Patent US5137998A successfully refreshed from Google Patents.
Patent US4047037A successfully refreshed from Google Patents.
US4047037A
Expired / Lapsed
US
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Gamma ray camera for nuclear medicine
Assignee: The Ohio State University
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Filing: 1976-02-09
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Granted: 1977-09-06
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Expires: 1996-02-09
Abstract
Abstract An improved gamma camera arrangement wherein the spatially defined acceptance of gamma radiation from a source distribution of clinical interest is enhanced by a unique collimator structure. Aliasing frequencies otherwise derived from an orthogonal strip detector array are identified and avoided through a structural geometry wherein collimator resolution is greater than or equal to about 1.7(l), where, l, is the strip spacing of the array.
Inventors
- 👤 Philip A. Schlosser
- 👤 John W. Steidley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 08:31
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/29; G01T1/2914; G01T1/2921; G01T1/2928; A; A61; A61B; A61B6/00; A61B6/42; A61B6/4208; A61B6/4258; G01T1/16; G01T1/161; G01T1/164; G01T1/1641; G01T1/1642
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
228 words
In a gamma camera type device for deriving image defining information of the source distribution of gamma rays providing a photon energy level, E, of interest, said device including an orthogonal strip array semi-conductor for deriving spatial and energy level information corresponding with said distribution, said detector array of strips having a frequency vs and strip spacing, l, said device further including collimator means operatively associated with said detector and having an inwardly disposed plane defining side spaced from the midplane of said detector a distance, C, having an outwardly disposed plane defining side spaced from said inward side to define a thickness, A, and spaced from said source a distance, B; the improvement wherein said collimator means comprises: an array of adjacently disposed channels, having internal surfaces and disposed intermediate of said inward and outward sides, said array being configured to define a septal thickness, T, intermediate said channels, an effective collimator thickness, A E = A - [2/μ(E)], and μ (E) is the attenuation coefficient of the surface defining material of said channels, for said energy level, E, said channels having a channel cross sectional area of effective diameter, D; and said collimator means having a collimator resolution, R c , equal to or greater than about 1.7 (l) and being configured in substantial satisfaction of the expression: R.sub.c = (D/A.sub.E) (A + B + C).
Claim 2
Dependent Claim
228 words
In a gamma camera type device for deriving image defining information of the source distribution of gamma rays providing a photon energy level, E, of interest, said device including an orthogonal strip array semi-conductor for deriving spatial and energy level information corresponding with said distribution, said detector array of strips having a frequency vs and strip spacing, l, said device further including collimator means operatively associated with said detector and having an inwardly disposed plane defining side spaced from the midplane of said detector a distance, C, having an outwardly disposed plane defining side spaced from said inward side to define a thickness, A, and spaced from said source a distance, B; the improvement wherein said collimator means comprises: an array of adjacently disposed channels, having internal surfaces and disposed intermediate of said inward and outward sides, said array being configured to define a septal thickness, T, intermediate said channels, an effective collimator thickness, A E = A - [2/μ(E)], and μ (E) is the attenuation coefficient of the surface defining material of said channels, for said energy level, E, said channels having a channel cross sectional area of effective diameter, D; and said collimator means having a collimator resolution, R c , equal to or greater than about 1.7 (l) and being configured in substantial satisfaction of the expression: R.sub.c = (D/A.sub.E) (A + B + C).
Claim 3
Dependent Claim
30 words
The improved gamma camera device of claim 1 wherein said internal surface of said array of adjacently disposed channels are configured as channel sides defining a square internal channel cross-section.
Claim 4
Dependent Claim
60 words
The improved gamma camera device of claim 2 wherein said array of channels comprises a plurality of sheet members of height, h, each configured having a plurality of mutually equally spaced, parallel slots of length equal to or about, h/2, and of width, w; said members being mutually internested along said slots to define said array of adjacently disposed channels.
Claim 5
Dependent Claim
35 words
The improved gamma camera device of claim 3 wherein said sheet members have a thickness equal to said septal wall thickness, T, and said height, h, is substantially equal to said collimator means thickness, A.
Claim 6
Dependent Claim
38 words
The improved gamma camera device of claim 4 wherein said sheet members are formed of said side defining material, said material exhibiting a said attenuation coefficient μ (E) for a said energy level, E, of about 140 keV.
Claim 7
Dependent Claim
16 words
The improved gamma camera device of claim 4 wherein said sheet members are formed of tungsten.
Claim 8
Dependent Claim
32 words
The improved gamma camera device of claim 4 wherein said slots are configured having a width corresponding with said sheet member thickness plus a tolerance equal to or less than 0.001 inch.
Claim 9
Dependent Claim
32 words
The improved gamma camera device of claim 2 wherein, for said collimator resolution, R c , said collimator means is configured having an optimal collimator geometric efficiency, φ s , where: ##EQU7##
Claim 10
Dependent Claim
69 words
The improved gamma camera device of claim 2 wherein: said array of channels comprises a plurality of sheet members of height, h, each configured having a plurality of mutually equally spaced, parallel slots of length equal to or about h/2, and a width, w; said members being mutually internested along said slots to define said array of adjacently disposed channels; and wherein, said collimator means surface-defining material is tungsten.
Claim 11
Dependent Claim
100 words
The improved gamma camera device of claim 2 wherein: said septal wall thickness, T, is equal to or about: ##EQU8## wherein, P, is the penetration fraction of said surface-defining material and has a value about equal to or less than 0.05; said array of channels comprises a plurality of sheet members of height, h, each configured having a plurality of mutually equally spaced, parallel slots of length equal to or about, h/2, and of width, w; said members being mutually internested along said slots to define said array of adjacently disposed channels; and said collimator means surface-defining material is tungsten.
