Abstract: A method for treating body tissue using acoustic energy includes identifying a target focal zone of tissue to be treated, delivering a first pulse of acoustic energy from a transducer to generate bubbles in a tissue region located distally, relative to the transducer, of a focal center of the target focal zone, and delivering a second pulse of acoustic energy from the transducer in the presence of the bubbles generated by the first pulse, the second pulse focused at the focal center to generate thermal ablation energy. In a further embodiment, a method of treating body tissue using ultrasound energy includes identifying a target focal zone to be treated and delivering a plurality of pulses of acoustic ablation energy to locations distributed symmetrically in or proximate a focal plane about the focal center of the target focal zone.

Abstract: Method for adjusting the output of a phased array ultrasonic transducer using surface mapping. The transducer surface is mapped using a sensor, such as a hydrophone, to determine the actual location of each transducer element relative to the expected location of each transducer element. Mapping can be performed by measuring a distance between a hydrophone and each transducer element. At least one of the hydrophone and the transducer are moveable relative to each other to map the transducer surface. A determination is made whether the actual location of a transducer element differs from the expected location. Drive signals of certain transducer elements having actual locations that differ from expected locations are adjusted to control the output of the transducer.

Abstract: An apparatus for delivering acoustic energy to a target site adjacent a body passage includes first and second elongate members, each carrying one or more transducer elements on their distal ends. The first and/or second elongate members include connectors for securing the first and second elongate members together such that the transducer elements together define a transducer array. The first and second elongate members are introduced sequentially into a body passage until the transducer elements are disposed adjacent a target site. Acoustic energy is delivered from the transducer elements to the target site to treat tissue therein. In another embodiment, the apparatus includes a tubular member and an expandable structure carrying a plurality of transducer elements. The structure is expanded between a contracted configuration during delivery and an enlarged configuration when deployed for delivering acoustic energy to a target site adjacent the body passage.

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: A system for treating tissue within a body is configured to deliver a first level of ultrasound energy to a target tissue region for a first duration resulting in the generation of microbubbles in the target tissue region, determine one or more characteristics of the target tissue region in the presence of the microbubbles, and deliver a second level of ultrasound energy to the target tissue region for a second duration, wherein one or both of the second energy level and the second duration are based, at least in part, on the determined one or more characteristics of the target tissue region.

Abstract: A focused ultrasound system includes an ultrasound transducer device forming an opening, and having a plurality of transducer elements positioned at least partially around the opening. A focused ultrasound system includes a structure having a first end for allowing an object to be inserted and a second end for allowing the object to exit, and a plurality of transducer elements coupled to the structure, the transducer elements located relative to each other in a formation that at least partially define an opening, wherein the transducer elements are configured to emit acoustic energy that converges at a focal zone.

Abstract: A method of treating tissue within a body includes directing an ultrasound transducer having a plurality of transducer elements towards target body tissue, and delivering ultrasound energy towards the target tissue from the transducer elements such that an energy intensity at the target tissue is at or above a prescribed treatment level, while an energy intensity at tissue to be protected in the ultrasound energy path of the transducer elements is at or below a prescribed safety level.

Abstract: An apparatus for delivering acoustic energy to a target site adjacent a body passage includes first and second elongate members, each carrying one or more transducer elements on their distal ends. The first and/or second elongate members include connectors for securing the first and second elongate members together such that the transducer elements together define a transducer array. The first and second elongate members are introduced sequentially into a body passage until the transducer elements are disposed adjacent a target site. Acoustic energy is delivered from the transducer elements to the target site to treat tissue therein. In another embodiment, the apparatus includes a tubular member and an expandable structure carrying a plurality of transducer elements. The structure is expanded between a contracted configuration during delivery and an enlarged configuration when deployed for delivering acoustic energy to a target site adjacent the body passage.

Abstract: A focused ultrasound system includes a transducer array, a controller for providing drive signals to the transducer array, and a switch. The transducer array includes a plurality of “n” transducer elements, and the controller includes a plurality of “m” output channels providing sets of drive signals having respective phase shift values, “m” being less than “n.” The switch is coupled to the output channels of the controller and to the transducer elements, and is configured for connecting the output channels to respective transducer elements. The controller may assign the transducer elements to respective output channels based upon a size and/or shape of a desired focal zone within the target region, to steer or otherwise move a location of the focal zone, and/or to compensate for tissue aberrations caused by tissue between the transducer array and the focal zone, geometric tolerances and/or impedance variations of the transducer elements.

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 focusing ultrasonic energy through intervening tissue into a target site within a tissue region includes a transducer array including transducer element, an imager for imaging the tissue region, a processor receiving images from the imager to determine boundaries between different tissue types within the intervening tissue and generate correction factors for the transducer elements to compensate for refraction occurring at the boundaries between the tissue types and/or for variations in speed of sound. A controller is coupled to the processor and the transducer array to receive the correction factors and provide excitation signals to the transducer elements based upon the correction factors. The correction factors may include phase and/or amplitude correction factors, and the phases and/or amplitudes of excitation signals provided to the transducer elements may be adjusted based upon the phase correction factors to focus the ultrasonic energy to treat tissue at the target site.

