US3697753A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Scintillation camera having a variable gain plural amplifier system
Assignee: Philips Nuclear Medicine Inc
•
Filing: 1969-06-18
•
Granted: 1972-10-10
•
Expires: 1989-06-18
Abstract
Abstract A scintillation camera system is disclosed having a scintillator camera which produces electrical signals corresponding to scintillation intensity and location on a scintillator. The system has circuitry for processing these signals including a plurality of signal amplifiers which individually amplify the intensity and location signals. The gain of these signal amplifiers is adjustable by a remote switch which alters the condition of gain control circuitry associated with the signal amplifiers. The disclosed signal amplifiers further include a control circuit which stabilizes the direct current (D.C.) output of the amplifiers at a particular level with respect to a reference voltage and yet permits output pulses to be produced without altering the output pulse amplitudes.
Inventors
- 👤 Ronald J Martone
- 👤 Peter G Mueller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:16
CPC Classifications
G; G01; G01T; G01T1/00; G01T1/16; G01T1/161; G01T1/164; G01T1/1641; G01T1/1642
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
227 words
In a scintillation camera system having a scintillator camera for producing electrical signals corresponding to the intensity and coordinate locations of a scintillation in a scintillator, circuitry for processing said signals comprising: a. a plurality of signal amplifiers for individually amplifying said signals; b. gain adjusting means for selectively changing the gain of all of said amplifiers simultaneously; c. said gain adjusting means including at least a first feedback loop for each amplifier, said feedback loop including an electronic switch having a state of conduction in which said feedback loop changes the gain of said amplifier; d. control electrode means for each electronic switch in each amplifier, said control electrode means being connected in parallel with each other; e. a remote switch having contacts connected to a series circuit with said electrodes and operated to establish a circuit for simultaneously conditioning said electronic switches to said state of conduction whereby the gains to said amplifiers are simultaneously changed by substantially equal amounts; f. each amplifier including output stabilizing means effective to prevent the D.C. output level of the amplifier from changing in one sense direction from a predetermined level relative to a reference signal; and, g. said output stabilizing means preventing said D.C. output voltage of each of said amplifiers from shifting in said one sense from said level when the gains of said amplifiers are changed.
Claim 2
Dependent Claim
227 words
In a scintillation camera system having a scintillator camera for producing electrical signals corresponding to the intensity and coordinate locations of a scintillation in a scintillator, circuitry for processing said signals comprising: a. a plurality of signal amplifiers for individually amplifying said signals; b. gain adjusting means for selectively changing the gain of all of said amplifiers simultaneously; c. said gain adjusting means including at least a first feedback loop for each amplifier, said feedback loop including an electronic switch having a state of conduction in which said feedback loop changes the gain of said amplifier; d. control electrode means for each electronic switch in each amplifier, said control electrode means being connected in parallel with each other; e. a remote switch having contacts connected to a series circuit with said electrodes and operated to establish a circuit for simultaneously conditioning said electronic switches to said state of conduction whereby the gains to said amplifiers are simultaneously changed by substantially equal amounts; f. each amplifier including output stabilizing means effective to prevent the D.C. output level of the amplifier from changing in one sense direction from a predetermined level relative to a reference signal; and, g. said output stabilizing means preventing said D.C. output voltage of each of said amplifiers from shifting in said one sense from said level when the gains of said amplifiers are changed.
Claim 3
Dependent Claim
91 words
A system as claimed in claim 1 wherein each amplifier includes a plurality of said feedback loops, each loop having a different impedance from the other loops and corresponding loops in different amplifiers having the same impedance when in said state of condition, said remote switch including a plurality of switch contacts at least as many in number as the number of said feedback loops in each amplifier, and the electronic switch in each loop being rendered effective only by operation of switch contacts connected to the control electrode means thereof.
Claim 4
Dependent Claim
37 words
A system as claimed in claim 1 wherein said first feedback loops associated with said amplifiers have uniform impedances whereby the gains of said amplifiers are uniformly changed by substantially equal amounts when said contacts are operated.
Claim 5
Dependent Claim
76 words
A system as claimed in claim 1 wherein said gain adjusting means further includes at least second feedback loops for each amplifier, the second feedback loop in each amplifier including an electronic switch having a control electrode, said control electrodes of said second feedback loops being electrically connected in parallel with each other, and each of said control electrodes being electrically connected in a series circuit with a second set of contacts of said remote switch.
