System for locating and detecting a source of photon emissions
First Claim
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1. A system for detecting and locating a source of photon emissions emanating from tissue within a body, comprising:
- a hand manipular probe having a housing, a crystal detector forwardly disposed within said housing responsive to said emissions impinging thereon to provide corresponding detector outputs, and a signal treatment circuit within said housing responsive to said detector outputs to provide count outputs at an output;
a control assembly located remotely from said probe, having an input network for receiving and evaluating said count outputs to derive photon count signals, a converter network responsive to said photon count signals for deriving a rate output level signal corresponding with the frequency of said photon count signals, a threshold network responsive to said rate output level signal to apply a select threshold level value thereto corresponding with a value of the rate of occurrence of said count signals to derive an adjusted count rate signal, a post thresholding amplification network responsive to said adjusted count rate signal and having a gain corresponding with said threshold level value for amplifying said adjusted count rate signal to provide an amplified count rate signal at levels within a predetermined output dynamic range, and an aural cuing network having an aurally perceptive frequency output range corresponding with said predetermined output dynamic range and responsive to said amplified output signal to provide an aurally perceptive cuing output; and
transmission means connected with said probe for conveying said count outputs to said control assembly.
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Abstract
System for detecting emissions from a radiopharmaceutical injected within a lymph duct wherein a hand-held probe is utilized. When employed to locate sentinel lymph nodes, supplementary features are provided including a function for treating validated photon event pulses to determine count rate level signals. A function for count rate based ranging as well as an adjustable thresholding feature are also present. A post-threshold amplification circuit develops full-scale aural and visual outputs.
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Citations
21 Claims
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1. A system for detecting and locating a source of photon emissions emanating from tissue within a body, comprising:
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a hand manipular probe having a housing, a crystal detector forwardly disposed within said housing responsive to said emissions impinging thereon to provide corresponding detector outputs, and a signal treatment circuit within said housing responsive to said detector outputs to provide count outputs at an output; a control assembly located remotely from said probe, having an input network for receiving and evaluating said count outputs to derive photon count signals, a converter network responsive to said photon count signals for deriving a rate output level signal corresponding with the frequency of said photon count signals, a threshold network responsive to said rate output level signal to apply a select threshold level value thereto corresponding with a value of the rate of occurrence of said count signals to derive an adjusted count rate signal, a post thresholding amplification network responsive to said adjusted count rate signal and having a gain corresponding with said threshold level value for amplifying said adjusted count rate signal to provide an amplified count rate signal at levels within a predetermined output dynamic range, and an aural cuing network having an aurally perceptive frequency output range corresponding with said predetermined output dynamic range and responsive to said amplified output signal to provide an aurally perceptive cuing output; and transmission means connected with said probe for conveying said count outputs to said control assembly. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A system for detecting and locating a source of photon emissions emanating from tissue within a body, comprising:
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a hand manipular probe having a housing, a crystal detector forwardly disposed within said housing and responsive to said emissions impinging thereon to provide detector outputs, and a signal treatment circuit responsive to said detector outputs to provide count outputs at an output; a control assembly having an input network for receiving and evaluating said count outputs to derive photon count signals as pulses exhibiting a substantially constant pulse width, a frequency to voltage converter responsive to said photon count signals for deriving a rate output voltage signal having voltage values within a converter dynamic range of voltages, a ranging network including a ranging amplifier having at least two range designated gain orientations selectable in correspondence with at least two predetermined ranges of rates of occurrence of said photon count signals and responsive to said rate output voltage signal occurring at a selected said gain orientation to provide said rate output voltage signal at substantially full scale range with respect to said converter dynamic range of voltages as a ranged rate output voltage signal of given polarity, a threshold circuit having a summing stage, and a threshold signal network including a threshold variable resistor component actuable to derive a select threshold voltage of polarity opposite said given polarity and corresponding with a threshold percentage of said ranged rate output signal full scale range, said summing stage summing said select threshold voltage and said ranged rate output signal to derive an adjusted count rate signal, an aural cuing network having a frequency output range and responsive to an amplified output signal to generate an aurally perceptive output at a pitch within said frequency output range corresponding therewith, and a post threshold amplification network responsive to said adjusted count rate signal, including an amplification stage and a post threshold variable resistor component coupled in gain defining relationship with said amplification stage and actuable in correspondence with the said actuation of said threshold variable resistor component to derive said amplified output signal at full scale with respect to said frequency output range. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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Specification