US3862425A
Expired / Lapsed
US
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Radiation position detectors
Assignee: National Research Development Corp UK
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Filing: 1973-03-05
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Granted: 1975-01-21
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Expires: 1993-03-05
Abstract
Abstract A radiation position detector is described particularly for detecting the source of gamma radiation over which a gamma camera is scanned. Electrical signals are generated representing the coordinates of the focal point of the gamma camera and of the received radiation. The received radiation signals are multiplied by a compensating factor to correct for a particular depth of radiation so that radiation starting at that depth is in focus. The corrected signals and the camera co-ordinate signals are combined so that a picture can be obtained in focus for the particular depth. Multiplexing may be used to provide correction for a plurality of depths.
Inventors
- 👤 Melvyn John Myers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:59
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/29; G01T1/2914; G01T1/2985; G01T1/16; G01T1/161; G01T1/164; G01T1/1641; G01T1/1642; G21; G21K; G21K1/00; G21K1/02; G21K1/025; A; A61; A61B; A61B6/00; A61B6/42; A61B6/4208; A61B6/4258
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
129 words
A radiation position detecting device having a collimator for collimating radiation, means for deriving electrical signals representing the co-ordinates of the collimated radiation, means for deriving a signal representing the co-ordInates of the focal point of the collimator, means for compensating the received radiation signal by multiplication of the latter by a constant representing the distance between a selected plane parallel to the focal plane of the collimator and the focal plane itself, and the distance between the focal plane and the plane in which the collimated radiation is detected; and means for combining the coordinate signals of the focal point of the collimator with the received radiation signals so that the resultant signals are corrected to give the true co-ordinates of any events occurring in the selected plane.
Claim 2
Dependent Claim
129 words
A radiation position detecting device having a collimator for collimating radiation, means for deriving electrical signals representing the co-ordinates of the collimated radiation, means for deriving a signal representing the co-ordInates of the focal point of the collimator, means for compensating the received radiation signal by multiplication of the latter by a constant representing the distance between a selected plane parallel to the focal plane of the collimator and the focal plane itself, and the distance between the focal plane and the plane in which the collimated radiation is detected; and means for combining the coordinate signals of the focal point of the collimator with the received radiation signals so that the resultant signals are corrected to give the true co-ordinates of any events occurring in the selected plane.
Claim 3
Dependent Claim
47 words
A device as claimed in claim 1 wherein the means for deriving a signal representing the co-ordinates of the focal point of the collimator comprise a pair of potentiometers the values of which vary in accordance with relative movement between the collimator and an area being scanned.
Claim 4
Dependent Claim
47 words
A device as claimed in claim 1 wherein the means for compensating the received radiation signal comprises a resistance network to which the received radiation signal is supplied, the radiation network including a plurality of resistances relatively proportioned so that the received radiation signal is appropriately compensated.
Claim 5
Dependent Claim
31 words
A device as claimed in claim 1 wherein the means for deriving the electrical signals representing the co-ordinates of the collimated radiation comprises a scintillation crystal, and a matrix of photodetectors.
Claim 6
Dependent Claim
31 words
A device as claimed in claim 4, wherein the means are provided for weighing the outputs of the photodetectors by given factors in both the X- and the Y- co-ordinate directions.
Claim 7
Dependent Claim
34 words
A device as claimed in claim 5, wherein means are provided for the outputs of the photodetector along the X- and Y-co-ordinates to derive the electrical signals representing the co-ordinates of the collimated radiation.
Claim 8
Dependent Claim
66 words
A device as claimed in claim 1, and comprising means for separating the received radiation signals into a number of equal signals, and means for multiplying each of these signals with a different compensating value, the compensating values representing a range of depths, so that each of the separated received radiation signals is corrected to give the true co-ordinates of events occurring in a selected plane.
Claim 9
Dependent Claim
48 words
A device as claimed in claim 7, and including means for sampling the received radiation signals, for dividing the sampled signals into equal pulses, for multiplying each pulse with a selected compensating value, and for multiplexing the resultant signals so that they can be individually stored or displayed.
Claim 10
Dependent Claim
58 words
A device in claimed in claim 8 further including means for summing the outputs of the photodetectors in the X- and Y-co-ordinates, and a pulse height analyser giving an output pulse if the summed photodetector is of or above a predetermined magnitude to a pulse generator, the pulse generator generating a train of pulses controlling said multiplexing means.
Claim 11
Dependent Claim
19 words
A device as claimed in claim 9 and including a cathode ray tube for displaying the compensated output signal.
Claim 12
Dependent Claim
113 words
A device as claimed in claim 10 and including a colour coding device for emphasing contrast between in and out of focus pictures on the cathode ray tube, the coding device comprising a plurality of colour filters which can be moved in front of the screen of the cathode ray tube, a count rate meter which generates an electrical signal which varies as the activity seen by the camera varies during scanning, and means for controlling the movement of said colour filters in response to the latter signal so that activity particular plane causing a high count rate will show up as an in-focus picture in a colour corresponding to that count rate.
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) | 1978-01-20 | 1978-07-22 | 1979-01-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-20 | 1982-07-22 | 1983-01-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-20 | 1986-07-22 | 1987-01-21 | $7700.00 | Window Closed / Lapsed |