Claim 6
Dependent Claim
88 words
A system as claimed in claim 4 wherein said first feedback loops have substantially equal impedances and said second feedback loops have a common impedance different from the impedance of said first feedback loops, said first feedback loops effective to change the gain of said amplifiers from a first gain to a second gain when said first set of switch contacts operates and said second feedback loops are effective to change the gain of said amplifier to a third gain when said second set of switch contacts operates.
Claim 7
Dependent Claim
167 words
In a scintillation camera system having a camera unit for producing separate photo-responsive signals relating to position and intensities of scintillations detected by said camera, and circuitry for processing said signals on a discriminating basis, said signal processing circuitry including: a. a plurality of amplifiers for individually amplifying said separate photo-responsive signals; b. each amplifier including output stabilizIng means effective to prevent the D.C. output level of the amplifier from changing in one sense direction from a predetermined level relative to a reference signal; c. gain control means associated with each amplifier for changing the gain of said amplifier and tending to shift said D.C. output level in said one sense direction relative to said reference signal; d. switch means for operating said gain control means to change the gains of said amplifiers simultaneously; and, e. said output stabilizing means preventing said D.C. output voltage of each of said amplifiers from shifting in said one sense from said level when the gains of said amplifiers are changed.
Claim 8
Dependent Claim
167 words
In a scintillation camera system having a camera unit for producing separate photo-responsive signals relating to position and intensities of scintillations detected by said camera, and circuitry for processing said signals on a discriminating basis, said signal processing circuitry including: a. a plurality of amplifiers for individually amplifying said separate photo-responsive signals; b. each amplifier including output stabilizIng means effective to prevent the D.C. output level of the amplifier from changing in one sense direction from a predetermined level relative to a reference signal; c. gain control means associated with each amplifier for changing the gain of said amplifier and tending to shift said D.C. output level in said one sense direction relative to said reference signal; d. switch means for operating said gain control means to change the gains of said amplifiers simultaneously; and, e. said output stabilizing means preventing said D.C. output voltage of each of said amplifiers from shifting in said one sense from said level when the gains of said amplifiers are changed.
Claim 9
Dependent Claim
60 words
A system as claimed in claim 6 wherein said stabilizing means includes a difference circuit including a branch having a first conductive condition when said D.C. output level shifts from said predetermined level in said one sense and effective in said first conductive condition to alter feedback to the amplifier for returning said D.C. output level to said predetermined level.
Claim 10
Dependent Claim
53 words
A system as claimed in claim 7 wherein said branch is in a second conductive condition when said D.C. output voltage is at said level, and said branch is ineffective to alter feedback to said amplifier when said voltage shifts in an opposite sense from said predetermined level relative to said reference level.
Claim 11
Dependent Claim
115 words
In a scintillation camera system having a scintillation camera for producing electrical output signals in response to intensity and coordinate locations of a scintillation in a scintillator, signal processing circuitry comprising: a. a signal amplifier for amplifying a signal from said camera; b. output stabilizing circuitry for preventing the D.C. output level of said amplifier from shifting in one sense direction from a predetermined level with respect to a reference level; and, c. said stabilizing circuit including a difference circuit for comparing the D.C. output level of said amplifier with said reference and for altering feedback to said amplifier in response to shifting of said output level in said sense direction from said predetermined level.
Claim 12
Dependent Claim
115 words
In a scintillation camera system having a scintillation camera for producing electrical output signals in response to intensity and coordinate locations of a scintillation in a scintillator, signal processing circuitry comprising: a. a signal amplifier for amplifying a signal from said camera; b. output stabilizing circuitry for preventing the D.C. output level of said amplifier from shifting in one sense direction from a predetermined level with respect to a reference level; and, c. said stabilizing circuit including a difference circuit for comparing the D.C. output level of said amplifier with said reference and for altering feedback to said amplifier in response to shifting of said output level in said sense direction from said predetermined level.
Claim 13
Dependent Claim
32 words
A system as claimed in claim 9 wherein said difference circuit is ineffective to alter feedback to said amplifier when said output changes in the opposite sense direction from said predetermined level.
Claim 14
Dependent Claim
61 words
A system as claimed in claim 9 wherein said signal processing circuitry includes a plurality of signal amplifiers for individually amplifying signals from said camera, each of said amplifiers including said output stabilizing circuitry effective to maintain said D.C. output levels at said predetermined level with respect to said reference level, said reference level being common to all of said amplifiers.
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) | 1975-10-10 | 1976-04-10 | 1976-10-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-10 | 1980-04-10 | 1980-10-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-10 | 1984-04-10 | 1984-10-10 | $7700.00 | Window Closed / Lapsed |