductor detectors.

19. The detector system of claim 16, wherein at least some of the edge-on detector modules have an angled pixel structure with focused geometry relative to the radiation source.

20. The detector system of claim 16, wherein the detector modules have non-uniform geometry, and wherein the edge-on detector modules are positioned at a middle of a detector arc that images a region of interest within an object, with face-on detectors on either side of the detector arc.

21. The detector system of claim 16, wherein one or more of the edge-on detector modules comprises a relatively lower-Z quantum dot or nanoparticle material positioned adjacent a radiation entrance surface and a relatively higher-Z quantum dot or nanoparticle material positioned farther from the radiation entrance surface than the relatively lower-Z material.

22. An integrated CT-Compton-PET detector imaging system comprising:

one or more detector layers comprised of edge-on detector modules irradiated from a side and having a substrate positioned edge-on to at least one of x-ray photons from an x-ray radiation source or gamma ray photons from a gamma ray radiation source, incident thereon;

electronics configured for tracking interactions of the x-ray photons and the gamma ray photons and analyzing the readout signals using at least one of energy integration or photon counting or photon counting with energy resolution techniques; and

an electronic communications link to a computer configured for post-processing, storage, and display of radiation image data generated thereby;

wherein the detector imaging system is configured as a CT detector imaging system and a Compton-PET detector imaging system configured to function independently, with the Compton-PET detector imaging system having one or more of the detector layers comprised of the edge-on detector modules, and the CT detector imaging system having one or more of the detector layers comprised of the edge-on detector modules, and

one or more of the x-ray or gamma ray sources adapted to implement multispectral imaging.

23. The imaging system of claim 22, wherein the one or more x-ray or gamma ray sources comprise multiple carbon nanotube or scanning electron beam sources adapted for at least one of reducing image acquisition time or implementing multispectral imaging.

24. The imaging system of claim 22, wherein the CT-Compton-PET detector imaging system is adapted to function as a SPECT camera.

25. The imaging system of claim 22, wherein the one or more layers of edge-on detector modules comprise multilayer detector modules irradiated from the side and having the substrate positioned edge-on to at least one of the x-ray photons from the x-ray radiation source or the gamma ray photons from the gamma ray radiation source.

26. The imaging system of claim 25, comprising two or more layers of the edge-on detector modules, wherein the CT detector imaging system comprises at least a first layer of the edge-on detector modules and the Compton-PET detector imaging system comprises at least a second layer of the edge-on detector modules or a layer of face-on detector modules.