Controlled high efficiency lesion formation using high intensity ultrasound

• US 20040030268A1
• Filed: 08/04/2003
• Published: 02/12/2004
• Est. Priority Date: 11/26/1999
• Status: Active Grant

• Current Assignee: Otsuka Medical Devices Co., Ltd. (Otsuka Holdings Company Limited)
• Original Assignee: Therus Corp. (Boston Scientific Corporation)
• Inventors: Zhang, Jimin, Perozek, David M., Weng, Lee
• Granted Patent: US 7,470,241 B2
• Time in Patent Office: Days
• US Class Current: 601/2
• CPC Class Codes: A61B 2017/4216 Operations on uterus, e.g. endometrium
• CPC Class Codes: A61B 2090/378 using ultrasound
• CPC Class Codes: A61B 8/12 in body cavities or body tracts, e.g. by using catheters catheters per se A61M25/00
• CPC Class Codes: A61B 8/4281 characterised by sound-transmitting media or devices for coupling the transducer to the tissue
• CPC Class Codes: A61B 8/445 Details of catheter construction
• CPC Class Codes: A61B 8/546 involving monitoring or regulation of device temperature
• CPC Class Codes: A61N 2007/0052 using the same transducer for therapy and imaging
• CPC Class Codes: A61N 7/00 Ultrasound therapy lithotripsy A61B17/22, A61B17/225; massage using supersonic vibration A61H23/00 ; using ultrasound for introducing media into the body A61M37/0092
• CPC Class Codes: A61N 7/02 Localised ultrasound hyperthermia hyperthermia in general A61F7/00
• CPC Class Codes: A61N 7/022 intracavitary

Abstract

An ultrasound system used for both imaging and delivery high intensity ultrasound energy therapy to treatment sites and a method for treating tumors and other undesired tissue within a patient'"'"'s body with an ultrasound device. The ultrasound device has an ultrasound transducer array disposed on a distal end of an elongate, relatively thin shaft. In one form of the invention, the transducer array is disposed within a liquid-filled elastomeric material that more effectively couples ultrasound energy into the tumor, that is directly contacted with the device. Using the device in a continuous wave mode, a necrotic zone of tissue having a desired size and shape (e.g., a necrotic volume selected to interrupt a blood supply to a tumor) can be created by controlling at least one of the f-number, duration, intensity, and direction of the ultrasound energy administered. This method speeds the therapy and avoids continuously pausing to enable intervening normal tissue to cool.

Claims

1. An ultrasonic system for destroying undesired tissue at an internal site within a body of a patient, comprising:

(a) a probe that is sized to be inserted within a body of a patient;

(b) an ultrasonic transducer mounted proximate a distal end of the probe, said ultrasonic transducer being adapted to couple to a power supply to selectively energize the ultrasonic transducer so that it produces a focused beam of high intensity ultrasonic energy; and

(c) an ultrasound transmissive interface that is coupled to the distal end of the probe, said ultrasound transmissive interface being disposed and adapted to conform to a surface of the undesired tissue and provide a liquid layer that more efficiently transmits the high intensity ultrasonic energy produced by the ultrasonic transducer into the undesired tissue, said high intensity ultrasonic energy increasing a temperature of the undesired tissue sufficiently to cause the undesired tissue to necrose.

2. The ultrasonic system of claim 1, wherein the ultrasound transmissive interface comprises an elastomeric cavity that is adapted to contain a liquid, said elastomeric cavity being disposed between the ultrasonic transducer and the surface of the undesired tissue so that the high intensity ultrasonic energy passes through the liquid within the elastomeric cavity and into the undesired tissue.

3. The ultrasonic system of claim 2, wherein the elastomeric cavity is formed at least in part from a semi-permeable membrane, so that the liquid from within the elastomeric cavity weeps onto a surface of undesired tissue to increase an efficiency for coupling the high intensity ultrasonic energy into the undesired tissue.

4. The ultrasonic system of claim 2, wherein the ultrasound transmissive interface comprises a cap made of an elastomeric material and disposed to surround the ultrasonic transducer, said cap being adapted to seal against the undesired tissue and to contain a liquid that increases an efficiency with which the high intensity ultrasonic energy is coupled into the undesired tissue.

5. The ultrasonic system of claim 4, wherein the cap includes a rim having a double lip formed around a perimeter and includes a passage adapted to couple to a vacuum line so that the rim of the cap is held against a surface of the undesirable tissue, sealing the liquid inside of the cap.

6. A method for administering an ultrasonic therapy to destroy at least a portion of an undesired tissue mass, comprising the steps of:

(a) providing an ultrasonic transducer that emits a focused high energy ultrasonic energy when energized;

(b) positioning the ultrasonic transducer proximate the undesired tissue mass;

(c) directing the-ultrasonic transducer toward a desired focal point within the undesired tissue mass;

(d) energizing the ultrasonic transducer so that it emits the focused high energy ultrasonic energy at the desired focal point, causing necrosis of a portion of the undesired tissue mass disposed at the desired focal point; and

(e) controlling at least one of an f-number, an intensity, a time, and a direction of the high intensity ultrasonic energy emitted into the undesired tissue mass to achieve a desired shape and size of a necrotic zone of undesired tissue destroyed as a result of being heated by the high intensity ultrasonic energy, said necrotic zone substantially blocking the high intensity ultrasonic energy from penetrating beyond the necrotic zone, said desired shape and size of the necrotic zone being selected and formed so as to cause substantially all of the undesired tissue mass to ultimately be destroyed.

7. The method of claim 6, wherein the step of controlling comprises the step of repositioning the ultrasonic transducer to direct the high intensity ultrasonic energy at a different portion of the undesired tissue mass, to achieve the desired shape and size of the necrotic zone.

8. The method of claim 6, wherein the desired shape and size of the necrotic zone are selected so that formation of the necrotic zone substantially deprives the undesired tissue mass of a blood supply, cause the ultimate destruction of the undesired tissue mass.

9. The method of claim 6, wherein the desired shape and size of the necrotic zone are selected to control bleeding at a treatment site.