US5021667A
Expired / Lapsed
US
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Movable calibration collimator and system and method using same
Assignee: Digital Scintigraphics Inc
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Filing: 1988-09-30
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Granted: 1991-06-04
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Expires: 2008-09-30
Abstract
Abstract A movable calibration collimator for a radionuclide emission tomography camera, and a calibration system using same, having a wall of material which is opaque to radionuclide emissions and is movable in a first direction relative to the camera. One or more patterns of openings are defined by the wall to pass radionuclide emissions. The openings of each pattern are aligned in a direction transverse to the first direction to provide an array of camera images upon movement of the wall relative to the camera. The number of images generated for the array are greater than the number of openings. A method of using such a calibration collimator to perform linearity correction involves installing the calibration collimator and a line source of radionuclide emissions, acquiring a camera image of the pattern of openings, and incrementing the calibration collimator for a desired number of increments. Each camera image, collected at each position of the collimator, has a position image for each opening. The camera images are combined to produce an array having a greater number of position images than the numbers of openings. Position estimation made by the camera is corrected based on the correlation between the location of the position images and the position of the openings.
Inventors
- 👤 Sebastian Genna
- 👤 Andrew P. Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 17:48
CPC Classifications
G; G21; G21K; G21K1/00; G21K1/02; G01; G01T; G01T1/00; G01T1/16; G01T1/161; G01T1/164; G01T1/1641; G01T1/1648
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
184 words
A rotatable calibration collimator for a radionuclide emission tomography camera, comprising: a wall of material which is opaque to radionuclide emissions and is rotatable in a first direction about an axis of rotation; a first pattern of openings defined by said wall for passing radionuclide emissions, said openings being aligned in a direction transverse to said first direction to provide a first array of camera images upon rotation of said wall, the first array having a greater number of images than the number of said openings; the first pattern of said openings and the first array of said images being each arranged in a plurality of rows parallel to the first direction, the first pattern having relatively few openings per row relative to the number of images per row; and the first pattern being further arranged in a plurality of columns aligned in a second direction normal to said first direction and parallel to the axis of rotation, each column having at least one opening located at a different position along said second direction relative to the location of holes in the other columns.
Claim 2
Dependent Claim
184 words
A rotatable calibration collimator for a radionuclide emission tomography camera, comprising: a wall of material which is opaque to radionuclide emissions and is rotatable in a first direction about an axis of rotation; a first pattern of openings defined by said wall for passing radionuclide emissions, said openings being aligned in a direction transverse to said first direction to provide a first array of camera images upon rotation of said wall, the first array having a greater number of images than the number of said openings; the first pattern of said openings and the first array of said images being each arranged in a plurality of rows parallel to the first direction, the first pattern having relatively few openings per row relative to the number of images per row; and the first pattern being further arranged in a plurality of columns aligned in a second direction normal to said first direction and parallel to the axis of rotation, each column having at least one opening located at a different position along said second direction relative to the location of holes in the other columns.
Claim 3
Dependent Claim
22 words
The collimator of claim 1 in which each opening in each column is located at a different position along said second direction.
Claim 4
Dependent Claim
29 words
The collimator of claim 2 in which the first array is arranged in a second plurality of columns which are greater in number than the plurality of pattern columns.
Claim 5
Dependent Claim
110 words
A calibration collimator system for a radionuclide emission tomography camera system for generating a composite image array of a set of closely spaced image positions comprising: a calibration collimator having a wall which is opaque to radionuclide emissions having a pattern formed from a subset of openings fewer in number and more widely spaced than said composite image array of said set of closely spaced image positions; and means for moving said collimator in a first direction relative to the camera in incremental steps which offset successive images of said widely spaced subset pattern of openings for generating said composite image array of said set of closely spaced image positions.
Claim 6
Dependent Claim
110 words
A calibration collimator system for a radionuclide emission tomography camera system for generating a composite image array of a set of closely spaced image positions comprising: a calibration collimator having a wall which is opaque to radionuclide emissions having a pattern formed from a subset of openings fewer in number and more widely spaced than said composite image array of said set of closely spaced image positions; and means for moving said collimator in a first direction relative to the camera in incremental steps which offset successive images of said widely spaced subset pattern of openings for generating said composite image array of said set of closely spaced image positions.
Claim 7
Dependent Claim
74 words
The calibration collimator of claim 4 in which the subset pattern of widely spaced openings and the composite image array of a set of closely spaced image positions are each arranged in a plurality of rows parallel to the first direction, the subset pattern having relatively few openings per row relative to the number of offset images per row, and said subset pattern of openings being aligned in a direction oblique to the rows.
Claim 8
Dependent Claim
20 words
The calibration collimator of claim 5 in which the subset pattern of widely spaced openings has one opening per row.
Claim 9
Dependent Claim
58 words
The calibration collimator of claim 4 in which the subset pattern of widely spaced openings is arranged in a plurality of columns aligned in a second direction normal to said first direction, each column having at least one opening located at a different position along said second direction relative to the location of openings in the other columns.
Claim 10
Dependent Claim
23 words
The calibration collimator of claim 7 in which each opening in each column is located at a different location along said second direction.
Claim 11
Dependent Claim
12 words
The calibration collimator of claim 4 in which said wall is curved.
