Apparatus and method for acoustic heat generation and hyperthermia

A method for heating a target with ultrasound, comprising the steps of

• producing a first focused ultrasound beam having a frequency f.sub.0 between about 50 kHz and 5 MHz with a first ultrasound hyperthermia source;
• producing a second focused ultrasound beam having a frequency f.sub.1 between about 50 kHz and 5 MHz with a second ultrasound hyperthermia source;
• directing the first and second focused ultrasound beams at the target to be heated so that the first and second ultrasound beams cross each other at the target, and the focus of the first and second ultrasound beams are substantially coincident where the beams cross;
• wherein
• the first and second ultrasonic beams have sufficient ultrasound energy to produce intermodulation products at the target where the first and second ultrasound beams cross, and wherein the intermodulation products include integral multiples of sum-frequencies f.sub.0 +f.sub.1 which are absorbed by the target to provide additional heat to the target and the intermodulation products are highly absorbed by the target at a substantially greater rate than ultrasound energy having a frequency of either f.sub.0 or f.sub.1 or a linear superposition of f.sub.0 and f.sub.1.

An ultrasound hyperthermia applicator for heating a target, comprising

• a plurality of N ultrasound hyperthermia source means which each produces an ultrasound energy having a corresponding frequency f.sub.n between about 50 kHz and 5 MHz, where n is from 1 to N;
• a plurality of focusing means which each focuses the energy from a different one of the hyperthermia source means and produces one of N focused ultrasound beams for heating the target;
• aiming means for directing the N focused ultrasound beams at the target to be heated so that the N ultrasound beams cross each other at the target, and the focus of each of the N ultrasound beams are substantially coincident where the beams cross;
• and
• control means for activating the N ultrasound hyperthermia source means to provide simultaneous irradiation of the target by each of the N focused ultrasound beams to heat the target;
• wherein the N ultrasound hyperthermia source means provide sufficient ultrasound energy for producing intermodulation products at the target where the N ultrasound beams cross, and wherein the intermodulation products include integral multiples of sum frequencies of the corresponding frequencies f.sub.n which are absorbed by the target to provide additional heat to the target and the intermodulation products are highly absorbed by the target at a substantially ultrasound energy having a frequency of of f.sub.n or a linear superposition of f.sub.n.

An ultrasound hyperthermia applicator for heating a target, comprising

• first ultrasound hyperthermia source means for producing ultrasound energy having a frequency f.sub.0 between about 50 Khz and 5 Mhz;
• first focusing means for focusing the energy from the first ultrasound hyperthermia source means and for producing a first focused ultrasound beam for heating the target;
• second ultrasound hyperthermia source means for producing ultrasound energy having a frequency f.sub.1 between about 50 Khz and 5 Mhz;
• second focusing means for focusing the energy from the second ultrasound hyperthermia source means and for producing a second focused ultrasound beam for heating the target;
• aiming means for directing the first and second focused ultrasound beams at the target to be heated so that the first and second ultrasound beams cross each other at a plurality of selectable points within a three-dimensional region which includes the target, and the focus of the first and the second ultrasound beams are substantially coincident at the plurality of selectable points where the beams cross;
• and
• control means for activating the first and second ultrasound hyperthermia source means to provide simultaneous irradiation of the target by each of the first and second focused ultrasound beams to heat the target at the plurality of selectable points;
• wherein the first and second ultrasound hyperthermia source means provide sufficient ultrasound energy for producing intermodulation products at the plurality of selectable points where the first and second focused ultrasound beams cross, and wherein the intermodulation products include integral multiples of sum-frequencies f.sub.0 +f.sub.1 which are absorbed by the target at the plurality of selectable points to provide additional heat to the target and the intermodulation products are highly absorbed by the target at a substantially greater rate than ultrasound energy having a frequency of either f.sub.0 or f.sub.1 or a linear superposition of f.sub.0 and f.sub.1.