Claim 12
Dependent Claim
122 words
The improved gamma camera device of claim 2 wherein: said septal wall thickness, T, is equal to or about: ##EQU9## wherein, P, is the penetration fraction of said surface-defining material and has a value about equal to or less than 0.05; said array of channels comprises a plurality of sheet members of height, h, each configured having a plurality of mutually equally spaced, parallel slots of length equal to or about, h/2, and of width, w; said member being mutually internested along said slots to define said array of adjacently disposed channels; said collimator means surface-defining material is tungsten; and wherein for said collimator resolution, R c , said collimator means is configured having an optimal collimator geometric efficiency, φs, where: ##EQU10##
Claim 13
Dependent Claim
144 words
The improved gamma camera device of claim 2 wherein: said septal wall thickness, T, is equal to or about: ##EQU11## wherein, P, is the penetration fraction of said surface-defining material and has a value about equal to or less than 0.05; said array of channels comprises a plurality of sheet members of height, h, each configured having a plurality of mutually equally spaced, parallel slots of length equal to or about, h/2, and of width, w: said members being mutually internested along said slots to define said array of adjacently disposed channels; said collimator means surface-defining material is tungsten; wherein, for said collimator resolution, R c , said collimator means is configured having an optimal collimator geometric efficiency, φ, where: ##EQU12## said slots being configured having a width corresponding with said sheet member thickness plus a tolerance equal to or less than 0.001 inch.
Claim 14
Dependent Claim
41 words
The improved gamma camera device of claim 1 wherein said septal wall thickness, T, is equal to or about: ##EQU13## wherein, P, is the penetration fraction of said surface-defining material and has a value about equal to or less than 0.05.
Claim 15
Dependent Claim
17 words
The improved gamma camera device of claim 1 wherein said collimator means surface defining material is tungsten.
Claim 16
Dependent Claim
31 words
The improved gamma camera device of claim 1 wherein said adjacently disposed channels are aligned in mutually axially parallel fashion and normal to said planes of said inward and outward sides.
Claim 17
Dependent Claim
60 words
The improved gamma camera device of claim 1 wherein: said septal wall thickness, T, is equal to or about: ##EQU14## wherein, P, is the penetration fraction of said surface-defining material and has a value of about equal to or less than 0.05; and wherein said collimator means surface-defining material is selected from a group consisting of tungsten, tantallum and lead.
Claim 18
Dependent Claim
64 words
The improved gamma camera device of claim 1 wherein: said septal wall thickness, T, is equal to or about: ##EQU15## wherein, P, is the penetration fraction of said surface-defining material and has a value about equal to or less than 0.05; and wherein, for said collimator resolution, R c , said collimator means if configured having an optimal collimator geometric efficiency, φs, where: ##EQU16##
Claim 19
Dependent Claim
177 words
In a gamma camera of a variety operative to derive image defining information of the source distribution of gamma rays exhibiting a select energy level, E, said camera incorporating an orthogonal strip array semiconductor detector for deriving spatial and energy level information corresponding with said distribution, said detector strips having a spatial frequency, v s , and center-to-center strip spacing, l, an improved collimator comprising: a plurality of sheet members of height, h, each said sheet member being configured having select number of parallel slots extending from one edge thereof along said height a distance substantially equivalent to the value h/2 and mutually spaced in a regularly recurring manner to define a slot-to-slot pitch substantially equivalent to D + T and slot width of T + e, wherein e is a predetermined tolerance dimension; any given two of said sheet members being mutually internested about a select said slot of each to form a parallel multiple channel collimator assembly each said channel of which exhibits a square channel cross-section of side dimension, D, and septal thickness, T.
Claim 20
Dependent Claim
177 words
In a gamma camera of a variety operative to derive image defining information of the source distribution of gamma rays exhibiting a select energy level, E, said camera incorporating an orthogonal strip array semiconductor detector for deriving spatial and energy level information corresponding with said distribution, said detector strips having a spatial frequency, v s , and center-to-center strip spacing, l, an improved collimator comprising: a plurality of sheet members of height, h, each said sheet member being configured having select number of parallel slots extending from one edge thereof along said height a distance substantially equivalent to the value h/2 and mutually spaced in a regularly recurring manner to define a slot-to-slot pitch substantially equivalent to D + T and slot width of T + e, wherein e is a predetermined tolerance dimension; any given two of said sheet members being mutually internested about a select said slot of each to form a parallel multiple channel collimator assembly each said channel of which exhibits a square channel cross-section of side dimension, D, and septal thickness, T.
Claim 21
Dependent Claim
16 words
The improved gamma camera of claim 18 wherein said collimator sheet members have a thickness, T.
Claim 22
Dependent Claim
29 words
The improved gamma camera of claim 18 wherein said sheet material is formed from the group consisting of tungsten and tantalum; and said slots are formed by chemically etching.
Claim 23
Dependent Claim
23 words
The improved gamma camera of claim 18 in which said slot pitch is selected in correspondence with said detector center-to-center strip spacing, l.
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) | 1980-09-05 | 1981-03-07 | 1981-09-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-09-05 | 1985-03-07 | 1985-09-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-09-05 | 1989-03-07 | 1989-09-06 | $7700.00 | Window Closed / Lapsed |