Catheter based balloon for therapy modification and positioning of tissue

Abstract

An apparatus and method for shielding non-target tissues and organs during thermotherapy, brachytherapy or other treatment of a diseased target tissue. The apparatus includes a catheter shaft having input and output lumens and at least one inflatable balloon. A plurality of input lumens within the catheter shaft allows the passage of liquid or gas through an input port and into the interior of the balloon thereby inflating the balloon. The gas or liquid can then be cycled through the inflated balloon through an output port and output lumen and out of the catheter shaft. Temperature sensors or other sensors may be attached to the balloon or catheter to monitor temperature or other conditions at the treatment site. The catheter is positioned between the target tissue or organ and sensitive non-target tissues in proximity to the target tissue and inflated causing a physical separation of tissues as well as a physical shield.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a divisional of U.S. application Ser. No. 10 / 756,588 filed on Jan. 12, 2004, now U.S. Pat. No. ______, incorporated herein by reference in its entirety, which is a divisional of U.S. application Ser. No. 10 / 020,583 filed on Dec. 14, 2001, now U.S. Pat. No. 6,746,465, incorporated herein by reference in its entirety.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT[0002]Not ApplicableINCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC[0003]Not ApplicableNOTICE OF MATERIAL SUBJECT TO COPYRIGHT PROTECTION[0004]A portion of the material in this patent document is subject to copyright protection under the copyright laws of the United States and of other countries. The owner of the copyright rights has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the United States Patent and Trademark Office publicly available file or recor...

AI Technical Summary

Benefits of technology

[0028]In one embodiment, either a gas or a fluid with an acoustic mismatch from surrounding tissue or an acoustic absorber is used to inflate the balloon(s) and thereby modify the acoustic transmission and reflective characteristics between the tissue and the device.

[0033]The catheter material may be hard or soft or rigid or flexible depending on the desired application. The tip of the stiff catheter may be sharp to allow for the direct insertion into tissue. The catheter tip may also be blunt and may be configured for placement with a removable stiffener or introducer. Flexible material such as silicone will allow for a longer duration implantation and longer balloon deployment such as with permanent seed implant.

[0036]Another object of the invention is to provide an apparatus and method of blocking the exposure of sensitive surrounding tissues to acoustic energy from the target tissue.

Problems solved by technology

For exposures at comparatively longer times or higher temperatures, cellular repair mechanisms can no longer keep up or lose function due to the thermal damage of key enzymes, and cell death and tissue necrosis will occur within 3 to 5 days.

These thermal effects are lethal and immediate, producing thermally coagulated (dead) tissue.

However, the efficacy of these treatment modalities may be limited due to inadequacy in protecting sensitive non-targeted tissues or adequately treating a large enough of a volume of tissue.

Presently, treating the prostate gland with heat is problematic.

If properly positioned within the prostatic urethra, these devices can thermally destroy a region within the center of the prostate, which leads to a reduction of BPH symptoms.

Although moderately effective for treatment of BPH, these devices are not effective for treating prostate cancer, which mostly involves tissues away from the urethra in the posterior portion of the gland, often adjacent to critical nerves and the rectum.

In order to treat large distances from the urethra, higher amounts of energy and greater temperatures are required, leading to damage of the rectum or surrounding non-targeted tissues.

Transrectal focused ultrasound devices (HIFU) offer some spatial control but treating the most dorsal portion of the prostate is still problematic, due to the risk of thermal damage to the rectum.

The amount of heating power, temperature distributions, and applicator placement are often limited in the treatment of these diseases by the need to protect sensitive non-targeted tissues.

Thus it can be seen that the usefulness and efficacy of thermal therapies are limited by the sensitivity to thermal exposure of associated non-target tissues.

The usefulness and efficacy of treatments other than thermal therapy, such as interstitial and external beam radiation therapies, may also be limited by the collateral damage to non-target tissues that can occur with these therapies.

However, proper placement of the HDR catheters is critical because of the high dosages of radiation involved.

Unfortunately, the imprecise placement of radiation sources can still occur with the use of ultrasound due to the proximity of the bladder and rectum and associated structures to the prostate gland.

For many cases, especially treatment of a previously radiated recurrence, the total radiation dose that can be applied is limited due to the exposure limits on normal tissue structures that are close to the prostate gland such as the rectum, bladder and urethra.

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