Patent US3748487A successfully refreshed from Google Patents.
US3748487A
Expired / Lapsed
US
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Radiation absorbing device for radiographic apparatuses
Assignee: Medinova AB
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Filing: 1971-02-05
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Granted: 1973-07-24
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Expires: 1991-02-05
Abstract
Abstract The invention concerns a radiation absorbing device adapted to be used as a compensating filter device in radiographic apparatuses for reducing the variations in average exposure in different portions of the radiograph, whereby a substantially uniform image contrast all over the radiograph is produced. The radiation absorbing device consists of two or several bodies of a radiation absorbing material, which are coupled to each other through flexible joints so that the shape of the radiation abosrbing device can be varied and adapted to the size, shape and contour of the object being radiographed. The flexible joints between the absorption bodies are of a special design so as to produce no sharp discontinuities in the radiation absorption of the device, which might create false shadow images on the radiograph.
Inventors
- 👤 P Edholm
- 👤 N Jacobson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 19:20
CPC Classifications
A; A61; A61B; A61B6/00; A61B6/02; A61B6/03; A61B6/032; A61B6/08; A61B6/40; A61B6/4035; G; G03; G03B; G03B42/00; G03B42/02; G21; G21K; G21K1/00; G21K1/02; G21K1/04; G21K1/10
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
158 words
A filter device for the penetrative radiatiOn in a radiographic apparatus, comprising at least first and second, solid, penetrative radiation absorbing filter bodies, each of said first and second filter bodies having a varying thickness in a direction parallel to the direction of the penetrative radiation to be filtered, and a flexible joint interconnecting said first and second filter bodies so as to permit rotation of either one of said filter bodies independently of the other filter body in a plane substantially perpendicular to the direction of the penetrative radiation to be filtered, said joint including an interconnecting member and said first and second filter bodies being pivoted in said interconnecting member about individual separate pivot axes, said pivot axes being mutually parallel and spaced and substantially parallel to the direction of the penetrative radiation to be filtered and said first and second filter bodies having portions overlapping each other within the region between said spaced pivot axes.
Claim 2
Dependent Claim
158 words
A filter device for the penetrative radiatiOn in a radiographic apparatus, comprising at least first and second, solid, penetrative radiation absorbing filter bodies, each of said first and second filter bodies having a varying thickness in a direction parallel to the direction of the penetrative radiation to be filtered, and a flexible joint interconnecting said first and second filter bodies so as to permit rotation of either one of said filter bodies independently of the other filter body in a plane substantially perpendicular to the direction of the penetrative radiation to be filtered, said joint including an interconnecting member and said first and second filter bodies being pivoted in said interconnecting member about individual separate pivot axes, said pivot axes being mutually parallel and spaced and substantially parallel to the direction of the penetrative radiation to be filtered and said first and second filter bodies having portions overlapping each other within the region between said spaced pivot axes.
Claim 3
Dependent Claim
38 words
A filter device as claimed in claim 1, further comprising a third, solid, penetrative radiation absorbing filter body rigidly attached to said interconnecting member and disposed to overlap said overlapping portions of said first and second filter bodies.
Claim 4
Dependent Claim
100 words
A filter device as claimed in claim 1, wherein each of said first and second filter bodies is generally elongate and has substantially the same cross-section in all planes perpendicular to the longitudinal axis of the filter body and one end bent with a constant radius of curvature about an axis of curvature perpendicular to the longitudinal axis of the filter body, said first and second filter bodies being pivoted in said interconnecting member with their said axes of curvature coinciding with their said pivot axes in the interconnecting member and with their said bent end portions overlapping each other.
Claim 5
Dependent Claim
124 words
A filter device as claimed in claim 3, wherein said cross-section is substantially identical for both of said first and second filter bodies, and comprising a third, solid, penetrative radiation absorbing filter body rigidly attached to said interconnecting member and disposed to overlap said bent end portions of said first and second filter bodies, said third filter body having such a shape that the total combined absorbing properties of said third filter body and said overlapping bent end portions of said first and second filter bodies for a penetrative radiation which is substantially parallel to the direction of said pivot axes is substantially corresponding to the absorption properties of the non-overlapping portions of said first and second filter bodies for such a penetrative radiation.
Claim 6
Dependent Claim
82 words
A filter device as claimed in claim 3, wherein said cross-section of each of said first and second filter bodies respectively is wedge-shaped so that each of said first and second filter bodies has a thickness continuously increasing from one longitudinal edge of the filter body to the opposite longitudinal edge of the filter body, said axes of curvature of said bent end portions of said first and second filter bodies being located adjacent the thicker longitudinal edges of said filter bodies.
Claim 7
Dependent Claim
60 words
A filter device as claimed in claim 5, wherein each of said first and second filter bodies has a longitudinal side surface substantially perpendicular to said axis of curvature of said bent end portion of the filter body, and said first and second filter bodies are pivoted in said interconnecting member with their said side surfaces facing in opposite directions.
Claim 8
Dependent Claim
28 words
A filter device as claimed in claim 6, wherein said third filter body is disposed between said overlapping bent end portions of said first and second filter bodies.
Claim 9
Dependent Claim
39 words
A filter device as claimed in claim 1, wherein said filter bodies consist of a penetrative radiation absorbing material containing at least one element having a K-absorption edge within the energy spectrum of the penetrative radiation to be filtered.
Claim 10
Dependent Claim
35 words
A filter device as claimed in claim 8, wherein the K-abSorption edge of said radiation absorbing element is located close to the energy value for the intensity maximum of the penetrative radiation to be filtered.
Claim 11
Dependent Claim
49 words
A filter device as claimed in claim 8, wherein the K-absorption edge of said radiation absorbing element corresponds to an energy which multiplied with a factor within the range between 1.2 and 2.0 corresponds to the voltage used for an X-ray tube producing the penetrative radiation to be filtered.
Claim 12
Dependent Claim
18 words
A filter device as claimed in claim 8, wherein said radiation absorbing element is a rare earth metal.
References Cited (Backward Citations)
US2405444A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-23 | 1977-01-22 | 1977-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-23 | 1981-01-22 | 1981-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-23 | 1985-01-22 | 1985-07-24 | $7700.00 | Window Closed / Lapsed |