An ultrasound hyperthermia applicator for heating a target, comprising

• first ultrasound hyperthermia source means for producing ultrasound energy which is a triangular wave broadband signal rich in harmonics of a fundamental frequency f.sub.0 between about 50 Khz and 5 Mhz;
• first focusing means for focusing the energy from the first ultrasound hyperthermia source means and for producing a first focused ultrasound beam for heating the target;
• second ultrasound hyperthermia source means for producing ultrasound energy which is a triangular wave broadband signal rich in harmonics of a fundamental frequency f.sub.1 ;
• second focusing means for focusing the energy from the second ultrasound hyperthermia source means and for producing a second focused ultrasound beam for heating the target;
• aiming means for directing the first and second focused ultrasound beams at the target to be heated so that the first and second ultrasound beams cross each other at the target, and the focus of the first and the second ultrasound beams are substantially coincident where the beams cross;
• and
• control means for activating the first and second ultrasound hyperthermia source means to provide simultaneous irradiation of the target by each of the first and second focused ultrasound beams to heat the target;
• wherein the first and second ultrasound hyperthermia source means and provide broadband signals which are rich in harmonics for producing a similarly rich variety of intermodulation products at the target where the first and second focused ultrasound beams cross, and wherein the intermodulation products include integral multiples of sum-frequencies f.sub.0 +f.sub.1 which are easily absorbed by the target to provide additional heat to the target and the intermodulation products are highly absorbed by the target at a substantially greater rate than ultrasound energy having a frequency of either f.sub.0 or f.sub.1 or a linear superposition of f.sub.0 and f.sub.1.

An ultrasound hyperthermia applicator for heating a target, comprising

• first ultrasound hyperthermia source means for producing ultrasound energy having a frequency f.sub.0 between about 50 Khz and 5 Mhz;
• first focusing means for focusing the energy from the first ultrasound hyperthermia source means and for producing a first focused main ultrasound beam for heating the target;
• second ultrasound hyperthermia source means for producing ultrasound energy having a frequency f.sub.1 between about 50 Khz and 5 Mhz;
• second focusing means for focusing the energy from the second ultrasound hyperthermia source means and for producing a second focused main ultrasound beam for heating the target;
• aiming means for directing the first and second focused main ultrasound beams at the target to be heated so that the first and second main ultrasound beams cross each other at the target, and the focus of the first and the second main ultrasound beams are substantially coincident where the main beams cross;
• and
• control means for activating the first and second ultrasound hyperthermia source means to provide simultaneous irradiation of the target by each of the first and second focused main ultrasound beams to heat the target;
• wherein the first and second ultrasound hyperthermia source means provide ultrasound energy sufficient for producing intermodulation products at the target where the first and second focused main ultrasound beams cross, and wherein the intermodulation products include integral multiples of sum-frequencies f.sub.0 +f.sub.1 which are absorbed by the target to provide additional heat to the target and the intermodulation products are highly absorbed by the target at a substantially greater rate than ultrasound energy having a frequency of either f.sub.0 or f.sub.1 or a linear superposition of f.sub.0 and f.sub.1.

An ultrasound hyperthermia applicator for heating a target, comprising

• first ultrasound hyperthermia source means for producing ultrasound energy which is a modulated signal centered about a frequency f.sub.0 between about 50 Khz and 5 Mhz, wherein the modulation is in the form of amplitude modulation, frequency modulation, or pseudo-random modulation;
• first focusing means for focusing the energy from the first ultrasound hyperthermia source means and for producing a first focused ultrasound beam for heating the target;
• second ultrasound hyperthermia source means for producing ultrasound energy which is a modulated signal centered about a frequency f.sub.1 between about 50 Khz and 5 Mhz, wherein the modulation is in the form of amplitude modulation, frequency modulation, or pseudo-random modulation;
• second focusing means for focusing the energy from the second ultrasound hyperthermia source means and for producing a second focused ultrasound beam for heating the target;
• aiming means for directing the first and second focused ultrasound beams at the target to be heated so that the first and second ultrasound beams cross each other at the target, and the focus of the first and the second ultrasound beams are substantially coincident where the beams cross;
• and
• control means for activating the first and second ultrasound hyperthermia source means to provide simultaneous irradiation of the target by each of the first and second focused ultrasound beams to heat the target;
• wherein the first and second ultrasound hyperthermia source means provide and ultrasound energy sufficient for producing intermodulation products at the target where the first and second focused ultrasound beams cross, and wherein the intermodulation products include integral multiples of sum-frequencies f.sub.0 +f.sub.1 which are absorbed by the target to provide additional heat to the target and the intermodulation products are highly absorbed by the target at a substantially greater rate than ultrasound energy having a frequency of either f.sub.0 or f.sub.1 or a linear superposition of f.sub.0 and f.sub.1.