Remotely controlled apparatus and system for tracking and locating a source of photoemissions

• US 5,857,463 A
• Filed: 10/13/1995
• Issued: 01/12/1999
• Est. Priority Date: 10/13/1995
• Status: Expired due to Term

• Current Assignee: Devicor Medical Products Incorporated (Danaher Corporation)
• Original Assignee: Neoprobe Corporation
• Inventors: Olson, Karl W., Thurston, Marlin O.
• Primary Examiner(s): Lateef, Marvin M.
• Assistant Examiner(s): MANTIS MERCADER, ELENI M
• Application Number:
  US08/543,032
• Time in Patent Office: 1,187 Days
• Field of Search: 128/659, 128/654, 128/653.1, 250/370.01, 250/370.13, 250/336.1, 250/370.03
• US Class Current: 600/436
• CPC Class Codes: A61B 6/4258 for detecting non x-ray radiation, e.g. gamma radiation A61B6/037 takes precedence
• CPC Class Codes: G01T 1/161 Applications in the field of nuclear medicine, e.g. in vivo counting apparatus for radiation diagnosis A61B6/00
• CPC Class Codes: Y10S 977/873 Tip holder

Abstract

System and apparatus particularly suited for tracking a radiopharmaceutical present within a lymph duct and locating a sentinel node within which the radiopharmaceutical has concentrated. A smaller, straight, hand-held probe is employed carrying two hand actuable switches. For tracking procedures, the probe is moved in an undulatory manner wherein the location of the radiopharmaceutical containing duct is determined by observing a graphics readout developed preferably employing a circularly accessed data memory. When the region of the sentinel node is approached, a switch on the probe device is actuated by the surgeon to carry out a sequence of squelching operations until a small node locating region is defined. At that point in the procedure, the straight small probe will be pointed at and in adjacency with the radiopharmaceutical containing sentinel node. The probe-mounted switches are configured to apply preset current levels upon the probe pre-amplifier power supply. These levels are detected, identified by a discriminator and emulating signals are generated. A sterilizable remote switch provides a squelch threaded level trim function.

Claims

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, an amplifier stage within said housing adjacent said detector, responsive to said detector outputs in the presence of an applied power supply to derive count outputs at an output line, at least one piezoelectric switch mounted upon said housing, actuable to generate a switch voltage signal, a current deriving circuit arrangement, having an output coupled with said applied power supply and responsive to said switch voltage signal to impose a current signal of predetermined amplitude at said applied power supply;

a control assembly located remotely from said probe, having at least one function selection switch actuable to derive a function input, a power supply network for deriving said applied power supply, an input network for receiving and evaluating said count outputs to derive count associated signals, an output component responsive to an applied output signal to generate a perceptible output, a processor responsive to said function input and said count associated outputs to derive a said output signal corresponding therewith, a monitoring amplifier stage responsive to current levels of said applied power supply for providing a monitor output corresponding therewith, and a level comparator circuit responsive to a said monitor output corresponding with the presence of said current signal to derive an emulating signal corresponding with said function input and effecting said processor derivation of said perceptible output; and

an elongate flexible connector assembly coupled between said probe and said control assembly for coupling said output line with said input network and for conveying said applied power supply from said power supply network to said amplifier stage of said probe.

2. The system of claim 1 in which said current deriving circuit is a voltage comparator having an input responsive to said switch voltage signal.

3. The system of claim 1 in which:

said control assembly monitoring amplifier stage includes an amplifier responsive to said current levels for providing said monitor output as a monitor voltage signal of given level; and

said level comparator circuit is responsive to said monitor voltage signal when said given level thereof exceeds a predetermined threshold level to provide a comparator output, and including a pulse forming network for deriving said emulating signal.

4. The system of claim 3 in which:

said processor is responsive to said function input to derive a base count by counting said count associated signals for a predetermined base count interval and for increasing said base count by a value of statistical significance to derive a count threshold level, said processor deriving said output signal when said count associated signals exceed said threshold level; and

said output component is configured to generate an aurally perceptible output.

