Abstract: Apparatus, systems, and methods are provided for measuring the power of acoustic energy transmitted by an ultrasound transducer. The apparatus includes a container including a liquid therein, and a buoyant body floating at a first level in the liquid. When acoustic energy is transmitted by the ultrasound transducer towards the buoyant body, the buoyant body floats at a second, different level in the liquid. The displaced volume of the buoyant body from the first level to the second level is directly related to the power of the acoustic energy transmitted by the ultrasound transducer. The apparatus may output signals corresponding to the level at which the buoyant body floats. The signal may be routed to a controller for adjusting the power output by the ultrasound transducer.

Abstract: A system for performing a therapeutic procedure using focused ultrasound includes a piezoelectric transducer, drive circuitry coupled to the transducer for providing drive signals to the transducer, and a controller coupled to the drive circuitry for alternating an intensity of the drive signals between a plurality of intensities. Acoustic energy above a threshold intensity is transmitted by the transducer towards a target region to generate microbubbles in tissue within the target region. The intensity of the acoustic energy is reduced to discontinue generating microbubbles and heat the tissue, e.g., to necrose the tissue, without collapsing the generated microbubbles, the microbubbles enhancing the ability of the tissue in the target region to absorb the acoustic energy.

Abstract: Systems and methods are provided for positioning a therapy device, such as an ultrasound transducer, using a tilt sensor carried by the transducer and a positioner coupled to the transducer. The positioner provides roll and pitch control as well as translating the transducer in lateral and longitudinal directions. A processor receives signals from the tilt sensor corresponding to the actual rotational orientation of the transducer and controls the positioner to adjust the orientation of the therapy device until a desired position is achieved.

Abstract: Apparatus, systems, and methods are provided for measuring the power of acoustic energy transmitted by an ultrasound transducer. The apparatus includes a container including a liquid therein, and a buoyant body floating at a first level in the liquid. When acoustic energy is transmitted by the ultrasound transducer towards the buoyant body, the buoyant body floats at a second, different level in the liquid. The displaced volume of the buoyant body from the first level to the second level is directly related to the power of the acoustic energy transmitted by the ultrasound transducer. The apparatus may output signals corresponding to the level at which the buoyant body floats. The signal may be routed to a controller for adjusting the power output by the ultrasound transducer.

Abstract: A method for sensing a disturbance in a transmission path of a converging ultrasound energy beam transmitted by a transducer in a focussed ultrasound system comprises transmitting a burst of ultrasound energy from the transducer, detecting whether a reflected portion of the ultrasound energy burst is received at the transducer within a certain time period following transmission of the burst, and, if so, analyzing the received reflected portion to determine a characteristic of the disturbance.

Abstract: Systems and methods for testing the performance of a focused ultrasound transducer array include transmitting ultrasonic energy from the transducer array towards an acoustic reflector, such as a planar air mirror, and receiving ultrasonic energy reflected off of the acoustic reflector using a sensing element. A characteristic of the reflected ultrasonic energy, such as amplitude and phase, is measured by processing circuitry, for example, by comparing the characteristic of the received ultrasonic energy to a corresponding characteristic of the transmitted ultrasonic energy to obtain an actual gain and phase shift for the received ultrasonic energy. A controller compares the actual gain and phase shift of the received ultrasonic energy to an expected gain and phase shift of the received ultrasonic energy. This information is used to calibrate the transducer array and/or to declare a system failure if the comparison indicates an error.

Abstract: Systems and methods using magnetic resonance imaging for monitoring the temperature of a tissue mass being heated by energy converging in a focal zone that is generally elongate and symmetrical about a focal axis. A first plurality of images of the tissue mass are acquired in a first image plane aligned substantially perpendicular to the focal axis. A cross-section of the focal zone in the first image plane is then defined from the first plurality of images. A second plurality of images are acquired of the tissue mass in a second image plane aligned substantially parallel to the focal axis, the second image plane bisecting the first image plane at approximately a midpoint of the defined focal zone cross-section.

Abstract: Magnetic resonance temperature change monitoring of a heated portion of a tissue mass undergoing thermal treatment is more accurately accomplished by compensating for false temperature change measurements caused by movement of the mass and/or temporal changes of the magnetic field during the thermal MR Imaging, wherein the compensation is based on subtracting out “apparent temperature change” measurements of one or more unheated portions of the tissue mass located in a neighborhood of the heated portion, which form a temperature bias map of the tissue mass region.

Abstract: System and methods for performing a therapeutic procedure using focused ultrasound include providing a piezoelectric transducer including a plurality of transducer elements, such as a concave concentric ring array or a liner array of transducer elements. Drive circuitry is coupled to the transducer for providing drive signals to the transducer elements at one of a plurality of discrete RF frequencies. A controller is coupled to the drive circuitry for periodically changing a frequency of the drive signals to one of the plurality of discrete frequencies, while controlling a phase component of the drive signals to maintain the focus of the transducer at a primary focal zone during a single sonication.