Systems and methods for detecting tissue contact and needle penetration depth

• US 20050283117A1
• Filed: 08/23/2005
• Published: 12/22/2005
• Est. Priority Date: 09/30/2002
• Status: Active Grant

• Current Assignee: Dagmar Beyerlein
• Original Assignee: Dagmar Beyerlein
• Inventors: Beyerlein, Dagmar
• Granted Patent: US 7,106,574 B2
• Time in Patent Office: Days
• US Class Current: 604/117
• CPC Class Codes: A61B 5/053 Measuring electrical impedance or conductance of a portion of the body
• CPC Class Codes: A61B 5/6885 Monitoring or controlling sensor contact pressure
• CPC Class Codes: A61M 25/0084 being one or more injection needles
• CPC Class Codes: A61N 1/30 Apparatus for iontophoresis, i.e. transfer of media in ionic state by an electromotoric force into the body, or cataphoresis
• CPC Class Codes: Y10T 29/43 Electric condenser making
• CPC Class Codes: Y10T 29/49169 Assembling electrical component directly to terminal or elongated conductor

Abstract

A system for detecting tissue contact and penetration depth. The system comprises a needle sheath having a needle sheath inner diameter and a needle sheath outer diameter. A first conductive region is disposed on the needle sheath inner diameter. A needle having a needle insulation layer on the outer diameter upon which a second conductive region is disposed within the first conductive region. A dielectric layer is disposed between the first conductive tube and the second conductive tube. A capacitance sensor is coupled to the first conductive region and the second conductive region.

Claims

1-28. -28. (canceled)

29. A method of detecting tissue contact and a needle penetration depth of a needle used internally to deliver a therapeutic agent to a patient comprising:

providing a delivery catheter having a capacitor that can indicate movement of a needle included within said delivery catheter;

measuring an initial capacitance;

advancing said needle toward a target site while continuously obtaining capacitance measurements as said needle is being advanced; and

determining travel distances by said needle based on said capacitance measurements.

30. The method of claim 29 further comprising:

comparing said capacitance measurements to a predetermined capacitance value, said capacitance value indicates a predetermined penetration depth by said needle when said needle reaches said target site; and

stopping said advancing of said needle when at least one of said capacitance measurements is about equal to said predetermined capacitance value.

31. The method of claim 29 wherein said capacitor further comprises:

a needle sheath having a needle sheath inner diameter and a needle sheath outer diameter;

a first conductive region disposed on said needle sheath inner diameter;

a needle insulation layer on the outer diameter of a needle;

a second conductive region disposed on said insulation layer on said needle outer diameter, said needle being disposed within said first conductive region;

a dielectric layer disposed between said first conductive region and said second conductive region; and

a capacitance sensor coupled to said first conductive region and said second conductive region.

32. The method of claim 29 wherein said capacitor further comprises:

a needle sheath having a needle sheath inner diameter and a needle sheath outer diameter;

a first conductive region disposed on said needle sheath inner diameter;

a dielectric layer disposed between said first conductive region and said needle wherein said needle being made out of a conductive material, wherein a first portion along said needle on a needle outer diameter is surrounded by an insulation layer and a second portion along said needle on said outer diameter is not surrounded by said insulation layer, said needle being disposed within said first conductive region; and

a capacitance sensor coupled to said first conductive region and said second portion along said needle.

33. A method of making a capacitor for a delivery catheter comprising:

providing a needle sheath;

disposing a first conductive region within said needle sheath;

disposing a needle having a section covered with a needle insulation layer upon which a second conductive region is disposed within said needle sheath; and

coupling a capacitance sensor to said needle sheath to measure capacitance created by said first conductive region and said second conductive region.

34. The method of claim 33 further comprising:

disposing a ring within said needle sheath at a proximal end of said needle sheath wherein said needle is disposed into said needle sheath through said ring.

35. The method of claim 33 further comprising:

disposing a dielectric region between said first conductive region and said second conductive region.

38. The method of claim 33 further comprising:

disposing a dielectric region between said first conductive region and said second portion of said needle.

36. A method of making a capacitor for a delivery catheter comprising:

providing a needle sheath;

disposing a first conductive region within said needle sheath;

disposing a needle made out of a conductive material within said needle sheath, said needle having a first portion covered with an insulation layer and a second portion not covered by said insulation layer; and

coupling a capacitance sensor to said needle sheath to measure capacitance created by said first conductive region and said second portion of said needle.

37. The method of claim 36 further comprising:

disposing a ring within said needle sheath at a proximal end of said needle sheath wherein said needle is disposed into said needle sheath through said ring.