US3683185A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Radiation imaging apparatus
Assignee: Nuclear Chicago Corp
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Filing: 1969-08-08
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Granted: 1972-08-08
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Expires: 1989-08-08
Abstract
Abstract An image intensifier type of gamma ray scintillation camera employing a relatively thick scintillation crystal at the input end for good efficiency in converting gamma rays into scintillations and a fast, position sensitive photodiode with computer circuitry at the output end for producing coordinate electrical signals representing the centroid of the relatively large light spot striking the photodiode. Pulse height analysis is performed on the total sum signal from the photodiode to reject unwanted events manifested at the output of the photodiode, and appropriate ratio computing circuitry is employed to maintain a constant image size over a range of intensities of light spots striking the photodiode.
Inventors
- 👤 Gerd Muehllehner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:03
CPC Classifications
H; H01; H01J; H01J31/00; H01J31/08; H01J31/50; H01J31/508; G; G01; G01T; G01T1/00; G01T1/16; G01T1/161; G01T1/164; G01T1/1641; G01T1/1645; H01J31/49; A; A61; A61B; A61B6/00; A61B6/42; A61B6/4208; A61B6/4258
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
204 words
In combination in a gamma ray camera: an image intensifier system, including an input photocathode on an inside surface of a curved entrance window of said system and an output phosphor screen, operative in response to an input light distribution on said photocathode to produce an intensified version of said distribution on said screen; a crystal assembly comprising a scintillation crystal in the form of a flat continuous disc and a glass cove in the form of a flat disc mounted on said crystal; a light pipe comprising a plurality of glass rods coupling said flat glass cover of said crystal assembly to said curved entrance window of said intensifier system so that a gamma ray interacting with said crystal produces a light flash which results in a light spot on said photocathode and a corresponding intensified version of said light spot on said screen, the centroid of said light spot on said photocathode being at the spatial coordinates of the point of interaction of said gamma ray with said crystal; and a position sensitive photodiode coupled to said output phosphor screen to produce output electrical signals representing said spatial coordinates and the amount of energy deposited in said crystal by said gamma ray.
Claim 2
Dependent Claim
204 words
In combination in a gamma ray camera: an image intensifier system, including an input photocathode on an inside surface of a curved entrance window of said system and an output phosphor screen, operative in response to an input light distribution on said photocathode to produce an intensified version of said distribution on said screen; a crystal assembly comprising a scintillation crystal in the form of a flat continuous disc and a glass cove in the form of a flat disc mounted on said crystal; a light pipe comprising a plurality of glass rods coupling said flat glass cover of said crystal assembly to said curved entrance window of said intensifier system so that a gamma ray interacting with said crystal produces a light flash which results in a light spot on said photocathode and a corresponding intensified version of said light spot on said screen, the centroid of said light spot on said photocathode being at the spatial coordinates of the point of interaction of said gamma ray with said crystal; and a position sensitive photodiode coupled to said output phosphor screen to produce output electrical signals representing said spatial coordinates and the amount of energy deposited in said crystal by said gamma ray.
Claim 3
Dependent Claim
174 words
Apparatus as claimed in claim 1, wherein said output signals from said photodiode comprise first and second pairs of signals, said first pair representing (x+) and (x-) coordinate information and said second pair representing (y+) and (y-) coordinate information, and the sum of said first and second pairs of signals representing said amount of energy; and further comprising: first and second circuit means receiving said first and second pairs of signals, respectively, for producing X and Y coordinate signals in accordance with the following equations: third circuit means receiving said first and second pairs of signals for producing a Z signal in accordance with the following equation: Z (x+) + (x-) + (y+) + (y-); a pulse height analyzer receiving said Z signal for producing a trigger signal when the magnitude of said Z signal corresponds to a gamma interaction in a selected energy band; and a cathode ray tube for displaying a light spot in a position signaled by said X and Y signals when said tube is triggered by said trigger signal.
Claim 4
Dependent Claim
172 words
Apparatus as claimed in claim 1, wherein said output signals from said photodiode comprise first and second pairs of signals, said first pair representing (x+) and (x-) coordinate information and said second pair representing (y+) and (y-) coordinate information, and the sum of said first and second pairs of signals representing said amount of energy; and further comprising: first circuit means for summing said first and second pairs of signals to produce a Z signal representing said amount of energy; second and third circuit means receiving said first and second pairs of signals, respectively, and each receiving said Z signal for producing X and Y coordinate signals in accordance with the following equations: a pulse height analyzer receiving said Z signal for producing a trigger signal when the magnitude of said Z signal corresponds to a gamma interaction in a selected energy band; and a cathode ray tube for displaying a light spot in a position signalled by said X and Y signals when said tube is triggered by said trigger signal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-08 | 1976-02-07 | 1976-08-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-08 | 1980-02-07 | 1980-08-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-08 | 1984-02-07 | 1984-08-08 | $7700.00 | Window Closed / Lapsed |