US3876882A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Methods and apparatus for determining the spatial distribution of a radioactive material
Assignee: National Research Development Corp UK
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Filing: 1973-03-26
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Granted: 1975-04-08
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Expires: 1993-03-26
Abstract
Abstract The spatial distribution of a radioactive material is determined by locating the positions of and energy losses resulting from Compton interactions which occur in a detector as a result of gamma photons emitted by the radioactive material, which may, for example, have been administered to a patient for medical diagnostic investigation.
Inventors
- 👤 Robert William Todd
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 12:30
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; A61B6/50; A61B6/507; H; H10; H10F; H10F99/00
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
70 words
A method of determining the spatial distribution of a radioactive material, comprising positioning a detector adjacent to the location of the radioactive material, determining the positions of and energy losses associated with Compton interactions which occur in said detector as a result of gamma photons emitted by the radioactive material, and deriving in dependence on said positions and energy losses information as to the spatial distribution of the radioactive material.
Claim 2
Independent Claim
70 words
A method of determining the spatial distribution of a radioactive material, comprising positioning a detector adjacent to the location of the radioactive material, determining the positions of and energy losses associated with Compton interactions which occur in said detector as a result of gamma photons emitted by the radioactive material, and deriving in dependence on said positions and energy losses information as to the spatial distribution of the radioactive material.
Claim 3
Dependent Claim
40 words
A method according to claim 1 wherein said detector is a semiconductor detector including means to indicate in a three-coordinate system the position of a Compton interaction in said detector and means to indicate the energy loss at the interaction.
Claim 4
Independent Claim
138 words
A method of determining the spatial distribution of a radioactive material, comprising: positioning a detector adjacent to the location of the radioactive material, said detector being a semiconductor detector with means to indicate in a three-coordinate system the position of a Compton interaction in said detector and means to indicate the energy loss at the interaction; determining the positions of two Compton interactions in said detector resulting from the same gamma photon emitted by the radioactive material and the energy loss at the first of said interactions; and deriving a probability function of the position of the source of said gamma photon in the form of an ellipse as the intersection of a cone, with a semi-angle equal to the Compton scattering angle and an axis coincident with the line joining said two positions, with the object plane.
Claim 5
Independent Claim
138 words
A method of determining the spatial distribution of a radioactive material, comprising: positioning a detector adjacent to the location of the radioactive material, said detector being a semiconductor detector with means to indicate in a three-coordinate system the position of a Compton interaction in said detector and means to indicate the energy loss at the interaction; determining the positions of two Compton interactions in said detector resulting from the same gamma photon emitted by the radioactive material and the energy loss at the first of said interactions; and deriving a probability function of the position of the source of said gamma photon in the form of an ellipse as the intersection of a cone, with a semi-angle equal to the Compton scattering angle and an axis coincident with the line joining said two positions, with the object plane.
Claim 6
Dependent Claim
80 words
Apparatus for determining the spatial distribution of a radioactive material, comprising a detector which in use of the apparatus is positioned adjacent to the location of the radioactive material, means for determining the positions of and energy losses associated with Compton interactions which occur in said detector as a result of gamma photons emitted by the radioactive material, and means for deriving in dependence on said positions and energy losses information as to the spatial distribution of the radioactive material.
Claim 7
Dependent Claim
80 words
Apparatus for determining the spatial distribution of a radioactive material, comprising a detector which in use of the apparatus is positioned adjacent to the location of the radioactive material, means for determining the positions of and energy losses associated with Compton interactions which occur in said detector as a result of gamma photons emitted by the radioactive material, and means for deriving in dependence on said positions and energy losses information as to the spatial distribution of the radioactive material.
Claim 8
Dependent Claim
39 words
Apparatus according to claim 4 wherein said detector is a semiconductor detector including means to indicate in a three-coordinate system the position of a Compton interaction in said detector and means to indicate the energy loss at the interaction.
Claim 9
Dependent Claim
98 words
Apparatus for determining the spatial distribution of a radioactive material, comprising: a detector which in use of the apparatus is positioned adjacent to the location of the radioactive material, said detector comprising a plurality of slices of semiconductor material having a Schottky barrier on the surfaces thereof; means to indicate in a three-coordinate system the position of a Compton interaction in said detector; means to indicate the energy loss at a Compton interaction in said detector; and means for deriving in dependence on said positions and energy losses information as to the spatial distribution of the radioactive material.
