Implantable dielectrometer

• US 9,788,752 B2
• Filed: 11/20/2015
• Issued: 10/17/2017
• Est. Priority Date: 07/21/2010
• Status: Active Grant

• Current Assignee: ZOLL Medical Israel Limited (Asahi Kasei Corporation)
• Original Assignee: ZOLL Medical Israel Limited (Asahi Kasei Corporation)
• Inventors: Weinstein, Uriel, Bernstein, Assaf, Cohen, Eyal, Oppenheim, Dov, Mosesko, Moshe
• Primary Examiner(s): HINDENBURG, MAX F
• Application Number:
  US14/948,238
• Publication Number:
  US 20160073924A1
• Time in Patent Office: 697 Days
• CPC Class Codes: A61B 1/313 for introducing through surgical openings, e.g. laparoscopes
• CPC Class Codes: A61B 17/3468 for implanting or removing devices, e.g. prostheses, implants, seeds, wires devices for implanting seeds A61M37/0069
• CPC Class Codes: A61B 2560/0219 of externally powered implanted units
• CPC Class Codes: A61B 2562/0214 Capacitive electrodes
• CPC Class Codes: A61B 2562/164 the sensor is mounted in or on a conformable substrate or carrier
• CPC Class Codes: A61B 5/0028 Body tissue as transmission medium, i.e. transmission systems where the medium is the human body
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/05 Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves impedance plethysmography A61B5/0295; measuring movement of the entire body or parts thereof A61B5/11; detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof A61B5/24
• CPC Class Codes: A61B 5/0537 Measuring body composition by impedance, e.g. tissue hydration or fat content
• CPC Class Codes: A61B 5/0538 invasively, e.g. using a catheter
• CPC Class Codes: A61B 5/076 Permanent implantations telemetry using implanted circuitry A61B5/0031; implanted stimulators for therapy A61N1/3605, A61N1/362, A61N1/372
• CPC Class Codes: A61B 5/0809 by impedance pneumography
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: A61B 5/287 Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61B 5/416 the spleen
• CPC Class Codes: A61B 5/4244 liver
• CPC Class Codes: A61B 5/4552 : Evaluating soft tissue within the mouth, e.g. gums or tongue
• CPC Class Codes: A61B 5/4875 : Hydration status, fluid retention of the body
• CPC Class Codes: A61B 5/6833 : Adhesive patches
• CPC Class Codes: A61B 5/686 : Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61B 5/72 : Signal processing specially adapted for physiological signals or for diagnostic purposes character recognition, recognising digital ink, document-oriented image-based pattern recognition G06V30/00; recognition or understanding of postal images G06V30/424
• CPC Class Codes: A61N 1/36521 : the parameter being derived from measurement of an electrical impedance
• CPC Class Codes: A61N 1/3702 : Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371
• CPC Class Codes: A61N 1/37229 : Shape or location of the implanted or external antenna
• CPC Class Codes: A61N 1/3756 : Casings with electrodes thereon, e.g. leadless stimulators

Abstract

Diagnostic apparatus (24) includes a sealed case (80), comprising a biocompatible material and configured for implantation within a body of a human subject (22). A dielectrometric probe (26, 50, 63, 66, 70, 102, 160) is connected to the case and includes first and second conductors (40, 42, 54, 56, 64, 67, 68, 72, 74, 162, 164), which are configured to be placed in proximity to a target tissue (34) in the body. A driving circuit (82), which is contained in the case, is coupled to apply a radio-frequency (RF) signal to the probe and to sense the signal returned from the probe. Processing circuitry (84) is configured to evaluate, responsively to the returned signal, a dielectric property of the target tissue.

Claims

1. A diagnostic method, comprising:

implanting a dielectrometer probe, comprising first and second conductors, in proximity to a target tissue in a body of a human subject;

applying a radio-frequency (RF) signal to the probe; and

evaluating, responsively to a signal from the probe, a dielectric property of the target tissue including finding a complex permittivity of the target tissue,

wherein finding the complex permittivity of the target tissue includes one of;

measuring a reflection of the signal from the probe, which is indicative of an impedance mismatch at the target tissue;

measuring a delay of the signal transmitted through the probe; and

measuring a resonant frequency of the probe.

2. The method according to claim 1, wherein applying the RF signal comprises applying RF signals and sensing returned signals at multiple different frequencies.

3. The method according to claim 1, wherein finding the complex permittivity further includes measuring an impedance between the first and second conductors.

9. The method according to claim 1, further comprising deriving a measure of a fluid content of the target tissue from the dielectric property.

10. The method according to claim 9, wherein deriving the measure comprises measuring the fluid content continuously.

11. The method according to claim 9, wherein deriving the measure comprises measuring the fluid content intermittently.

12. The method according to claim 9, wherein deriving the measure comprises measuring changes in the fluid content over time.

13. The method according to claim 1, further comprising implanting a case, which is connected to the probe, in a thorax of the subject.

4. A diagnostic method, comprising:

implanting a dielectrometer probe, comprising first and second conductors, in proximity to a target tissue in a body of a human subject;

applying a radio-frequency (RF) signal to the probe; and

evaluating, responsively to a signal from the probe, a dielectric property of the target tissue;

wherein the first and second conductors are arranged to;

provide a coaxial contact to the target tissue at a distal end of the probe, or

define a resonant ring in proximity to the target tissue.

5. The method according to claim 4, wherein the first and second conductors are arranged to provide a coaxial contact to the target tissue at a distal end of the probe, and the coaxial contact comprises a patch, which is placed against the target tissue.

6. The method according to claim 4, wherein the first and second conductors are arranged to provide a coaxial contact to the target tissue at a distal end of the probe, and the coaxial contact comprises a coaxial tip, in which the first conductor is concentrically contained within the second conductor, wherein the tip is inserted into the target tissue.

8. The method according to claim 4, wherein the first and second conductors are arranged to define a transmission line in proximity to the target tissue and the transmission line is defined by arranging the first and second conductors as parallel lines.

14. The method according to claim 4, further comprising deriving a measure of a fluid content of the target tissue from the dielectric property.

15. The method according to claim 14, wherein deriving the measure comprises measuring changes in the fluid content over time.

16. The method according to claim 4, wherein applying the RF signal comprises applying RF signals and sensing returned signals at multiple different frequencies.

18. The method according to claim 14, wherein deriving the measure comprises measuring changes in the fluid content over time.

7. A diagnostic method, comprising:

implanting a dielectrometer probe, comprising first and second conductors, in proximity to a target tissue in a body of a human subject;

the first and second conductors arranged to define a transmission line in proximity to the target tissue;

applying a radio-frequency (RF) signal to the probe; and

evaluating, responsively to a signal from the probe, a dielectric property of the target tissue;

wherein;

the transmission line is defined by arranging the first conductor as a ground plane and the second conductor as a microstrip parallel to the ground plane;

or

the transmission line comprises a coplanar waveguide.

17. The method according to claim 7, further comprising deriving a measure of a fluid content of the target tissue from the dielectric property.

19. The method according to claim 7, wherein applying the RF signal comprises applying RF signals and sensing returned signals at multiple different frequencies.