5. The system of claim 1 in which:

said hand manipular probe includes a first said piezoelectric switch and a second said piezoelectric switch actuable to derive respective first and second switch voltage signals and said current deriving circuit arrangement is responsive to said first and second switch voltage signals to impose first and second current signals of respective first and second predetermined amplitudes at said applied power supply;

said control assembly includes a first and a second said function selection switch actuable to derive respective first and second function inputs;

said monitoring amplifier stage provides a first said monitor output in response to a said first current signal and a second said monitor output in response to a said second current signal;

said level comparator circuit includes a first comparator having an output, L, when said first monitor output exhibits an amplitude of value above a threshold value, and when said second monitor output exhibits an amplitude of value above said threshold value;

said level comparator circuit includes a second comparator having an output, H, when said second monitor output exhibits an amplitude of value above an upper value;

a discriminator circuit responsive to said output, L, and said output, H, to generate a first discriminator output in correspondence with a said actuation of said first piezoelectric switch and a second discriminator output in correspondence with a said actuation of said second piezoelectric switch, and an emulator network responsive to said first discriminator output to derive a first said emulating signal corresponding with said first function input and responsive to said second discriminator output to derive a second said emulating signal corresponding with said second function input.

6. The system of claim 5 in which said discriminator circuit is an asynchronous, fundamental mode discriminator circuit having three stable states a, b, and c, and having no event output conditions when in a said stable state, said discriminator circuit transitioning with no event output conditions from state a to state b upon the occurrence of said output, L, without the presence of said output, H, and transitioning from said state b to said state a to provide said first discriminator output upon the termination of said output, L, during state b without the presence of said output, H.

7. The system of claim 6 in which said discriminator circuit is responsive, when in stable state b, to said output L and said output H to transition, with no event output conditions, to said stable state c, and is responsive to transition from said state c to said state a to provide said second discriminator output upon the termination of said outputs L and H.

8. The system of claim 5 in which said discriminator circuit is responsive, when in stable state b, to said output L and said output H to transition with no event output conditions to said stable state c, and is responsive, when in said stable state c, to the termination of said output, L to remain in said stable state c.

9. The system of claim 5 in which said discriminator circuit is responsive, when in stable state b, to said output L and said output H to transition with no event output conditions to said stable state c, and is responsive, when in said stable state c, to the termination of said output, H, to remain in said stable state c.

10. The system of claim 5 in which said discriminator circuit is responsive, when in said stable state a, to said output, H, in the absence of said output, L, to transition with no event output conditions, to said stable state c.

11. The system of claim 5 in which said discriminator circuit is responsive, when in said stable state a, to said outputs L and H to transition with no event output conditions to said stable state c.

12. A system for locating and differentiating a sentinel lymph node wherein a radiopharmaceutical providing photon emissions is applied at the situs of neoplastic tissue for movement with lymph along a lymph duct toward said sentinel lymph node;

comprising;

a hand manipular probe having a housing, a crystal detector assembly within said housing having an outwardly disposed surface and responsive to said photon emissions to provide corresponding count outputs;

a control assembly having an input network for receiving and evaluating the energy levels of said count outputs to derive count associated signals, having a processing network compiling said cot associated signals over predetermined time intervals to derive a sequence of count rate values; and

a display assembly responsive to said count rate values to provide a visual graphic output representing said count rate values as amplitudes with respect to time corresponding with the movement of said probe along a path generally transverse to said duct.

13. A system for locating a sentinel lymph node wherein a radiopharmaceutical providing photon emissions is applied at the situs of neoplastic tissue for movement with lymph along a lymph duct toward said sentinel lymph node, comprising:

a hand manipular probe having a housing, a crystal detector forwardly disposed within said housing having an outwardly disposed surface supported in perpendicular relationship with an orientation axis, responsive to said emissions impinging upon said surface to provide corresponding detector outputs, an amplifier stage within said housing adjacent said detector, responsive to said detector outputs in the presence of an applied power supply to derive count outputs at an output line, a piezoelectric switch mounted upon said housing, actuable to generate a switch voltage signal, a current deriving circuit arrangement having an output coupled with said applied power supply and responsive to said switch voltage signal to impose a current signal of predetermined amplitude at said applied power supply;

a control assembly located remotely from said probe having a range switch actuable to derive a count rate threshold input signal, a power supply network for deriving said applied power supply, an input network for receiving and evaluating said count outputs to derive count associated signals, a first output component responsive to an applied first output signal to generate an aurally perceptible output, a second output component responsive to count rate values to provide a visual graphic output representing said count rate values and amplitudes with respect to time, a processor responsive to said count rate input signal and said count associated outputs to selectively derive a count rate threshold based said first output signal, said processor being further responsive to said count associated outputs to derive count associated signals and compiling said count associated signals over predetermined time intervals to derive a sequence of said count rate values for application to said second output component, said control assembly including a monitoring amplifier stage responsive to current levels of said applied power supply for providing a monitor output, and a level comparator circuit responsive to said monitor output corresponding with the presence of said current applied signal to derive an emulating signal corresponding with said count rate input signal and effecting said processor response thereto; and

an elongate flexible connector assembly coupled between said probe and said control assembly for coupling said output line with said input network and for conveying said applied power supply from said power supply network to said amplifier stage of said probe.

