US3732420A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic calibration system for a scintillation device
Assignee: Philips Nuclear Medicine Inc
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Filing: 1971-06-25
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Granted: 1973-05-08
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Expires: 1991-06-25
Abstract
Abstract A scintillation device, such as a scintillation scanner, having a calibrate system for automatically calibrating the value of data signals representative of measured radiation activity in response to the value of reference signals representative of the level of maximum radiation activity, i.e., signals representative of radiation activity at a calibration point or a ''''hot spot.'''' The calibrate system utilizes circuitry for counting the number of signals which occur at the calibration point for a predetermined number of intervals of time, and then dividing the number of counted signals by the number of intervals of time to develop calibration signals having a high degree of statistical accuracy. The values of the data signals obtained during the normal operation are then calibrated with reference to the calibrate signals to that the data signals always remain within a preselected range of values regardless of the levels of measured radiation activity.
Inventors
- 👤 C Brunnett
- 👤 B Ioannou
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 07:42
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/16; G01T1/161; G01T1/164; G01T1/166; G01T1/1641; G01T1/1648
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
189 words
In a scintillation apparatus, a radiation detector including circuitry for developing a train of electrical pulses representative of the value of radiation activity measured by the detector, the improvement comprising: counting circuit means coupled to said detector circuitry for developing a plurality of patterns of electrical signals each having a value representative of the number of electrical pulses received during a predetermined time interval; digital-to-analog converter means coupled to said counting circuit means for converting said plurality of patterns of electrical signals to a plurality of output signals each having a value representative of one of said pattern of signals; automatic calibrating circuit means coupled to said digital-toanalog converter means for modifying the values of each of said plurality of output signals in a manner so that substantially all of the values of said plurality of output signals remain within a predetermined range of values representative of the value of said pattern of signals developed by said counting circuit means; and, display means coupled to said converter means for providing output presentations representative of the values of said output signals to provide a visual representation of measured radiation activity.
Claim 2
Dependent Claim
189 words
In a scintillation apparatus, a radiation detector including circuitry for developing a train of electrical pulses representative of the value of radiation activity measured by the detector, the improvement comprising: counting circuit means coupled to said detector circuitry for developing a plurality of patterns of electrical signals each having a value representative of the number of electrical pulses received during a predetermined time interval; digital-to-analog converter means coupled to said counting circuit means for converting said plurality of patterns of electrical signals to a plurality of output signals each having a value representative of one of said pattern of signals; automatic calibrating circuit means coupled to said digital-toanalog converter means for modifying the values of each of said plurality of output signals in a manner so that substantially all of the values of said plurality of output signals remain within a predetermined range of values representative of the value of said pattern of signals developed by said counting circuit means; and, display means coupled to said converter means for providing output presentations representative of the values of said output signals to provide a visual representation of measured radiation activity.
Claim 3
Dependent Claim
106 words
An apparatus as defined in claim 1 wherein said counting circuit means includes gating means for setting the starting point of said counting circuit means and said automatic calibrating circuit means includes a binary point counter including counting means for counting the number of predetermined time intervals and memory circuit means for actuating said gating means in said counting circuit means to set a binary point in said counting circuit means in response to the number of counted time intervals to thereby cause the pattern of signals developed by said counting circuit means to be representative of the average number of couNts per interval of time.
Claim 4
Dependent Claim
32 words
An apparatus as defined in claim 2 wherein said counting circuit means is a binary counter and said gating means includes circuit means for setting the binary point of said binary counter.
Claim 5
Dependent Claim
68 words
An apparatus as defined in claim 2 including a reference storage register coupled to said counting circuit means for storing a pattern of electrical signals representative of the average number of counts per interval of time; and, normalizing circuit means coupled to said reference storage register for developing a modifying signal having a value representative of a said pattern of electrical signals stored in said reference storage register.
Claim 6
Dependent Claim
32 words
An apparatus as defined in claim 4 wherein said counting circuit means is a binary counter and said gating means includes circuit means for setting the binary point of said binary counter.
Claim 7
Dependent Claim
68 words
An apparatus as defined in claim 5 including a reference storage register coupled to said counting circuit means for storing a pattern of binary signals representative of the average number of counts per interval of time; and, normalizing circuit means coupled to said reference storage register for developing an analog signal having a value representative of a said pattern of binary signals stored in said reference storage register.
Claim 8
Dependent Claim
78 words
An apparatus as defined in claim 4 including a data storage register interposed between said counting circuit means for storing a plurality of patterns of binary signals each representative of one of the plurality of patterns of electrical signals developed by said counting circuit means; and, said digital-to-analog converter means including circuitry for converting each of said plurality of patterns of binary signals to an analog signal having a value representative of the corresponding converted pattern of signals.
Claim 9
Dependent Claim
78 words
An apparatus as defined in claim 6 including a data storage register interposed between said counting circuit means for storing a plurality of patterns of binary signals each representative of one of the plurality of patterns of electrical signals developed by said counting circuit means; and, said digital-to-analog converter means including circuitry for converting each of said plurality of patterns of binary signals to an analog signal having a value representative of the corresponding converted pattern of signals.
