Patent US4287425A successfully refreshed from Google Patents.
US4287425A
Expired / Lapsed
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Construction of a CT scanner using heavy ions or protons
Assignee: Pfizer Inc
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Filing: 1979-12-31
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Granted: 1981-09-01
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Expires: 1999-12-31
Abstract
Abstract A computed tomography X-ray scanner, in which a monochromatic X-ray beam is generated by irradiating an X-ray producing target with high energy monoenergetic ions. The ion beam is preferably produced by a cyclotron. The X-ray beam is preferably rotated through an object to be scanned by angularly displacing the ion beam and target about the center axis of the object. A conventional X-ray detector array, a signal and data processor and imaging means are provided to convert detected X-ray absorption measurements into a two-dimensional visual image of the scanned object cross-section.
Inventors
- 👤 Donald O. Elliott, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 12:00
CPC Classifications
A; A61; A61B; A61B6/00; A61B6/02; A61B6/03; A61B6/032; A61B6/40; A61B6/4021; A61B6/4028; A61B6/42; A61B6/4208; A61B6/4258
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
129 words
An apparatus for obtaining a two dimensional display of the X-ray absorption distribution within a cross sectional volume of an object disposed along an axis, comprising a target; an X-ray detector spaced opposite said target; and means for producing a substantially monochromatic X-ray beam extending from said target through said axis to said detector including means for angularly displacing said beam about said axis so as to scan said object in said cross-sectional volume; said X-ray detector including means for converting said X-ray beam into a corresponding detected electrical signal; said X-ray beam producing means including a source of high energy substantially monoenergetic ions focusable on said target; and said target including atoms which are ionized by said high energy ions so as to emit substantially monochromatic X rays.
Claim 2
Independent Claim
129 words
An apparatus for obtaining a two dimensional display of the X-ray absorption distribution within a cross sectional volume of an object disposed along an axis, comprising a target; an X-ray detector spaced opposite said target; and means for producing a substantially monochromatic X-ray beam extending from said target through said axis to said detector including means for angularly displacing said beam about said axis so as to scan said object in said cross-sectional volume; said X-ray detector including means for converting said X-ray beam into a corresponding detected electrical signal; said X-ray beam producing means including a source of high energy substantially monoenergetic ions focusable on said target; and said target including atoms which are ionized by said high energy ions so as to emit substantially monochromatic X rays.
Claim 3
Dependent Claim
16 words
Apparatus in claim 1 wherein said source of substantially monoenergetic high energy ions comprises a cyclotron.
Claim 4
Dependent Claim
14 words
Apparatus as in claim 1 wherein said high energy ions comprise H 30 ions.
Claim 5
Dependent Claim
14 words
Apparatus as in claim 1 wherein said high energy ions comprise He ++ ions.
Claim 6
Dependent Claim
14 words
Apparatus as in claim 2 wherein said target comprises a thin wall of tungsten.
Claim 7
Dependent Claim
18 words
Apparatus as in claim 5 wherein said thin wall of tungsten has a thickness which exceeds 0.5 mm.
Claim 8
Dependent Claim
21 words
Apparatus as in claim 1 wherein said X-ray beam displacing means comprises means for angularly displacing said target about said axis.
Claim 9
Dependent Claim
42 words
Apparatus as in claim 7 wherein said detecting means comprises an array of contiguous X-ray energy detector elements arranged about said axis; each of said elements being responsive to incident X rays for converting said incident X rays into corresponding detected signals.
Claim 10
Dependent Claim
27 words
Apparatus as in claim 1 wherein said source of high energy substantially monoenergetic ions comprises a source of ions having kinetic energies in excess of 2 MeV.
Claim 11
Dependent Claim
27 words
Apparatus as in claim 1 wherein said source of high energy substantially monoenergetic ions comprises a source of ions having kinetic energies in excess of 25 MeV.
Claim 12
Dependent Claim
16 words
An apparatus as in claim 8 wherein said array of detector elements substantially encircles said axis.
Claim 13
Independent Claim
118 words
A method for obtaining a two dimensional display of the X-ray absorption distribution in a cross-sectional volume of an object disposed along an axis, said method comprising the steps of: (1) producing a beam of substantially monoenergetic high energy ions; (2) directing said beam of ions at a target, said target emitting substantially monochromatic X rays in response to said substantially monoenergetic ions incident thereon; (3) directing a beam of said substantially monochromatic X rays toward said axis and through said object from a plurality of points spaced equidistant from said axis; and (4) detecting said X rays after passage through said object to produce a sequence of detected electrical signals representative of X-ray absorption within said object.
Claim 14
Independent Claim
118 words
A method for obtaining a two dimensional display of the X-ray absorption distribution in a cross-sectional volume of an object disposed along an axis, said method comprising the steps of: (1) producing a beam of substantially monoenergetic high energy ions; (2) directing said beam of ions at a target, said target emitting substantially monochromatic X rays in response to said substantially monoenergetic ions incident thereon; (3) directing a beam of said substantially monochromatic X rays toward said axis and through said object from a plurality of points spaced equidistant from said axis; and (4) detecting said X rays after passage through said object to produce a sequence of detected electrical signals representative of X-ray absorption within said object.
Claim 15
Dependent Claim
28 words
Method as in claim 12 wherein said step of producing a beam of substantially monoenergetic ions comprises the step of generating said beam of ions in a cyclotron.
Claim 16
Dependent Claim
31 words
Method as in claim 12 wherein said step of directing a beam of substantially monochromatic X rays comprises the step of moving said target in a circular path about said axis.
Claim 17
Dependent Claim
75 words
An improved computed tomography X-ray scanner of the type having an X-ray producing target, an X-ray detector spaced opposite said target and arranged to receive an X-ray beam emerging from said target, said detector including means for converting said X-ray beam into a coresponding detected electrical signal, said improvement comprising a source of substantially monoenergetic high energy ions arranged to impinge upon said target and to thereby cause said X-ray beam to be substantially monochromatic.
Claim 18
Dependent Claim
75 words
An improved computed tomography X-ray scanner of the type having an X-ray producing target, an X-ray detector spaced opposite said target and arranged to receive an X-ray beam emerging from said target, said detector including means for converting said X-ray beam into a coresponding detected electrical signal, said improvement comprising a source of substantially monoenergetic high energy ions arranged to impinge upon said target and to thereby cause said X-ray beam to be substantially monochromatic.
Claim 19
Dependent Claim
22 words
An improved computed tomography X-ray scanner as in claim 15 wherein said source of substantially monoenergetic high energy ions comprises a cyclotron.
Claim 20
Dependent Claim
14 words
Apparatus as in claim 15 wherein said high energy ion comprise H + ions.
Claim 21
Dependent Claim
14 words
Apparatus as in claim 15 wherein said high energy ions comprise He ++ ions.
Claim 22
Dependent Claim
22 words
Apparatus as in claim 16 wherein said target comprises a thin wall of tungsten having a thickness in excess of 0.5 mm.
Claim 23
Dependent Claim
27 words
Apparatus as in claim 15 wherein said source of high energy substantially monoenergetic ions comprises a source of ions having kinetic energies in excess of 25 MeV.
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) | 1984-08-31 | 1985-03-02 | 1985-09-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-31 | 1989-03-02 | 1989-09-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-31 | 1993-03-02 | 1993-09-01 | $7700.00 | Window Closed / Lapsed |