Electronically-controlled variable focus ultrasound hyperthermia system

• US 4,938,217 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:
  US07/209,517
• Time in Patent Office: 742 Days
• Field of Search: 128/24 A, 128/399, 128/660.03, 128/660.09, 73/618
• US Class Current: 601/3
• CPC Class Codes: A61B 2017/22028 arrays, e.g. phased arrays
• CPC Class Codes: A61N 2007/0095 by modifying an excitation signal
• CPC Class Codes: A61N 7/02 Localised ultrasound hyperthermia hyperthermia in general A61F7/00

Abstract

A therapeutic ultrasound hyperthermia system utilizes a phased array of ultrasound transducer elements. By varying the phase delays in the excitation of individual transducer elements, the focal depth of the ultrasonic beam can be varied, without changing the distance between the transducer and the patient. The phased array of transducer elements can be an array of rectangular elements which are rotated about an axis to deliver ultrasound to the target region while minimizing overall heating effect in the treatment areas outside the target region.

Claims

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

ultrasonic transducer means, including a plurality of piezoelectric transducer elements, said transducer elements having a substantially constant thickness, said transducer elements being arranged in an array to provide multiple sources of ultrasonic energy, for generating a beam of ultrasonic energy characterized by an elongate, substantially linear focal region or selected length at a selected depth in the subject;

an electrical excitation means for exciting said transducer elements, said electrical excitation means including electronic control means for dynamically and electronically varying the length and depth of the substantially linear focal region, said electronic control means including a phase-shifting means for supplying the transducer elements with electrical excitations having adjustable phases for dynamically varying the length and depth of the substantially linear focal region to selectively focus the beam of ultrasonic energy from the transducer array into a target region of treatment area within the subject; and

scanning means for scanning the focused ultrasonic energy across said target region.

2. The system of claim 1 further comprising means for supplying the transducer elements with electrical excitations having selected amplitudes.

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

ultrasonic transducer means, including a plurality of piezoelectric transducer elements arranged in an array to provide multiple sources of ultrasonic energy, for generating a beam of ultrasonic energy characterized by a substantially linear focal region of selected length at a selected depth in the subject;

an electrical excitation means for exciting said transducer elements, said electrical excitation means including electronic control means for dynamically and electronically varying the length and depth of the substantially linear focal region, said electronic control means including a phase-shifting means for supplying the transducer elements with electrical excitations having adjustable phases for dynamically varying the length and depth of the substantially linear focal region to selectively focus the beam of ultrasonic energy from the transducer array into a target region of treatment area within the subject; and

scanning means for scanning the focused ultrasonic energy across said target region, the scanning means including means for scanning the focused ultrasonic energy across said target region in a non-linear pattern.

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

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

arranging a plurality of piezoelectric transducer elements having a substantially constant thickness in an array to provide multiple sources of ultrasonic energy;

exciting said transducer elements to generate a beam of ultrasonic energy characterized by an elongate, substantially linear focal region of selected length at a selected depth in the subject, said exciting step including the step of supplying the transducer elements with electrical excitations having adjustable phases for dynamically and electronically varying the length and depth of the substantially linear focal region, to selectively focus the beam of ultrasonic energy from the transducer array into a target region of treatment area within a subject; and

scanning the focused ultrasonic energy across the target region.

6. The method of claim 5 wherein the exciting step includes the step of supplying the transducer elements with electrical excitations having selected amplitudes.

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

arranging a plurality of piezoelectric transducer elements in an array to provide multiple sources of ultrasonic energy;

exciting said transducer elements to generate a beam of ultrasonic energy characterized by a substantially linear focal region of selected length at a selected depth in the subject, said exciting step including the step of supplying the transducer elements with electrical excitations having adjustable phases for dynamically and electronically varying the length and depth of the substantially linear focal region, to selectively focus the beam of ultrasonic energy from the transducer array into a target region of treatment area within a subject; and

scanning the focused ultrasonic energy across said target region, the scanning step including the step of scanning the focused ultrasonic energy in a non-linear pattern.

8. The method of claim 7 wherein the non-linear scanning step includes the step of rotating the focused ultrasonic energy beam to provide the non-linear scanning.