EP0309165A2
Expired / Lapsed
EP
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Method for correcting sensitivity of gamma camera
Assignee: Toshiba Corp
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Filing: 1988-09-16
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Granted: —
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Expires: 2008-09-16
Abstract
Abstract A gamma camera (15) sensitivity correction device for a camera having a detector and a collimator (16), in which correction coefficients are first derived for the collimator, and then the detector's characteristic uniformity data are found with the collimator removed. From the collimator's characteristic sensitivity data and detector's characteristic uniformity data, the uniformity data in the condition with the collimator mounted on the detector are derived. Correction coefficients are then derived from these derived uniformity data. In this way, the uniformity correction matrix for sensitivity correction can be found with a small radiation source in a short time.
Inventors
- 👤 Takashi C/O Patent Division Ichihara
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 23:19
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/16; G01T1/161; G01T1/164; G01T1/1641; G01T1/1642; A; A61; A61B; A61B6/00; A61B6/42; A61B6/4208; A61B6/4258
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
143 words
A sensitivity correction device for a gamma camera in which radiation from a radioisotope administered to a subject is detected and used to obtain a radioisotope accumulation image of said subject, said correction device comprising: first calculating means for finding the sensitivity data that are characteristic of said collimator; means for freshly collecting uniformity data that are characteristic of the detector itself in the condition where said collimator is removed; means for deriving uniformity data in the condition where the collimator is mounted on said detector, based on the uniformity data from this collection means, that are characteristic of the detector itself, and on the sensitivity data from said first calculating means, that are characteristic of the collimator; and second calculating means for finding the uniformity correction coefficients for correcting the radioisotope accumulation image, based on the uniformity data from this derivation means.
Claim 2
Dependent Claim
143 words
A sensitivity correction device for a gamma camera in which radiation from a radioisotope administered to a subject is detected and used to obtain a radioisotope accumulation image of said subject, said correction device comprising: first calculating means for finding the sensitivity data that are characteristic of said collimator; means for freshly collecting uniformity data that are characteristic of the detector itself in the condition where said collimator is removed; means for deriving uniformity data in the condition where the collimator is mounted on said detector, based on the uniformity data from this collection means, that are characteristic of the detector itself, and on the sensitivity data from said first calculating means, that are characteristic of the collimator; and second calculating means for finding the uniformity correction coefficients for correcting the radioisotope accumulation image, based on the uniformity data from this derivation means.
Claim 3
Dependent Claim
66 words
A device according to claim 1, further comprising memory means for storing the collimator sensitivity characteristic data from said first calculating means, and wherein said derivation means derives uniformity data for the condition in which the collimator is mounted on said detector, based on the detector's characteristic uniformity data from said collection means and the stored data of the collimator sensitivity characteristic, from said memory means.
Claim 4
Dependent Claim
50 words
A device according to claim 1 or claim 2, the uniformity correction coefficient for the radioisotope accumulation image correction is found from: where: said correction coefficients are expressed as f(i,j), said uniformity data as F(i,j), and the total number of pixels per frame of the radioisotope accumulation image is x.y.
Claim 5
Independent Claim
37 words
A device according to any preceding claim, further comprising a correction coefficient memory means for storing said uniformity correction coefficients found by said second calculating means and wherein a correction table is formed in this memory means.
Claim 6
Dependent Claim
40 words
A device according to claim 4, further equipped with a sensitivity correction means that performs sensitivity correction using said correction table and wherein the radioisotope accumulation image data are multiplied by the correction coefficients in said correction coefficient memory means.
Claim 7
Dependent Claim
47 words
A device according to claim 4 or claim 5, further comprising self-diagnostic means which is arranged to calculate the difference between freshly collected data and previously collected data and to use this difference to make a decision as to whether or not said correction table is appropriate.
References Cited (Backward Citations)
No citation records indexed.
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