Claim 12
Dependent Claim
13 words
The calibration collimator of claim 4 in which said wall is an annulus.
Claim 13
Dependent Claim
21 words
The calibration collimator of claim 4 in which said subset pattern of widely spaced openings are holes passing through said wall.
Claim 14
Dependent Claim
57 words
The calibration collimator system of claim 4 in which the camera has a plurality of photodetectors arranged in two or more sets, each set being parallel to the first direction, and the collimator system further includes a set of initializing openings defined by said wall, each said initializing opening being alignable with photodetectors in a different set.
Claim 15
Dependent Claim
23 words
The calibration collimator system of claim 12 in which each initializing opening is alignable with a center of photodetectors in the corresponding set.
Claim 16
Dependent Claim
21 words
The calibration collimator of claim 4 in which said subset pattern of widely spaced openings include slots passing through said wall.
Claim 17
Dependent Claim
34 words
The calibration collimator of claim 4 in which said subset pattern of widely spaced openings are slots passing through said wall, at least one of the slots being oriented transversely to the first direction.
Claim 18
Dependent Claim
29 words
The calibration collimator of claim 15 in which at least one of the slots is oriented obliquely to the first direction and the slots are non-parallel to each other.
Claim 19
Dependent Claim
161 words
A calibration system comprising: a calibration collimator; a radionuclide emission tomography camera system including: means for moving said calibration collimator relative to said camera by preselected increments in a first direction; means, responsive to said calibration collimator, for detecting radionuclide emissions from a radionuclide source to collect a camera image at each position of said calibration collimator for each increment, each camera image having a position image for each opening; and means for combining the camera images to produce a composite image array of a set of closely spaced image positions; and said calibration collimator including a wall of material which is oblique to radionuclide emission, and a subset pattern of openings defined by said wall for passing radionuclide emissions, said subset pattern of openings being aligned in a direction transverse to said first direction to provide the composite image array of camera images, the composite image array having a greater number of position images than the number of said openings.
Claim 20
Dependent Claim
161 words
A calibration system comprising: a calibration collimator; a radionuclide emission tomography camera system including: means for moving said calibration collimator relative to said camera by preselected increments in a first direction; means, responsive to said calibration collimator, for detecting radionuclide emissions from a radionuclide source to collect a camera image at each position of said calibration collimator for each increment, each camera image having a position image for each opening; and means for combining the camera images to produce a composite image array of a set of closely spaced image positions; and said calibration collimator including a wall of material which is oblique to radionuclide emission, and a subset pattern of openings defined by said wall for passing radionuclide emissions, said subset pattern of openings being aligned in a direction transverse to said first direction to provide the composite image array of camera images, the composite image array having a greater number of position images than the number of said openings.
Claim 21
Dependent Claim
61 words
The calibration collimator of claim 17 in which the subset pattern of widely spaced openings and the composite image array are each arranged in plurality of rows parallel to the first direction, said subset pattern having relatively few openings per row relative the number of offset images per row, and said openings being aligned in a direction oblique to the rows.
Claim 22
Dependent Claim
57 words
The calibration collimator of claim 17 in which the subset pattern of widely spaced openings are arranged in a plurality of columns aligned in a second direction normal to said first direction, each column having at least one opening located at different position along said second direction relative to the location of openings in the other columns.
Claim 23
Independent Claim
138 words
A method of calibrating a radionuclide emission tomography camera, comprising: installing a calibration collimator, the calibration collimator including a wall of material which is oblique to radionuclide emissions, the wall defining a subset pattern of openings few in number and widely spaced for passing radionuclide emissions, and the openings being aligned in a direction transverse to a first direction to provide a composite image array of camera images; moving the calibration collimator relative to the camera by preselected increments in the first direction; detecting radionuclide emissions from a radionuclide source to collect a camera image at each position of the calibration collimator for each increment, said camera image having a position image for each opening; and combining the camera images to produce a composite image array having a greater number of position images than the number of openings.
Claim 24
Independent Claim
138 words
A method of calibrating a radionuclide emission tomography camera, comprising: installing a calibration collimator, the calibration collimator including a wall of material which is oblique to radionuclide emissions, the wall defining a subset pattern of openings few in number and widely spaced for passing radionuclide emissions, and the openings being aligned in a direction transverse to a first direction to provide a composite image array of camera images; moving the calibration collimator relative to the camera by preselected increments in the first direction; detecting radionuclide emissions from a radionuclide source to collect a camera image at each position of the calibration collimator for each increment, said camera image having a position image for each opening; and combining the camera images to produce a composite image array having a greater number of position images than the number of openings.
Claim 25
Dependent Claim
24 words
The method of claim 20 further including locating the center of each position image, and correlating the centers with known locations of corresponding openings.
Claim 26
Dependent Claim
15 words
The method of claim 21 further including performing position estimation correction based on the correlations.
References Cited (Backward Citations)
US4095107A
Cited
US4228515A
Cited
US4507733A
Cited
US4408124A
Cited
US4593198A
Cited
US4584478A
Cited
US4873632A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-06-03 | 1994-12-03 | 1995-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-06-03 | 1998-12-03 | 1999-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-06-03 | 2002-12-03 | 2003-06-04 | $7700.00 | Window Closed / Lapsed |