Mechanically scanned line-focus ultrasound hyperthermia system

• US 4,938,216 A
• Filed: 06/21/1988
• Issued: 07/03/1990
• Est. Priority Date: 06/21/1988
• Status: Expired due to Fees

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Lele, Padmakar P.
• Primary Examiner(s): Cohen, Lee S.
• Application Number:
  US07/209,519
• Time in Patent Office: 742 Days
• Field of Search: 128/399, 128/24 A, 128/660.03, 128/660.09, 128/663.01, 73/642, 73/618
• US Class Current: 601/3
• CPC Class Codes: A61N 2007/006 Lenses
• CPC Class Codes: A61N 7/02 Localised ultrasound hyperthermia hyperthermia in general A61F7/00

Abstract

A therapeutic hyperthermia system generates a line-focus beam of ultrasound which can be mechanically scanned across a treatment volume of tissue. The ultilization of a line-focus advantageously reduces the peak intensity of the ultrasonic beam. The system includes methods of scanning the line-focus beam to provide optimal treatment protocols for deep tumors and other pathological conditions while minimizing damage in overlying body tissues. The utilization of mechanical scanning reduces the number of transducers, amplifiers and associated electronics required.

Claims

1. An ultrasonic hyperthermia system for delivering hyperthermic therapy to a subject, the system comprising

a piezoelectric transducer element which can produce a beam of ultrasonic energy upon electrical activation, said piezoelectric transducer element having a selected length and a substantially constant thickness over said length;

a line-focus lens element coupled with the transducer element and adapted to be situated between the transducer element and the subject, for focusing a beam of ultrasonic energy produced by said transducer element upon electrical activation into a substantially linear focal region, said substantially linear focal region having a length substantially equal to the length of the transducer element;

electrical activation means for activating the transducer element, the electrical activation means including adjustment means for selectively varying the electrical excitation, and, as a result, the intensity of the ultrasonic energy beam, the adjustment means including means for selectively varying the intensity of the ultrasonic energy beam continuously across the substantially linear focal region; and

scanning means for scanning the line-focused beam across a target region of a subject during activation of the transducer element.

2. The system of claim 1 wherein the line-focus lens element is a cylindrical lens.

3. An ultrasonic hyperthermia system for delivering hyperthermic therapy to a subject, the system comprising

a piezoelectric transducer element which can produce a beam of ultrasonic energy upon electrical activation;

a line-focus lens element coupled with the transducer element and adapted to be situated between the transducer element and the subject, for focusing a beam of ultrasonic energy produced by said transducer element upon electrical activation into a substantially linear focal region;

electrical activation means for activating the transducer element, the electrical activation means including adjustment means for selectively varying the electrical excitation, and, as a result, the intensity of the ultrasonic energy beam, the adjustment means including means for selectively varying the intensity of the ultrasonic energy beam continuously across the substantially linear focal region; and

scanning means for scanning the line-focused beam across a target region of a subject during activation of the transducer element, the scanning means including means for scanning the ultrasonic energy beam across said target region in a non-linear pattern.

4. The system of claim 3 wherein the means for scanning in a non-linear pattern includes a rotational means for rotating the line-focused beam to provide non-linear scanning.

5. The system of claim 4 wherein the scanning means further includes translational means for changing the focal depth within the tissue as the line-focused beam is rotated.

6. An ultrasonic hyperthermia method for delivering hyperthermic therapy to a subject, the method comprising the steps of:

configuring a piezoelectric transducer element to have a selected length and a substantially constant thickness over said length and to produce a beam of ultrasonic energy upon electrical activation;

orienting a line-focus lens element to focus a beam of ultrasonic energy produced by said transducer element upon activation into a substantially linear focal region having a length substantially equal to the length of the transducer element;

electrically activating the transducer element to produce the beam of ultrasonic energy, the activating step including the step of selectively varying the electrical activation, and as a result, the intensity of the ultrasonic energy beam, the varying step including the step of selectively varying the intensity of the ultrasonic energy beam continuously across the substantially linear focal region; and

scanning the line-focused beam across a target region of a subject during activation of the transducer element.

7. The method of claim 6 wherein the orienting step includes the step of orienting a cylindrical lens to focus the beam into a line-focus.

8. An ultrasonic hyperthermia method for delivering hyperthermic therapy to a subject, the method comprising the steps of:

configuring a piezoelectric transducer element to produce a beam of ultrasonic energy upon electrical activation;

orienting a line-focus lens element to focus a beam of ultrasonic energy produced by said transducer element upon activation into a substantially linear focal region;

electrically activating the transducer element to produce the beam of ultrasonic energy, the activating step including the step of selectively varying the electrical activation, and as a result, the intensity of the ultrasonic energy beam, the varying step including the step of selectively varying the intensity of the ultrasonic energy beam continuously across the substantially linear focal region; and

scanning the line-focused beam across a target region of a subject during activation of the transducer element, the scanning step including the step of scanning the line-focus beam in a non-linear scanning pattern.

9. The method of claim 8 wherein the scanning step further includes the step of rotating the line-focused beam to provide non-linear scanning.

10. The method of claim 9 wherein the scanning step further includes the step of translating the line-focused beam for changing the focal depth within the tissue as the line-focused beam is rotated.