US5173608A
Expired / Lapsed
US
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Method for correcting positional shift of gamma camera apparatus and positional shift correcting apparatus thereof
Assignee: Toshiba Corp
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Filing: 1991-02-22
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Granted: 1992-12-22
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Expires: 2011-02-22
Abstract
Abstract In a gamma camera apparatus, positional shifts contained in an output coordinate matrix of a gamma-ray detector by a method comprising the steps of: positioning a reference RI (radio isotope) source at a first reference position the gamma-ray detector so as to obtain a first positional-information coordinate output from the gamma-ray detector; processing the first positional-information coordinate output indicative of a second reference position with respect to the matrix output derived from the detector so as to produce positional correction data; acquiring a third positional-information coordinate output from the detector while injecting a radio isotope into a biological body under medical examination; and, correcting the third positional-information coordinate output based upon the positional correction data.
Inventors
- 👤 Nobutoku Motomura
- 👤 Takashi Ichihara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 23:18
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/16; G01T1/161; G01T1/164; G01T1/1641; G01T1/1648; G01T1/1642; A; A61; A61B; A61B6/00; A61B6/02; A61B6/03; A61B6/037
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
135 words
A method for correcting a positional shift containing a positional-information coordinate output in a matrix form derived from a gamma camera apparatus having at least a first gamma-ray detector, comprising the steps of: positioning a reference RI (radio isotope) source at a center position of the first gamma-ray detector; detecting a first positional-information coordinate output by said first gamma-ray detector; comparing said first positional-information coordinate output with a second positional-information coordinate signal corresponding to a center position of the matrix to produce positional correction data indicative of a difference between said first positional-information coordinate output and said second positional-information coordinate signal; acquiring by said first gamma-ray detector a third positional-information coordinate output of an RI injected into an object under medical examination; and, correcting the third positional-information coordinate output based upon said positional correction data.
Claim 2
Independent Claim
135 words
A method for correcting a positional shift containing a positional-information coordinate output in a matrix form derived from a gamma camera apparatus having at least a first gamma-ray detector, comprising the steps of: positioning a reference RI (radio isotope) source at a center position of the first gamma-ray detector; detecting a first positional-information coordinate output by said first gamma-ray detector; comparing said first positional-information coordinate output with a second positional-information coordinate signal corresponding to a center position of the matrix to produce positional correction data indicative of a difference between said first positional-information coordinate output and said second positional-information coordinate signal; acquiring by said first gamma-ray detector a third positional-information coordinate output of an RI injected into an object under medical examination; and, correcting the third positional-information coordinate output based upon said positional correction data.
Claim 3
Dependent Claim
27 words
A method as claimed in claim 1, wherein said center position of said gamma-ray detector is a geometrical center position on a surface of said gamma-ray detector.
Claim 4
Dependent Claim
47 words
A method as claimed in claim 1, wherein second and third gamma-ray detectors are positioned in such a manner that center positions of said first to third gamma-ray detectors are selected to be geometrical rotation centers when said first through third detectors are rotated around said object.
Claim 5
Dependent Claim
33 words
A method as claimed in claim 1, wherein said comparing step is performed by subtracting said second positional-information coordinate output from said first positional-information coordinate output, whereby said positional correction data are obtained.
Claim 6
Dependent Claim
25 words
A method as claimed in claim 1, wherein said correcting step is performed by subtracting said positional correction data from the third positional-information coordinate output.
Claim 7
Dependent Claim
30 words
A method as claimed in claim 1, further comprising: second and third gamma-ray detectors equidistantly separated from each other with reference to the first gamma-ray detector along a rotation direction.
Claim 8
Dependent Claim
17 words
A method as claimed in claim 1, wherein said reference RI source is a point-shaped RI source.
Claim 9
Dependent Claim
158 words
A gamma camera apparatus comprising: at least a first gamma-ray detector means for obtaining a first positional-information coordinate output in a matrix form representing a first reference position by detecting gamma rays radiated from a reference RI (radio isotope) source positioned at a predetermined position with respect to said first gamma-ray detector means; positional-data processing means for processing the first positional-information coordinate output based upon a second positional-information coordinate signal in a matrix form indicative of a second reference position with respect to a matrix output derived from the first gamma-ray detector means to produce positional correction data; said first gamma-ray detector means further detecting gamma-rays emitted from a radio isotope injected into a biological body under medical examination to obtain a third positional-information coordinate output in a matrix form; said positional-data processing means correcting the third positional-information coordinate output based upon the positional correction data whereby positional shifts contained in the third positional-information correction output are removed.
Claim 10
Dependent Claim
158 words
A gamma camera apparatus comprising: at least a first gamma-ray detector means for obtaining a first positional-information coordinate output in a matrix form representing a first reference position by detecting gamma rays radiated from a reference RI (radio isotope) source positioned at a predetermined position with respect to said first gamma-ray detector means; positional-data processing means for processing the first positional-information coordinate output based upon a second positional-information coordinate signal in a matrix form indicative of a second reference position with respect to a matrix output derived from the first gamma-ray detector means to produce positional correction data; said first gamma-ray detector means further detecting gamma-rays emitted from a radio isotope injected into a biological body under medical examination to obtain a third positional-information coordinate output in a matrix form; said positional-data processing means correcting the third positional-information coordinate output based upon the positional correction data whereby positional shifts contained in the third positional-information correction output are removed.