Claim 10
Dependent Claim
68 words
An apparatus as defined in claim 7 including control means coupled to said normalizing circuit means for applying said modifying signal to said digital-to-analog converter means for varying the value of said analog signal in response to variations in the pattern of electrical signals stored in said reference storage to thereby modify said analog signal in response to the number of counts stored in said reference storage register.
Claim 11
Dependent Claim
66 words
An apparatus as defined in claim 9 includin pulse duration circuit means coupled to said reference storage register for developing a train of electrical pulses each having a width representative of the value of a pattern of electrical signals stored in said reference storage register so that the width of said electrical pulses is representative of the number of counts stored in said reference storage register.
Claim 12
Dependent Claim
44 words
An apparatus as defined in claim 10 including a light source coupled to said pulse duration circuit means for developing a train of light flashes each having a time duration representative of the width of said electrical pulses developed by said pulse duration circuit.
Claim 13
Dependent Claim
196 words
In a scintillation apparatus, a radiation detector including circuitry for developing a train of electrical pulses representative of the value of radiation activity measured by the detector, the improvement comprising: counting circuit means coupled to said detector circuitry for developing a plurality of patterns of electrical signals each having a value representative of the number of electrical pulses received during a predetermined time interval; digital converter means coupled to said coUnting circuit means for converting said plurality of patterns of electrical signals to a plurality of output signals each having a value representative of one of said pattern of signals; contrast enhancement means including; a differential amplifier means for amplifying said output signal and having one input terminal coupled to said digital-to-analog converter means and another input terminal connected to a source of reference potential, and an output terminal; display means coupled to said output terminal of said differential amplifier for providing output presentations representative of the values of signals developed by said differential amplifier; and, variable circuit means for varying the gain of said differential amplifier in order to vary the amplification of signals applied to said recording means with reference to said reference potential.
Claim 14
Dependent Claim
196 words
In a scintillation apparatus, a radiation detector including circuitry for developing a train of electrical pulses representative of the value of radiation activity measured by the detector, the improvement comprising: counting circuit means coupled to said detector circuitry for developing a plurality of patterns of electrical signals each having a value representative of the number of electrical pulses received during a predetermined time interval; digital converter means coupled to said coUnting circuit means for converting said plurality of patterns of electrical signals to a plurality of output signals each having a value representative of one of said pattern of signals; contrast enhancement means including; a differential amplifier means for amplifying said output signal and having one input terminal coupled to said digital-to-analog converter means and another input terminal connected to a source of reference potential, and an output terminal; display means coupled to said output terminal of said differential amplifier for providing output presentations representative of the values of signals developed by said differential amplifier; and, variable circuit means for varying the gain of said differential amplifier in order to vary the amplification of signals applied to said recording means with reference to said reference potential.
Claim 15
Dependent Claim
29 words
An apparatus as defined in claim 12 including an intensity control having control means for attenuating the value of signals applied by said differential amplifier to said recording means.
Claim 16
Independent Claim
223 words
A method of calibrating a scintillation recording apparatus comprising the steps of: positioning a radiation detector in proximity to a subject under examination and in proximity to an area of substantially maximum radiation activity; developing a train of electrical pulses representative of the level of the radiation activity measured by the detector; electrically counting the number of electrical pulses for d intervals of time; electrically dividing the number of electrical pulses by d in order to obtain an average number of electrical pulses occurring in one interval of time; developing a calibration signal having a value representative of the average number of electrical pulses in one interval of time; positioning the radiation detector in proximity to another area of radiation activity; developing a second train of electrical pulses representative of the radiation activity measured by the detector at the second position; counting the number of electrical pulses in the second train of pulses which are developed in a predetermined interval of time; developing an output signal having a value representative of the number of counted pulses in the second train of pulses; and, modifying the value of the output signal with the calibration signal so that the value of the output signal substantially remains within a predetermined range of values and representative of the number of pulses in the second train of pulses.
Claim 17
Independent Claim
223 words
A method of calibrating a scintillation recording apparatus comprising the steps of: positioning a radiation detector in proximity to a subject under examination and in proximity to an area of substantially maximum radiation activity; developing a train of electrical pulses representative of the level of the radiation activity measured by the detector; electrically counting the number of electrical pulses for d intervals of time; electrically dividing the number of electrical pulses by d in order to obtain an average number of electrical pulses occurring in one interval of time; developing a calibration signal having a value representative of the average number of electrical pulses in one interval of time; positioning the radiation detector in proximity to another area of radiation activity; developing a second train of electrical pulses representative of the radiation activity measured by the detector at the second position; counting the number of electrical pulses in the second train of pulses which are developed in a predetermined interval of time; developing an output signal having a value representative of the number of counted pulses in the second train of pulses; and, modifying the value of the output signal with the calibration signal so that the value of the output signal substantially remains within a predetermined range of values and representative of the number of pulses in the second train of pulses.
Claim 18
Dependent Claim
35 words
A method as defined in claim 14 including the step of applying the output signal to an indicator means for providing an output presentation representative of the number of counted pulses in the second train.
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) | 1976-05-07 | 1976-11-06 | 1977-05-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-07 | 1980-11-06 | 1981-05-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-07 | 1984-11-06 | 1985-05-08 | $7700.00 | Window Closed / Lapsed |