Patent US2845617A successfully refreshed from Google Patents.
US3732419A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Scintillation camera with improved resolution
Assignee: Nuclear Chicago Corp
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Filing: 1970-10-12
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Granted: 1973-05-08
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Expires: 1990-10-12
Abstract
Abstract An Anger-type scintillation camera employing a threshold preamplifier at the output of each photomultiplier tube to eliminate the contribution of tubes distant from the location of each scintillation to the coordinate position signal, thereby improving the intrinsic resolution of the Anger-type detector.
Inventors
- 👤 G Kulberg
- 👤 G Muehllehner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 14:26
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/16; G01T1/161; G01T1/164; G01T1/1641; G01T1/1642; A; A61; A61B; A61B6/00; A61B6/42; A61B6/4208; A61B6/4258
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
154 words
Radiation imaging apparatus comprising a scintillating crystal and a bank of photomultiplier tubes viewing overlapping areas of said crystal, said crystal being in the form of a flat disc having a longest dimension at leasT as great as twice the diameter of said photomultiplier tubes, and at least three photomultiplier tubes being disposed along said longest dimension; and computing circuitry coupled to said photomultiplier tubes to compute the coordinates of a scintillation produced in said crystal by the interaction therewith of a quantum of radiation, including circuit means at the output of each photomultiplier tube for amplifying output signals from each photomultiplier tube in a non-linear fashion, characterized in that larger output signals receive greater amplification than smaller output signals, thereby enhancing the relatively accurate signal information contributed by photomultiplier tubes near each scintillation over the relatively inaccurate signal information contributed by distant photomultiplier tubes to improve the overall spatial resolution of said apparatus.
Claim 2
Dependent Claim
154 words
Radiation imaging apparatus comprising a scintillating crystal and a bank of photomultiplier tubes viewing overlapping areas of said crystal, said crystal being in the form of a flat disc having a longest dimension at leasT as great as twice the diameter of said photomultiplier tubes, and at least three photomultiplier tubes being disposed along said longest dimension; and computing circuitry coupled to said photomultiplier tubes to compute the coordinates of a scintillation produced in said crystal by the interaction therewith of a quantum of radiation, including circuit means at the output of each photomultiplier tube for amplifying output signals from each photomultiplier tube in a non-linear fashion, characterized in that larger output signals receive greater amplification than smaller output signals, thereby enhancing the relatively accurate signal information contributed by photomultiplier tubes near each scintillation over the relatively inaccurate signal information contributed by distant photomultiplier tubes to improve the overall spatial resolution of said apparatus.
Claim 3
Dependent Claim
70 words
Apparatus as claimed in claim 1, wherein said circuit means comprises a threshold preamplifier circuit having an input-output transfer characteristic such that input signals of a magnitude smaller than a preselected threshold magnitude produce substantially no output signal and input signals of a magnitude greater than said preselected threshold magnitude produce an amplified output signal which is substantially proportional to the magnitude of the input signal above said threshold magnitude.
Claim 4
Dependent Claim
35 words
Apparatus as claimed in claim 2, wherein said threshold preamplifier circuit comprises a wide band amplifier stage, a threshold amplifier stage having a preselected threshold magnitude, an integration circuit stage, and an output amplifier stage.
Claim 5
Dependent Claim
114 words
Apparatus as claimed in claim 1, wherein said scintillating crystal comprises a flat round disc having a diameter of at least 6 inches; said bank of photomultiplier tubes comprises at least seven photomultiplier tubes of substantially 3-inch diameter arranged in a hexagonal array with one central tube and six peripheral tubes; and said circuit means comprises a threshold preamplifier circuit having an input-output transfer characteristic such that input signals of a magnitude smaller than a preselected threshold magnitude produce substantially no output signal and input signals of a magnitude greater than said preselected threshold magnitude produce an amplified output signal which is proportional to the magnitude of the input signal above said threshold magnitude.
Claim 6
Dependent Claim
102 words
Apparatus as claimed in claim 1, wherein said scintillating crystal comprises a flat round disc having a diameter of at least 10 inches; said bank of photomultiplier tubes comprises at least 19 photomultiplier tubes arranged in a hexagonal array with a central tube, a first hexagonal arrangement of six tubes surrounding said central tube and a second hexagonal arrangement of twelve tubes surrounding said first hexagonal arrangement, and said circuit means comprises a threshold preamplifier circuit having an input-output transfer characteristic such that photomultiplier tubes remote from the location of a scintillation substantially do not contribute signal information to said computing circuitry.
Claim 7
Dependent Claim
36 words
Apparatus as claimed in claim 5, wherein said threshold preamplifier has a threshold magnitude equal to about 5 percent of the maximum expected output signal from a photomultiplier tube directly above a scintillation in said crystal.
