Radio-frequency generator for powering an ablation device

• US 7,074,217 B2
• Filed: 12/23/2002
• Issued: 07/11/2006
• Est. Priority Date: 05/08/1998
• Status: Expired due to Fees

• Current Assignee: Cytyc Surgical Products, LLC (Hologic Incorporated)
• Original Assignee: Cytyc Surgical Products II Incorporated (Hologic Incorporated)
• Inventors: Truckai, Csaba, Strul, Bruno, Kane, Mark Leo, Sampson, Russel Mahlon
• Primary Examiner(s): ROLLINS, ROSILAND STACIE
• Application Number:
  US10/328,447
• Publication Number:
  US 20030093070A1
• Time in Patent Office: 1,296 Days
• Field of Search: 128/898, 606/34, 606 37- 42, 606/45, 606/49, 606/46, 606/96, 606/98, 606/99, 606/101, 606/102, 606/115, 606/116
• US Class Current: 606/41
• CPC Class Codes: A61B 18/1206 Generators therefor
• CPC Class Codes: A61B 18/1485 having a short rigid shaft for accessing the inner body through natural openings
• CPC Class Codes: A61B 18/1492 having a flexible, catheter-like structure, e.g. for heart ablation A61B18/1477 takes precedence
• CPC Class Codes: A61B 2018/00214 Expandable means emitting energy, e.g. by elements carried thereon
• CPC Class Codes: A61B 2018/00559 Female reproductive organs
• CPC Class Codes: A61B 2018/00684 using lookup tables
• CPC Class Codes: A61B 2018/00702 Power or energy
• CPC Class Codes: A61B 2018/00761 Duration
• CPC Class Codes: A61B 2018/00779 Power or energy
• CPC Class Codes: A61B 2018/00875 Resistance or impedance
• CPC Class Codes: A61B 2018/00916 with means for switching or controlling the main function of the instrument or device
• CPC Class Codes: A61B 2018/124 switching the output to different electrodes, e.g. sequentially
• CPC Class Codes: A61B 2090/064 for measuring force, pressure or mechanical tension
• CPC Class Codes: A61B 2218/007 Aspiration

Abstract

An apparatus and method for use in performing ablation of organs and other tissues includes a radio frequency generator which provides a radio frequency signal to ablation electrodes. The power level of the radio frequency signal is determined based on the subject area of ablation. The radio frequency signal is coupled with the ablation electrodes through a transformation circuit. The transformation circuit includes a high impedance transformation circuit and a low impedance transformation circuit. The high or low impedance transformation circuit is selected based on the impedance of the ablation electrodes in contact with the subject tissue. Vacuum level, impedance level, resistance level, and time are measured during ablation. If these parameters exceed determinable limits the ablation procedure is terminated.

Claims

1. A method of ablating tissue comprising the steps of:

providing an RF ablation device and an RF generator system coupled to the ablation device, the RF generator system including an input device;

positioning the RF ablation device into contact with target tissue to be ablated;

using the input device, entering data corresponding to dimensions of the target tissue into the RF generator system;

causing the RF generator to automatically select an RF power based on the dimensions of the target tissue;

providing an RF signal at the selected RF power to the RF ablation device;

measuring a DC resistance of the RF ablation device; and

measuring an RF impedance of tissue in contact with the RF ablation device.

2. The method of claim 1, further comprising the step of generating an audio signal based upon the RF impedance of the tissue in contact with the RF ablation device.

3. The method of claim 1, wherein the step of measuring the RF impedance includes providing a low-power RF signal to the ablation device.

4. The method of claim 1, further comprising the step of maintaining the power of the RF signal substantially constant based upon the measured RF impedance of the tissue in contact with the ablation device.

5. The method of claim 1, further comprising the step of generating a fault if either of the DC resistance or the RF impedance falls outside a predetermined range.