Patent US3207847A successfully refreshed from Google Patents.
Patent US4419585A successfully refreshed from Google Patents.
US4419585A
Expired / Lapsed
US
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Variable angle slant hole collimator
Assignee: General Hospital Corp
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Filing: 1981-02-26
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Granted: 1983-12-06
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Expires: 2001-02-26
Abstract
Abstract A variable angle radiation collimator particularly for use in gamma-photon medical diagnostic systems in a gamma-photon camera system for radiological examination of human subjects. The collimator provides collimation of gamma-photon radiation along a single beam direction which may be varied along two axes to adjust exposure angle or to provide a scanning capability. The collimator is a stack of substantially identical radiation-opaque plates, each of which are apertured with a similar array of openings. The combined effect of the stacked aperture plates is to transmit radiation in a predetermined orientation. The collimated angle of the radiation thus generated is controlled by the coincidence of the array of openings. The stack is retained by a mechanism which permits adjustment of the collimation angle, and the plates are fabricated to provide ease of shear motion during such adjustment. In addition, the tradeoff between the resolution and intensity of radiation transmitted may be easily varied by adjusting stack thickness.
Inventors
- 👤 H. William Strauss
- 👤 Richard H. Moore
- 👤 Nathaniel M. Alpert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 11:52
CPC Classifications
G; G21; G21K; G21K1/00; G21K1/02; G21K1/025; G02; G02B; G02B5/00; G02B5/005; A; A61; A61B; A61B6/00; A61B6/02; A61B6/03; A61B6/037; A61B6/42; A61B6/4291
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
137 words
A radiation collimator comprising: a plurality of sheets of a generally radiation absorbing material, said sheets being apertured in a predetermined two dimensional pattern over a substantial area of said sheets; and means for stacking said sheets with said apertures in alignment to provide a set of radiation channels through the stack of sheets with a predetermined orientation and to provide for angular variation in said predetermined orientation by skewing of said sheets within said stack; said set of radiation channels forming a collimated view through said sheets defined by said predetermined orientation; the pattern of apertures in each sheet being selected relative to the pattern of apertures in adjacent sheets of said stack to provide said predetermined orientation to the set of radiation channels with a characteristic within the range of characteristics from divergence to convergence.
Claim 2
Dependent Claim
137 words
A radiation collimator comprising: a plurality of sheets of a generally radiation absorbing material, said sheets being apertured in a predetermined two dimensional pattern over a substantial area of said sheets; and means for stacking said sheets with said apertures in alignment to provide a set of radiation channels through the stack of sheets with a predetermined orientation and to provide for angular variation in said predetermined orientation by skewing of said sheets within said stack; said set of radiation channels forming a collimated view through said sheets defined by said predetermined orientation; the pattern of apertures in each sheet being selected relative to the pattern of apertures in adjacent sheets of said stack to provide said predetermined orientation to the set of radiation channels with a characteristic within the range of characteristics from divergence to convergence.
Claim 3
Dependent Claim
12 words
The collimator of claim 1 wherein said sheets are fabricated of tungsten.
Claim 4
Dependent Claim
17 words
The collimator of claim 1 or 2 wherein said sheets have a thickness of approximately 0.25 mm.
Claim 5
Dependent Claim
12 words
The collimator of claim 1 wherein said sheets include a lead coating.
Claim 6
Dependent Claim
18 words
The collimator of claim 4 wherein said sheets include a stainless steel support mesh for said lead coating.
Claim 7
Dependent Claim
38 words
The collimator of claim 1 wherein each of said sheets in said stack of sheets includes a peripheral portion of increased thickness whereby said sheets as stacked are supported with their central portions physically separated from each other.
Claim 8
Dependent Claim
23 words
The collimator of claim 1 wherein said sheets include a peripheral notch with the sheets as stacked having said notches in predetermined alignment.
Claim 9
Dependent Claim
23 words
The collimator of claim 7 further including means for engaging said notches in the sheets as stacked to provide registration and alignment control.
Claim 10
Dependent Claim
13 words
The collimator of claim 1 wherein said apertures are approximately 2 mm square.
Claim 11
Dependent Claim
24 words
The collimator of claim 1 wherein said stacking means is adapted for holding a variable number of said sheets in the stack of sheets.
Claim 12
Dependent Claim
22 words
The collimator of claim 1 wherein each said sheet comprises stainless steel having a plating thereon of a higher radiation absorbing material.
Claim 13
Dependent Claim
13 words
The collimator of claim 11 wherein said plating is a lead tin alloy.
Claim 14
Dependent Claim
16 words
The collimator of claim 1 wherein said apertures are filled with a low radiation absorbing material.
Claim 15
Independent Claim
132 words
A method for making radiation exposures of a subject under study through a collimator consisting of a set of sheets apertured in a two dimensional pattern and stacked with the apertures in alignment to provide a set of radiation channels through the stack with a predetermined orientation to the collimation thereby produced, the method comprising the steps of: rotating said collimator about a desired tomographic viewing axis of a subject under study; varying said predetermined orientation by skewing the stack of sheets during the rotation of said collimator; the pattern of apertures in each sheet being selected relative to the pattern of apertures in adjacent sheets of said stack to provide said predetermined orientation to the set of radiation channels with a characteristic within the range of characteristics from divergence to convergence.
Claim 16
Independent Claim
132 words
A method for making radiation exposures of a subject under study through a collimator consisting of a set of sheets apertured in a two dimensional pattern and stacked with the apertures in alignment to provide a set of radiation channels through the stack with a predetermined orientation to the collimation thereby produced, the method comprising the steps of: rotating said collimator about a desired tomographic viewing axis of a subject under study; varying said predetermined orientation by skewing the stack of sheets during the rotation of said collimator; the pattern of apertures in each sheet being selected relative to the pattern of apertures in adjacent sheets of said stack to provide said predetermined orientation to the set of radiation channels with a characteristic within the range of characteristics from divergence to convergence.
Claim 17
Dependent Claim
14 words
The method of claim 14 wherein said varying step includes continuous variations of orientation.
Claim 18
Dependent Claim
14 words
The method of claim 14 wherein said varying step includes step variations of orientation.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-12-05 | 1987-06-06 | 1987-12-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-12-05 | 1991-06-06 | 1991-12-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-12-05 | 1995-06-06 | 1995-12-06 | $7700.00 | Window Closed / Lapsed |