Claim 11
Dependent Claim
70 words
A gamma camera apparatus as claimed in claim 8, wherein said positional-data processing means includes: a CEL(correction of energy and linearity)-data correcting circuit for subtracting the second positional-information coordinate output from the first positional-information coordinate output to obtain the positional correction data; and, an offset correcting circuit for subtracting the positional correction data from the third positional-information coordinate data to eliminate the positional shifts from the third positional-information coordinate data.
Claim 12
Dependent Claim
28 words
A gamma camera apparatus as claimed in claim 9, wherein said offset correcting circuit is constructed of a register, a subtracter and a local CPU (central processing unit).
Claim 13
Dependent Claim
53 words
A gamma camera apparatus as claimed in claim 8, wherein said first reference position is selected to be a geometrical center position defined at a detecting surface of the first gamma-ray detector means, and the second reference position is selected to be a center position of the matrix output from the detector means.
Claim 14
Dependent Claim
50 words
A gamma camera apparatus as claimed in claim 8, wherein said first reference position is selected to be a rotation center defined while the first gamma-ray detector means is rotated, and the second reference position is selected to be a center position of the matrix output from the detector means.
Claim 15
Dependent Claim
34 words
A gamma camera apparatus as claimed in claim 8, further comprising: second and third gamma-ray detector means equidistantly separated from each other with reference to the first gamma-ray detector means along a rotation direction.
Claim 16
Dependent Claim
19 words
A gamma camera apparatus as claimed in claim 8, wherein said reference RI source is a point-shaped RI source.
Claim 17
Independent Claim
136 words
A method for correcting a positional shift containing a positional-information coordinate output in a matrix form derived from a gamma camera apparatus having at least a first gamma-ray detector, comprising the steps of: positioning a reference RI (radioisotope) source at a predetermined position with respect to the first gamma-ray detector; detecting a first positional-information coordinate output by said first gamma-ray detector; comparing said first positional-information coordinate output with a second positional-information coordinate signal corresponding to said predetermined position on the matrix form to produce positional correction data indicative of a difference between said first positional-information coordinate output and said second positional-information coordinate signal; acquiring by said first detector a third positional-information coordinate output of an RI injected into an object under medical examination; and, correcting the third positional-information coordinate output based on said positional correction data.
Claim 18
Independent Claim
136 words
A method for correcting a positional shift containing a positional-information coordinate output in a matrix form derived from a gamma camera apparatus having at least a first gamma-ray detector, comprising the steps of: positioning a reference RI (radioisotope) source at a predetermined position with respect to the first gamma-ray detector; detecting a first positional-information coordinate output by said first gamma-ray detector; comparing said first positional-information coordinate output with a second positional-information coordinate signal corresponding to said predetermined position on the matrix form to produce positional correction data indicative of a difference between said first positional-information coordinate output and said second positional-information coordinate signal; acquiring by said first detector a third positional-information coordinate output of an RI injected into an object under medical examination; and, correcting the third positional-information coordinate output based on said positional correction data.
Claim 19
Dependent Claim
47 words
A method as claimed in claim 15, wherein second and third gamma-ray detectors are positioned in such a manner that center positions of said first to third gamma-ray detectors are selected to be geometrical rotation centers when said first through third detectors are rotated around said object.
Claim 20
Independent Claim
146 words
A method for correcting a positional shift containing a positional-information coordinate output in a matrix form derived from a gamma camera apparatus having at least a first gamma-ray detector, comprising the step of: positioning a first reference RI (radioisotope) source having a predetermined pattern on said first detector; detecting an output of said first reference RI source by said first detector; obtaining linearity-correction data to correct a non-linearity of said first detector from distortion between output of said first reference RI source and said pattern and; positioning a second reference RI source at a predetermined position on said first gamma-ray detector; detecting a positional-information coordinate output of said second reference RI source by said first detector; calculating an offset value between an electrical signal corresponding to said predetermined position and said positional-information coordinate output; and, offsetting said linearity correction data to compensate for said offset value.
Claim 21
Independent Claim
146 words
A method for correcting a positional shift containing a positional-information coordinate output in a matrix form derived from a gamma camera apparatus having at least a first gamma-ray detector, comprising the step of: positioning a first reference RI (radioisotope) source having a predetermined pattern on said first detector; detecting an output of said first reference RI source by said first detector; obtaining linearity-correction data to correct a non-linearity of said first detector from distortion between output of said first reference RI source and said pattern and; positioning a second reference RI source at a predetermined position on said first gamma-ray detector; detecting a positional-information coordinate output of said second reference RI source by said first detector; calculating an offset value between an electrical signal corresponding to said predetermined position and said positional-information coordinate output; and, offsetting said linearity correction data to compensate for said offset value.
Claim 22
Dependent Claim
47 words
A method as claimed in claim 17, wherein second and third gamma-ray detectors are positioned in such a manner that center positions of said first to third gamma-ray detectors are selected to be geometrical rotation centers when said first through third detectors are rotated around said object.
References Cited (Backward Citations)
US4281382A
Cited
US4582995A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-12-22 | 1996-06-22 | 1996-12-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-12-22 | 2000-06-22 | 2000-12-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-12-22 | 2004-06-22 | 2004-12-22 | $7700.00 | Window Closed / Lapsed |