Patent ID: 6042556
Filing Date: 2000-03-28
Classification: A61B,A61N

Abstract:
A method for applying ultrasound energy through a nonhomogeneous mass to an identified treatment volume to provide ultrasonic therapy to the treatment volume, wherein application of ultrasound energy causes molecular velocity fluctuation and pressure fluctuation along a path from a source of ultrasound energy to the treatment volume, and wherein there is a threshold intensity level at the treatment volume of the applied ultrasound energy, above which a relationship between the molecular velocity fluctuations and the pressure fluctuations becomes nonlinear in the treatment volume, the method comprising the steps of:configuring a first transducer array to define a first aperture, wherein the first transducer array is formed by a plurality of transducer elements;while the first transducer array is configured to define the first aperture, transmitting a pulse of ultrasound energy from the first transducer array toward the treatment volume at a prescribed frequency and at a first peak intensity greater than the threshold intensity level at the treatment volume;receiving echoes of the transmitted ultrasound energy at the first transducer array and at a second transducer array, the second transducer array having a plurality of transducer elements, wherein the echoes include ultrasound energy at a specific harmonic of the prescribed frequency;for echoes received during an expected time window for receiving echoes from the treatment volume, comparing arrival time phase of the received echoes at the specific harmonic for each active element of the first transducer array and the second transducer array;adjusting phase delay for received echoes for one or more elements of the second transducer array to achieve phase inversion; andwhile phase inversion is applied to the second transducer array, transmitting ultrasound energy from the second transducer array to the treatment volume at a second intensity for achieving desired ultrasonic medical therapy of the treatment volume, wherein the second intensity at the treatment volume is greater than the first peak intensity at the treatment volume.