US20030105397A1
Expired / Lapsed
US
⏱️ 0.0 years remaining
X-ray and gamma ray detector readout system
Assignee: Nova R&D Inc
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Filing: 2002-11-08
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Granted: —
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Expires: 2022-11-08
Abstract
Abstract A readout electronics scheme is under development for high resolution, compact PET (positron emission tomography) imagers based on LSO (lutetium ortho-oxysilicate, Lu 2 SiO 5 ) scintillator and avalanche photodiode (APD) arrays. The key is to obtain sufficient timing and energy resolution at a low power level, less than about 30 mW per channel, including all required functions. To this end, a simple leading edge level crossing discriminator is used, in combination with a transimpedance preamplifier. The APD used has a gain of order 1,000, and an output noise current of several pA/{square root}Hz, allowing bipolar technology to be used instead of CMOS, for increased speed and power efficiency. A prototype of the preamplifier and discriminator has been constructed, achieving timing resolution of 1.5 ns FWHM, 2.7 ns full width at one tenth maximum, relative to an LSO/PMT detector, and an energy resolution of 13.6% FWHM at 511 keV, while operating at a power level of 22 mW per channel. Work is in progress towards integration of this preamplifier and discriminator with appropriate coincidence logic and amplitude measurement circuits in an ASIC suitable for a high resolution compact PET instrument. The detector system and/or ASIC can also be used for many other applications for medical to industrial imaging.
Inventors
- 👤 Tumay Tumer
- 👤 Martin Clajus
- 👤 Gerard Visser
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 18:06
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/29; G01T1/2914; G01T1/2985; A; A61; A61B; A61B6/00; A61B6/02; A61B6/03; A61B6/037
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
124 words
1 . A method of imaging a portion of a human body, the method comprising the steps of: providing a radiopharmaceutical to said portion of said human body, said radiopharmaceutical producing gamma ray photons; positioning a detection system proximate to said portion of said human body, wherein said detection system is comprised of a detector, wherein said detector comprised of two dimensional arrays of plurality of detectors arranged in groups; determining a direction and an energy for a portion of said gamma ray photons entering said detection system; processing said direction and energy data for said portion of gamma ray photons; and displaying an image of said portion of said human body, wherein said image is based on said processed direction and energy data.
Claim 2
Dependent Claim
124 words
1 . A method of imaging a portion of a human body, the method comprising the steps of: providing a radiopharmaceutical to said portion of said human body, said radiopharmaceutical producing gamma ray photons; positioning a detection system proximate to said portion of said human body, wherein said detection system is comprised of a detector, wherein said detector comprised of two dimensional arrays of plurality of detectors arranged in groups; determining a direction and an energy for a portion of said gamma ray photons entering said detection system; processing said direction and energy data for said portion of gamma ray photons; and displaying an image of said portion of said human body, wherein said image is based on said processed direction and energy data.
Claim 3
Dependent Claim
18 words
2 . The method of claim 1 , wherein said portion of said human body is an organ.
Claim 4
Dependent Claim
18 words
3 . The method of claim 1 , wherein said portion of said human body is a breast.
Claim 5
Dependent Claim
28 words
4 . The method of claim 1 , wherein said image can be used to determine the position of a lesion which can be located from the image.
Claim 6
Dependent Claim
17 words
5 . The method of claim 1 , wherein gamma rays from annihilation of positrons are detected.
Claim 7
Dependent Claim
38 words
6 . The method of claim 5 , wherein the annihilation gamma rays are detected in coincidence with two detectors and the direction of the gamma rays are determined by calculating the chord that connects the two detectors.
Claim 8
Dependent Claim
22 words
7 . The method of claim 1 , wherein said imaging method can be used to develop compact a portable imaging instrument.
Claim 9
Dependent Claim
26 words
8 . The method of claim 1 , wherein said imaging method uses a collimator for determining the direction of the photons that enter its aperture.
Claim 10
Dependent Claim
115 words
9 . A medical imaging system for imaging a portion of a living organism, said portion treated with a radiopharmaceutical, said radiopharmaceutical emitting positrons which annihilate and produce two gamma rays, comprising: a detector comprised of a plurality of two-dimensional detector crystals, wherein an entrance aperture of said detector is external to said living organism and proximate to said portion of said living organism, wherein emitted gamma ray photons pass into said detector; a multi channel readout system coupled to said plurality of detectors; a processor coupled to said multi-channel readout system; and a monitor coupled to said processor, said monitor displaying an image of photons coming from the said portion of said living organism.
Claim 11
Dependent Claim
115 words
9 . A medical imaging system for imaging a portion of a living organism, said portion treated with a radiopharmaceutical, said radiopharmaceutical emitting positrons which annihilate and produce two gamma rays, comprising: a detector comprised of a plurality of two-dimensional detector crystals, wherein an entrance aperture of said detector is external to said living organism and proximate to said portion of said living organism, wherein emitted gamma ray photons pass into said detector; a multi channel readout system coupled to said plurality of detectors; a processor coupled to said multi-channel readout system; and a monitor coupled to said processor, said monitor displaying an image of photons coming from the said portion of said living organism.
Claim 12
Dependent Claim
26 words
10 . The medical imaging system of claim 9 , wherein a portion of said emitted gamma ray photons undergo a photoelectric absorption in the detector.
Claim 13
Dependent Claim
34 words
11 . The medical imaging system of claim 9 , further comprising a collimator to restrict the angle of the gamma rays incident on the said system to determine the direction of the photons.
Claim 14
Dependent Claim
25 words
12 . The medical imaging system of claim 9 , further comprising of detectors on opposite sides of the said portion of a living organism.
Claim 15
Dependent Claim
22 words
13 . The medical imaging system of claim 9 , further comprising of detectors surrounding the said portion of a living organism.
Claim 16
Dependent Claim
20 words
14 . The medical imaging system of claim 9 , further comprising of septas placed inside or around the detectors.
Claim 17
Dependent Claim
24 words
15 . The medical imaging system of claim 9 , further comprising several rings of detectors surrounding the said portion of the living organism.
Claim 18
Dependent Claim
25 words
16 . The medical imaging system of claim 9 , further comprising depth of interaction determination of the incident gamma ray inside each detector element.
Claim 19
Dependent Claim
42 words
17 . The medical imaging system of claim 9 , further comprising depth of interaction determination of the incident gamma ray inside each detector element, which is used to eliminate radial elongation error in calculating the direction of the incident gamma rays.
Claim 20
Dependent Claim
34 words
18 . The medical imaging system of claim 9 , further comprising energy determination of the gamma ray, which is used to discriminate gamma rays scattered inside the said portion of the living organism.
Claim 21
Dependent Claim
24 words
19 . The medical imaging system of claim 9 , further comprising of an integrated circuit which readout the signals from the detector arrays.
Claim 22
Dependent Claim
24 words
20 . The medical imaging system of claim 19 , wherein the said integrated circuit includes fast constant fraction discriminators integrated on the circuit.
References Cited (Backward Citations)
US4864140A
Cited
US5138165A
Cited
US5396187A
Cited
US5451789A
Cited
US5786597A
Cited
US5719400A
Cited
US5821541A
Cited
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