Claim 8
Dependent Claim
130 words
Radiation imaging apparatus comprising a flat round disc of scintillating crystal having a diameter of at least 6 inches; a bank of photomultiplier tubes comprising at least seven tubes arranged in a hexagonal array and viewing overlapping areas of said crystal; a plurality of threshold preamplifier circuits, one each coupled to the output of each said photomultiplier tube and having an input-output transfer characteristic such that input signals of a magnitude smaller than a preselected threshold magnitude produce substantially no output signal and input signals of a magnitude greater than said preselected threshold magnitude produce An amplified output signal proportional to the magnitude of the input signal above said threshold magnitude; and circuit means coupled to said preamplifier circuits for computing the position coordinates of a scintillation in said crystal.
Claim 9
Dependent Claim
130 words
Radiation imaging apparatus comprising a flat round disc of scintillating crystal having a diameter of at least 6 inches; a bank of photomultiplier tubes comprising at least seven tubes arranged in a hexagonal array and viewing overlapping areas of said crystal; a plurality of threshold preamplifier circuits, one each coupled to the output of each said photomultiplier tube and having an input-output transfer characteristic such that input signals of a magnitude smaller than a preselected threshold magnitude produce substantially no output signal and input signals of a magnitude greater than said preselected threshold magnitude produce An amplified output signal proportional to the magnitude of the input signal above said threshold magnitude; and circuit means coupled to said preamplifier circuits for computing the position coordinates of a scintillation in said crystal.
Claim 10
Dependent Claim
61 words
Apparatus as claimed in claim 7, wherein said crystal has a diameter of at least 10 inches; said bank of photomultiplier tubes comprises at least 19 tubes arranged in a hexagonal array; and said threshold magnitude is selected such that photomultiplier tubes having central axes two phototube diameters from said scintillation substantially do not contribute signal information to said circuit means.
Claim 11
Dependent Claim
62 words
Apparatus as claimed in claim 7, wherein said crystal has a diameter of at least 10 inches; said bank of photomultiplier tubes comprises at least 19 tubes arranged in a hexagonal array; and said threshold magnitude is selected to be equal to about 5 percent of the maximum expected output signal from a photomultiplier tube directly above a scintillation in said crystal.
Claim 12
Dependent Claim
89 words
An Anger-type scintillation camera having a scintillating crystal and a bank of photomultiplier tubes viewing overlapping areas of said crystal and coordinate computing circuitry coupled to said photomultiplier tubes, wherein the improvement comprises a plurality of non-linear preamplification means each coupled to a corresponding photomultiplier tube for amplifying large signals from said corresponding photomultiplier tube a greater amount than small signals therefrom to enhance substantially the information contribution from photomultiplier tubes near each scintillation over that from distant photomultiplier tubes, thereby to improve the spatial resolution of said camera.
Claim 13
Dependent Claim
89 words
An Anger-type scintillation camera having a scintillating crystal and a bank of photomultiplier tubes viewing overlapping areas of said crystal and coordinate computing circuitry coupled to said photomultiplier tubes, wherein the improvement comprises a plurality of non-linear preamplification means each coupled to a corresponding photomultiplier tube for amplifying large signals from said corresponding photomultiplier tube a greater amount than small signals therefrom to enhance substantially the information contribution from photomultiplier tubes near each scintillation over that from distant photomultiplier tubes, thereby to improve the spatial resolution of said camera.
Claim 14
Dependent Claim
68 words
Apparatus as claimed in claim 10, wherein said non-linear preamplification means comprises a threshold preamplifier circuit having an input-output transfer characteristic such that input signals of a magnitude smaller than a preselected threshold magnitude produce substantially no output signal and input signals of a magnitude greater than said preselected threshold magnitude produce an amplified output signal proportional to the magnitude of the input signal above said threshold magnitude.
Claim 15
Dependent Claim
37 words
Apparatus as claimed in claim 11, wherein said threshold magnitude is selected such that photomultiplier tubes having central axes two phototube diameters or more distant from a scintillation substantially do not contribute to the coordinate signal information.
Claim 16
Dependent Claim
36 words
Apparatus as claimed in claim 11, wherein said threshold magnitude is selected to be equal to about 5 percent of the maximum expected output signal from a photomultiplier tube directly above a scintillation in said crystal.
References Cited (Backward Citations)
US3011057A
Cited
US3509341A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-05-07 | 1976-11-06 | 1977-05-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-07 | 1980-11-06 | 1981-05-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-07 | 1984-11-06 | 1985-05-08 | $7700.00 | Window Closed / Lapsed |