14. The system of claim 13 in which:

said control assembly monitoring amplifier stage includes;

an amplifier responsive to said current levels for providing said monitor output as a monitor voltage signal of given level; and

said level comparator circuit is responsive to said monitor voltage signal when said given level thereof exceeds a predetermined threshold level to provide a comparator output, and including a pulse forming network for deriving said emulating signal.

15. The system of claim 14 in which:

said processor is responsive to said count rate threshold input signal to derive a base count by counting said count associated signals for a predetermined base count interval and for increasing said base count by a value of statistical significance to derive a count threshold level, said processor deriving said first output signal when subsequent said count associated signals exceed said threshold level.

16. The system of claim 13 in which said control assembly processing network is configured for initially compiling said count associated signals for first intervals of time to provide first count rate increment values and said first count rate increment values are compiled for second intervals of time greater than said first intervals of time to provide said count rate values as said visual graphic output.

17. The system of claim 16 in which said processing network updates said count rate values at successive intervals corresponding with said first intervals of time.

18. The system of claim 16 in which each said updated count rate value is published as a pixel at said second output component at successive said first intervals of time.

19. A system for locating a sentinel lymph node wherein a radiopharmaceutical providing photon emissions is applied at the situs of neoplastic tissue for movement with lymph along a lymph duct to collect in said sentinel lymph node, comprising:

a hand manipular probe having a housing, a crystal detector assembly within said housing, having an outwardly disposed surface supported in perpendicular relationship with an orientation axis, said probe being responsive to said emissions impinging upon said surface to provide corresponding count outputs;

a control assembly responsive to said count outputs to derive count rate values corresponding therewith, said control assembly being actuable to compile said count outputs over a squelch interval and derive an initial squelch threshold count rate value and subsequently deriving an aurally perceptible output when said derived count rate values exceed said squelch threshold count rate value, and responsive to a threshold trim signal for changing said initial and subsequently changed values of said squelch threshold count rate value; and

a squelch value trim assembly positionable remotely from said control assembly and coupled in signal transfer communication with said control assembly including at least one switch manually actuable to derive said threshold trim signal.

20. The system of claim 19 in which:

said quelch value trim assembly includes a first switch actuable to effect an increasing change in the value of said squelch threshold count rate value, and further includes a second switch actuable to effect a decreasing change in the value of said squelch threshold count rate value; and

said control assembly perceptible output is an aurally perceptible output.

21. A system for locating and differentiating a sentinel lymph node wherein a radiopharmaceutical providing photon emissions is applied at the situs of neoplastic tissue for movement with lymph along a lymph duct toward said sentinel lymph node;

comprising;

a hand manipular probe having a housing, a crystal detector assembly within said housing having an outwardly disposed surface and responsive to said photon emissions to provide corresponding count outputs;

a control assembly having an input network for receiving and evaluating the energy levels of said count outputs to derive count associated signals, having a processing network compiling said count associated signals over predetermined time intervals to derive a sequence of count rate values;

a display assembly responsive to said count rate values to provide a visual graphic output representing said count rate values as amplitudes with respect to time corresponding with the movement of said probe in a path generally transverse to said duct; and

said control assembly processing network being configured for initially compiling said count associated signals for first intervals of time to provide first count rate increment values and said first count rate increment values are compiled for second intervals of time greater than said first intervals of time to provide said count rate values for deriving said visual graphic output.

22. The system of claim 21 in which said processing network updates said count rate values at successive intervals corresponding with said first intervals of time.

23. The system of claim 22 in which each said updated count rate value is published as a pixel at said display assembly at successive said first intervals of time.

24. A system for locating and differentiating a sentinel lymph node wherein a radiopharmaceutical providing photon emissions is applied at the situs of neoplastic tissue for movement with lymph along a lymph duct toward said sentinel lymph node, comprising:

a hand manipular probe having a housing, a crystal detector assembly within said housing having an outwardly disposed surface and responsive to said photon emissions to provide corresponding count outputs;

a control assembly having an input network for receiving and evaluating the energy levels of said count outputs to derive count associated signals, having a processing network configured as a uniformly weighted moving average filter compiling said count associated signals over predetermined time intervals to derive a sequence of count rate values; and

a display assembly responsive to said count rate values to provide a visual graphic output representing said count rate values as amplitudes with respect to time corresponding with the movement of said probe in a path generally transverse to said duct.