US4468744A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Scintillation camera
Assignee: Toshiba Corp
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Filing: 1981-05-18
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Granted: 1984-08-28
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Expires: 2001-05-18
Abstract
Abstract In a scintillation camera having apparatus for shortening waveforms, a regulating circuit for preventing display of signals representing unwanted γ rays having excessive intensity including a device for comparing the peak of the shortened waveform representing the total light energy received by the camera from the γ ray with a preset reference range between an upper limit and the saturation level of the pre-amplifiers of the camera and for generating a signal while the total light energy exceeds the reference range, a circuit for generating an output for a predetermined time after the signal ceases and an AND gate for blocking access to the display during the period of the output.
Inventors
- 👤 Makoto Kakegawa
- 👤 Mineki Nishikawa
- 👤 Tomohiko Kihara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 08:01
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/16; G01T1/161; G01T1/164; G01T1/1641; G01T1/1642
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
240 words
In a scintillation camera apparatus of a type having a plurality of photoelectric conversion elements arranged at the back side of a scintillator for converting a radioactive ray received by the scintillator into light, pre-amplifiers for amplifying the output signals of the respective elements, circuits for weighing the outputs of the pre-amplifiers to identify the coordinate positions of the elements corresponding to the pre-amplifiers and to generate position signals having the X- and Y-axis components of the light emitting point, a circuit for summing the outputs of the pre-amplifiers, waveform shortening circuits for intensifying and thereby shortening the time widths of the waveforms of the position signals and the summed output, a peak height analyzer for generating a signal if the peak of the shortened summed output is lower than a predetermined window level, and means for generating coordinate signals for a display device, the coordinate signals being a function of the ratio of the shortened individual position signals and the shortened summed signal if below the predetermined window level, the improvement comprising regulating circuit means for establishing a preset reference value set at a predetermned level within a range between the upper limit of said window level and the saturation level of said pre-amplifiers, means for comparing said summed output with said preset reference value and means for preventing any display on said display device for a predetermined time period after said summed output has exceeded said reference value.
Claim 2
Dependent Claim
240 words
In a scintillation camera apparatus of a type having a plurality of photoelectric conversion elements arranged at the back side of a scintillator for converting a radioactive ray received by the scintillator into light, pre-amplifiers for amplifying the output signals of the respective elements, circuits for weighing the outputs of the pre-amplifiers to identify the coordinate positions of the elements corresponding to the pre-amplifiers and to generate position signals having the X- and Y-axis components of the light emitting point, a circuit for summing the outputs of the pre-amplifiers, waveform shortening circuits for intensifying and thereby shortening the time widths of the waveforms of the position signals and the summed output, a peak height analyzer for generating a signal if the peak of the shortened summed output is lower than a predetermined window level, and means for generating coordinate signals for a display device, the coordinate signals being a function of the ratio of the shortened individual position signals and the shortened summed signal if below the predetermined window level, the improvement comprising regulating circuit means for establishing a preset reference value set at a predetermned level within a range between the upper limit of said window level and the saturation level of said pre-amplifiers, means for comparing said summed output with said preset reference value and means for preventing any display on said display device for a predetermined time period after said summed output has exceeded said reference value.
Claim 3
Dependent Claim
90 words
The improvement in a scintillation camera apparatus of claim 1, wherein said regulating circuit means includes: a presetter for presetting said reference; a comparator both for comparing said shortened summed output with the reference preset by said presetter and for generating a signal when said summed output exceeds said reference; a circuit for generating an output for a predetermined time period after the output of said comparator ceases; and means for blocking the output of said peak height analyzer during the period while the last-mentioned circuit is generating its output.
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) | 1987-08-28 | 1988-02-27 | 1988-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-28 | 1992-02-27 | 1992-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-28 | 1996-02-27 | 1996-08-28 | $7700.00 | Window Closed / Lapsed |