RF treatment apparatus

Abstract

An RF treatment apparatus includes a catheter with a catheter lumen. A removable needle electrode is positioned in the catheter lumen in a fixed relationship to the catheter. The needle electrode includes a needle lumen and a needle electrode distal end. A removable introducer is slidably positioned in the needle lumen. The introducer includes an introducer distal end. A first sensor is positioned on a surface of the needle electrode or the insulator. An RF power source is coupled to the needle electrode and a return electrode. An insulator sleeve is slidably positioned around the electrode and includes a second sensor. Resources are associated with the electrodes, sensors as well as the RF power source for maintaining a selected power at the electrode independent of changes in current or voltage.

Description

CONTINUING APPLICATION DATA [0001] This application is a continuation-in-part of U.S. patent application Ser. No. 08 / 148,439 entitled “DEVICE FOR TREATING CANCER AND NON-MALIGNANT TUMORS AND METHODS”, by Edwards et al. which is incorporated herein by reference.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] This invention relates generally to an apparatus for the treatment and ablation of body masses, such as tumors, and more particularly, to an RF treatment system suitable for multi-modality treatment with an infusion delivery device, catheter, removable electrode, insulator sleeve and introducer, all housed in the catheter. The system maintains a selected power at an electrode what is independent of changes in current or voltage. [0004] 2. Description of the Related Art [0005] Current open procedures for treatment of tumors are extremely disruptive and cause a great deal of damage to healthy tissue. During the surgical procedure, the physician must exercise car...

AI Technical Summary

Benefits of technology

[0017] Another object of the invention is to provide an RF treatment apparatus which has a catheter insert with interchangeable introducers and electrodes, and resources to maintain the electrode at a selected power irrespective of changes in current or voltage.

[0025] With the RF treatment apparatus of the invention, an insert or treatment needle is removably attached to a catheter and positioned in the catheter lumen, or the catheter is removably attached to the infusion device and positioned in the infusion device lumen. An introducer can be slidably positioned in the insert lumen initially, to assist in the introduction of the catheter and insert into a body structure. The introducer is then removed and the treatment needle substituted in its place. Temperature readings are taken adjacent to the tissue site in the vicinity of the electrode. Resources control the amount of energy supplied to the treatment site so that RF energy is delivered at low enough power so that the tissue at the electrode is not desiccated, but sufficient enough to kill the cells of the tumor.

[0027] Hardware and software, collectively “resources” maintain a selected power at the electrode include a power supply, power circuits, controller, user interface and display, a device to calculate power and impedance, current and voltage sensors and a temperature measurement device. The controller can be under microprocessor control. Imaging of the tumor, through ultrasound, CT scanning, and the like, can be utilized to first define the boundaries of the tumor mass. Images of the tumor are then imported to a display. Individual electrode needles are thereafter positioned in or surround the tumor, and RF energy is then slowly delivered to the tumor. Prior treatment planning of the tumor assists in the effective delivery of RF treatment energy. Through imaging, tissue characterization by monitoring the process, is achieved. The electrodes are used in the bipolar mode.

[0028] An electrode can be removed from the catheter and placed at a different location than the catheter to measure temperature, and deliver RF energy. Multiple electrodes are introduced through their respective catheters to tumor sites. Tumor sites are treated, through hyperthermia or ablation, selectively through the controlled delivery of RF energy. Temperature is monitored, and through the resources, a selected level of power is maintained independent of changes in voltage or current. A variety of different devices can be positioned and removed in the catheter. These include, introducers and electrodes. The treatment device of the invention permits a wide range of tumor treatment devices to be introduced to the tumor site for multi-modality evaluation and treatment purposes. The catheter or infusion device can remain positioned at the tumor site for an extended period for later treatment of RF energy or introduction of a chemotherapeutic agent.

Problems solved by technology

Current open procedures for treatment of tumors are extremely disruptive and cause a great deal of damage to healthy tissue.

During the surgical procedure, the physician must exercise care in not cutting the tumor in a that creates seeding of the tumor, resulting in metastasis.

Among the problems associated with all of these procedures is the requirement that highly localized heat be produced at depths of several centimeters beneath the surface of the body.

However, the extent of localization is generally poor, with the result that healthy tissue may be harmed.

Induction heating gives rise to poor localization of the incident energy as well.

Although induction heating may be achieved by placing an antenna on the surface of the body, superficial eddy currents are generated in the immediate vicinity of the antenna, when it is driven using RF current, and unwanted surface heating occurs with little heating delivered to the underlying tissue.

Thus, non-invasive procedures for providing heat to internal tumors have had difficulties in achieving substantial specific and selective treatment.

In thermotherapy, heat energy of greater than 45 degrees C. is applied, resulting in histological damage, desiccation and the denaturization of proteins.

It is difficult to externally induce hyperthermia in deep body tissue because current density is diluted due to its absorption by healthy tissue.

Additionally, a portion of the RF energy is reflected at the muscle / fat and bone interfaces which adds to the problem of depositing a known quantity of energy directly on a small tumor.

Attempts to use interstitial local hyperthermia have not proven to be very successful.

This process has been difficult to achieve due to a variety of factors including, (i) positioning of the RF ablation electrodes to effectively ablate all of the mass, (ii) introduction of the RF ablation electrodes to the tumor site and (iii) controlled delivery and monitoring of RF energy to achieve successful ablation without damage to non-tumor tissue.

Different size tumors can not be treated with the same electrode.

The device of the '671 patent fails to provide for the introduction of a fluidic medium, such as a chemotherapeutic agent, to the tumor for improved treatment.

Additionally, the device of the '671 patent is not capable of maintaining a preselected level of power that is independent of changes in voltage or current.

The device of the '200 patent is limited in that the single entrance tract fails to provide for the introduction, and removal of a variety of inserts, including but not limited to an introducer, fluid infusion device and insulation sleeve.

Additionally, the device of the '200 patent fails to provide for the maintenance of a selected power independent of changes in current or voltage.

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