Solid hydrogel coupling for ultrasound imaging and therapy

Abstract

The present invention employs hydrogels as acoustic couplings for clinical applications of ultrasound imaging and therapy, but is particularly applicable to high intensity focused ultrasound (HIFU) based therapy. While other materials can be used, it has been determined that polyacrylamide is sufficiently robust and transmissive to withstand the high temperatures encountered in HIFU therapy. One embodiment of a hydrogel coupling is configured in shape and size (length) to ensure that a focal region of an ultrasound transducer is disposed proximate the target area when the distal tip of the transducer is in contact with tissue. These couplings can be shaped to correspond to the beam focus characteristics of specific transducers. Water can be applied to hydrate the tip of the hydrogel coupling during use, and medication absorbed into the hydrogel material can be applied to the tissue in contact with the distal surface of the hydrogel.

Description

RELATED APPLICATIONS [0001] This application is a divisional application based on prior copending application Ser. No. 10 / 449,819 filed May 30, 2003, which itself is based on a prior copending provisional application, Ser. No. 60 / 384,566, filed on May 30, 2002, the benefit of the filing dates of which is hereby claimed under 35 U.S.C. §§ 119(e) and 120.GOVERNMENT RIGHTS [0002] The research for this invention was funded with grants from the National Institutes of Health (No. 5R01-HL064208-02) and from the Department of the Navy (No. N00014-96-1-0630). The U.S. government may have certain rights in this invention.FIELD OF THE INVENTION [0003] The present invention generally relates to a hydrogel based coupling for use in ultrasonic imaging and therapy, and method for use of the same, and more specifically, pertains to a dimensionally stable hydrogel that remains stable when transmitting relatively high intensity ultrasound to a therapy site, and a method for using the same. BACKGROUND...

AI Technical Summary

Benefits of technology

The present invention is directed to a hydrogel coupling that is used to acoustically couple an ultrasound transducer with a target, such as a patient's skin or a sub-dermal area. The hydrogel coupling is designed to be placed between the transducer and the target, or between the transducer and a physical boundary associated with the target. The hydrogel coupling is stable, meaning it can maintain its structure even when exposed to acoustic energy generated by the transducer. The hydrogel coupling can be easily replaced with another hydrogel coupling, and it is transparent to allow for easy visual verification of the target. The hydrogel coupling is formed from a polymer material and can be made from poly(2-hydroxyethyl methacrylate). The technical effect of the invention is to provide a reliable and flexible tool for ultrasound imaging that can be easily used in medical applications.

Problems solved by technology

Many studies have shown that these sound waves are harmless and may be used with complete safety, even to visualize the fetus in pregnant women, where the use of X-rays would be inappropriate.

While the treatment was quite successful, monitoring and guidance of the HIFU lesion formation was not easily achieved (as reported by N. T. Sanghvi and R. H. Hawes, (1994) “High-intensity focused ultrasound,”Gastrointestinal Endoscopy Clinics of North America, 4: 383-95).

While this coupling method has been useful for hemostasis experiments, it has many drawbacks that would make it impractical for a clinical setting.

These disadvantages include degassing, sterilization, circulation, and containment issues.

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