Microwave ablation instrument with insertion probe

A microwave ablation assembly for insertion through an insert passage of an elongated metallic biopsy needle having a penetration end adapted to penetrate into bio-tissue, said insert passage extending from an access opening to an insert opening at the penetration end, said ablation assembly comprising:

• a coaxial transmission line including an inner conductor and an outer conductor separated by a dielectric material medium, and having a proximal end thereof coupled to a microwave energy source;
• and
• an antenna device for generating an electric field sufficiently strong to cause tissue ablation, said antenna device being integrally formed by said inner conductor and said dielectric material medium extending beyond a distal portion of said outer conductor,
• wherein said dielectric material medium has a transverse cross-sectional dimension adapted for sliding receipt through said insert passage while said biopsy needle is positioned in the bio-tissue, and to a position advancing said antenna beyond said insert opening and further into said bio-tissue, and
• wherein said outer conductor has a transverse cross section dimension sized to prevent passage thereof through said access opening and into said insert passage in a manner contacting said biopsy needle to limit the advancement of said antenna beyond said insert opening, and to electrically couple to said biopsy needle such that said needle functions as a shield for the dielectric material medium and said inner conductor in said insert passage.

A method for ablating bio-tissue comprising:

• piercing an elongated probe into the bio-tissue percutaneously to a predetermined depth, said probe defining a passage extending therethrough from a proximal access end to an opposite distal end thereof;
• removing a specimen of bio-tissue through said biopsy needle;
• introducing into the passage an elongated microwave ablation device having a distal antenna coupled to a transmission line which in turn is coupled to a microwave energy source at a proximal end thereof;
• positioning the distal antenna at least at the probe distal end;
• and
• generating an electric field at the distal antenna which is sufficiently strong to cause ablation of the bio-tissue within the electric field.

A method of percutaneously ablating bio-tissue in a body cavity comprising:

• percutaneously piercing a penetration end of a biopsy needle into the bio-tissue to a predetermined depth from outside the body cavity, said biopsy needle defining an insert passage extending therethrough from an opposite access end to the penetration end thereof;
• removing a specimen of bio-tissue through said biopsy needle;
• inserting into the insert passage an elongated microwave ablation device having a distal antenna coupled to a transmission line which in turn is coupled to a microwave energy source at a proximal end thereof;
• advancing the distal antenna through said insert passage to a position beyond said penetration end and further into said bio-tissue;
• and
• generating an electric field at the distal antenna which is sufficiently strong to cause ablation of the bio-tissue within the electric field.

A microwave ablation assembly comprising:

• a conductive, elongated probe having a penetration end adapted to penetrate into bio-tissue and an opposite access end, said probe defining an insert passage extending therethrough from the access end to the penetration end thereof;
• a coaxial transmission line including an inner conductor and an outer conductor separated by a dielectric material medium, and having a proximal end coupled to a microwave energy source;
• and
• an antenna device for generating an electric field sufficiently strong to cause tissue ablation, said antenna device being integrally formed by said inner conductor and said dielectric material medium extending beyond a distal portion of said outer conductor, said dielectric material medium having a transverse cross-sectional dimension sized for sliding receipt through said insert passage, while said elongated probe is positioned in the bio-tissue, to a position advancing said antenna device beyond said penetration end and further into said bio-tissue;
• wherein said distal portion of said outer conductor is adapted to contact and to electrically couple to said biopsy needle such that said needle functions as a shield for the dielectric material medium and said inner conductor in said insert passage.

A method of percutaneously ablating bio-tissue in a body cavity comprising:

• providing a coaxial transmission line having a proximal end coupled to a microwave energy source, and having an inner conductor and an outer conductor separated by a dielectric material medium therebetween, a portion of said outer conductor being removed proximate a distal end of said transmission line to expose a portion of the dielectric material medium to form a distal said antenna device;
• percutaneously piercing a penetration end of a conductive biopsy needle into the bio-tissue to a predetermined depth from outside the body cavity, said biopsy needle defining an insert passage extending therethrough from an opposite access end to the penetration end thereof;
• inserting into the insert passage the distal antenna;
• advancing the distal antenna through said insert passage to a position beyond said penetration end and further into said bio-tissue;
• electrically connecting said outer conductor to said elongated probe causing the same to function as the transmission line and the antenna device;
• and
• generating an electric field at the distal antenna which is sufficiently strong to cause ablation of the bio-tissue within the electric field.

A method for ablating bio-tissue comprising:

• providing a coaxial transmission line having a proximal end coupled to a microwave energy source, and having an inner conductor and an outer conductor separated by a dielectric material medium therebetween, a portion of said outer conductor being removed proximate a distal end of said transmission line to expose a portion of the dielectric material medium to form a distal said antenna device;
• introducing a conductive, elongated probe into the bio-tissue to a predetermined depth, said probe defining a passage extending therethrough from a proximal access end to an opposite distal end thereof;
• introducing into the passage the distal antenna;
• positioning the distal antenna at least at the probe distal end;
• electrically connecting said outer conductor to said elongated probe causing the same to function as the transmission line and the antenna device;
• and
• generating an electric field at the distal antenna which is sufficiently strong to cause ablation of the bio-tissue within the electric field.