Claim 10
Dependent Claim
98 words
Apparatus for determining the spatial distribution of a radioactive material, comprising: a detector which in use of the apparatus is positioned adjacent to the location of the radioactive material, said detector comprising a plurality of slices of semiconductor material having a Schottky barrier on the surfaces thereof; means to indicate in a three-coordinate system the position of a Compton interaction in said detector; means to indicate the energy loss at a Compton interaction in said detector; and means for deriving in dependence on said positions and energy losses information as to the spatial distribution of the radioactive material.
Claim 11
Dependent Claim
23 words
Apparatus according to claim 6 wherein each said slice has arrays of parallel conducting strips on each major surface, the arrays being orthogonal.
Claim 12
Dependent Claim
28 words
Apparatus according to claim 7 further comprising a core matrix assembly for determining from pulses developed in said strips, the position of a Compton interaction in said slice.
Claim 13
Dependent Claim
30 words
Apparatus according to claim 7 further comprising means for determining from the amplitude of pulses developed in said strips, the energy loss associated with a Compton interaction in said slice.
Claim 14
Dependent Claim
68 words
Apparatus according to claim 6 further comprising means to determine the positions of two Compton interactions in said detector resulting from the same gamma photon, and means to determine a probability function in the from of an ellipse as the intersection of a cone, with a semi-angle equal to the Compton scattering angle and an axis coincident with the line joining said two positions, with the object plane.
Claim 15
Dependent Claim
45 words
Apparatus according to claim 10 further comprising a charge storage tube for accumulating a plurality of said probability functions, and means to produce an image indicating the spatial distribution of the radioactive material in the object plane by selecting intersection points of said probability functions.
Claim 16
Independent Claim
99 words
A method of determining the spatial distribution of a radioactive material, the method comprising: positioning adjacent to the location of the radioactive material a detector having a three-dimensional array of distinguishable positions at which there can occur Compton interactions involving gamma photons; deriving from the detector signals indicating at which of said positions Compton interactions occur as a result of gamma photons being emitted by the radioactive material and signals indicating the respective energy losses associated with such interactions; and utilizing the signals derived from the detector to derive information as to the spatial distribution of the radioactive material.
Claim 17
Independent Claim
99 words
A method of determining the spatial distribution of a radioactive material, the method comprising: positioning adjacent to the location of the radioactive material a detector having a three-dimensional array of distinguishable positions at which there can occur Compton interactions involving gamma photons; deriving from the detector signals indicating at which of said positions Compton interactions occur as a result of gamma photons being emitted by the radioactive material and signals indicating the respective energy losses associated with such interactions; and utilizing the signals derived from the detector to derive information as to the spatial distribution of the radioactive material.
Claim 18
Dependent Claim
98 words
Apparatus for determining the spatial distribution of a radioactive material, the apparatus comprising: a detector having a three-dimensional array of distinguishable positions at which there can occur Compton interactions involving gamma photons; means for deriving from the detector signals indicating at which of said positions Compton interactions occur as a result of gamma photons being emitted by a radioactive material located adjacent to said detector and signals indicating the respective energy losses associated with such interactions; and means for utilizing the signals derived from the detector to derive information as to the spatial distribution of the radioactive material.
Claim 19
Dependent Claim
98 words
Apparatus for determining the spatial distribution of a radioactive material, the apparatus comprising: a detector having a three-dimensional array of distinguishable positions at which there can occur Compton interactions involving gamma photons; means for deriving from the detector signals indicating at which of said positions Compton interactions occur as a result of gamma photons being emitted by a radioactive material located adjacent to said detector and signals indicating the respective energy losses associated with such interactions; and means for utilizing the signals derived from the detector to derive information as to the spatial distribution of the radioactive material.
Claim 20
Dependent Claim
120 words
Apparatus according to claim 13 wherein said means for utilizing the signals derived from the detector comprises: means for utilizing said signals to identify the impact on the detector of a gamma photon having an energy corresponding to that of photons emitted by a given radioactive material; means for utilizing said signals to compute, in respect of a photon whose impact is identified by the identifying means, the locus of the possible points on a given notional surface from which the photon could have been emitted by the radioactive material; and means for determining the distribution of the radioactive material over said surface by collating the loci computed by the computing means in respect of a large number of photons.
References Cited (Backward Citations)
US3140395A
Cited
US3558887A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-07 | 1978-10-07 | 1979-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-07 | 1982-10-07 | 1983-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-07 | 1986-10-07 | 1987-04-08 | $7700.00 | Window Closed / Lapsed |