Abstract: Systems and methods for performing a focused ultrasound procedure monitored using magnetic resonance imaging (MRI) is provided. An MRI system uses a timing sequence for transmitting radio frequency (RF) signals and detecting magnetic resonance (MR) response signals from a patient's body in response to the RF pulse sequences. A piezoelectric transducer is driven with drive signals such that the transducer emits acoustic energy towards a target tissue region within the patient's body. Parameters of the drive signals are changed at times during the timing sequence that minimize interference with the MRI system detecting MR response signals, e.g., during transmission of RF signals by the MRI system.

Abstract: A method of imaging a site of interest in a body using an ultrasound probe comprising a plurality of ultrasound transducer elements comprises obtaining an ultrasound image of a pass zone between the ultrasound probe and the site of interest. The image includes the site of interest and a plurality of tissue regions in a pass zone between the site of interest and the ultrasound probe. Boundaries of a selected tissue region in the pass zone are determined from the image. Focusing delay times are then computed for each ultrasound transducer element based in part on the speed of sound in the selected tissue region other than an average speed of sound in body tissue, and the boundaries of the selected tissue region. Preferably, a speed about the speed of sound in the selected tissue region is used and more preferably the speed of sound in the selected tissue region is used. Refraction may be considered, as well. Ultrasound imaging of the site of interest is then conducted employing the computed delay times.

Abstract: A method of imaging a site of interest in a body using an ultrasound probe comprising a plurality of ultrasound transducer elements comprises obtaining an ultrasound image of a pass zone between the ultrasound probe and the site of interest. The image includes the site of interest and a plurality of tissue regions in a pass zone between the site of interest and the ultrasound probe. Boundaries of a selected tissue region in the pass zone are determined from the image. Focusing delay times are then computed for each ultrasound transducer element based in part on the speed of sound in the selected tissue region other than an average speed of sound in body tissue, and the boundaries of the selected tissue region. Preferably, a speed about the speed of sound in the selected tissue region is used and more preferably the speed of sound in the selected tissue region is used. Refraction may be considered, as well. Ultrasound imaging of the site of interest is then conducted employing the computed delay times.

Abstract: Cells are destroyed within a subcutaneous tissue region using a transducer disposed externally adjacent to a patient's skin. The transducer emits acoustic energy that is focused at a linear focal zone within the tissue region, the acoustic energy having sufficient intensity to rupture cells within the focal zone while minimizing heating. The transducer may include one or more transducer elements having a partial cylindrical shape, a single planar transducer element coupled to an acoustic lens, or a plurality of linear transducer elements disposed adjacent one another in an arcuate or planar configuration. The transducer may include detectors for sensing cavitation occurring with the focal zone, which is correlated to the extent of cell destruction. A frame may be provided for controlling movement of the transducer along the patient's skin, e.g., in response to the extent of cell destruction caused by the 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: Cells are destroyed within a subcutaneous tissue region using a transducer disposed externally adjacent to a patient's skin. The transducer emits acoustic energy that is focused at a linear focal zone within the tissue region, the acoustic energy having sufficient intensity to rupture cells within the focal zone while minimizing heating. The transducer may include one or more transducer elements having a partial cylindrical shape, a single planar transducer element coupled to an acoustic lens, or a plurality of linear transducer elements disposed adjacent one another in an arcuate or planar configuration. The transducer may include detectors for sensing cavitation occurring with the focal zone, which is correlated to the extent of cell destruction. A frame may be provided for controlling movement of the transducer along the patient's skin, e.g., in response to the extent of cell destruction caused by the transducer.

Abstract: A thermal treatment system including a heat applying element for generating thermal doses for ablating a target mass in a patient, a controller for controlling thermal dose properties of the heat applying element, an imager for providing preliminary images of the target mass and thermal images during the treatment, and a planner for automatically constructing a treatment plan, comprising a series of treatment sites that are each represented by a set of thermal dose properties. The planner automatically constructs the treatment plan based on input information including one or more of a volume of the target mass, a distance from a skin surface of the patient to the target mass, a set of default thermal dose prediction properties, a set of user specified thermal dose prediction properties, physical properties of the heat applying elements, and images provided by the imager.

Abstract: A system for performing a therapeutic procedure using focused ultrasound includes a transducer array including a plurality of transducer elements, drive circuitry coupled to the transducer elements, and a controller coupled to the drive circuitry. The controller controls the drive circuitry to alternatively provide sets of the transducer elements with respective drive signals. Each of the sets of transducer elements are alternatively driven with the respective drive signals for a predetermined duration during a sonication, while substantially continuously focusing ultrasonic energy produced by the transducer elements of each set at a desired focal zone. The controller also controls a phase component of the respective drive signals to provide a predetermined size, shape, and/or location of the focal zone, and thereby necrose a target tissue region at the focal zone.

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.