Abstract: A system and method utilizing thermoacoustic imaging to estimating tissue temperature within a region of interest that includes an object of interest and a reference which are separated by at least one boundary located at least at two boundary locations. The system and method use a thermoacoustic imaging system that includes an adjustable radio frequency (RF) applicator configured to emit RF energy pulses into the tissue region of interest and heat tissue therein and an acoustic receiver configured to receive bipolar acoustic signals generated in response to heating of tissue in the region of interest; and one or more processors that are able to: process received bipolar acoustic generated in the region of interest in response to the RF energy pulses to determine a peak-to-peak amplitude thereof; and calculate a temperature at the at least two boundary locations using the peak-to-peak amplitudes of the bipolar acoustic signals and a distance between the boundary locations.

Abstract: A thermoacoustic imaging method comprises administering a thermoacoustic imaging contrast agent to a subject, the thermoacoustic imaging contrast agent having a viscosity higher than blood and substantially similar to a viscosity of a known computed tomography (CT) or magnetic resonance imaging (MRI) contrast agent; and imaging the subject with a thermoacoustic imaging system. The thermoacoustic imaging contrast agent may comprise an ionic solution and thickening agent mixture, with an optional heating agent. The ionic salt makes 0.5% to 5.0% of the ionic solution by weight and the remainder of the ionic solution is water. The thickening agent makes 3% to 50% of the mixture by weight.

Abstract: An ultrasound transducer with at least one piezoelectric element configured to convert received acoustic signals into an electric potential, a shield connectable to ground and overlying the at least one piezoelectric element through which the acoustic signals pass, before being received by the at least one piezoelectric element, the shield having acoustic conductivity and electrical attenuation characteristics that enable the acoustic signals to propagate therethrough while reducing a 100 volt per centimeter electric field to below a threshold level so that the piezoelectric element is exposed to a threshold electrical potential at least less than or equal to 10 ?V, and a housing accommodating the at least one piezoelectric element and shield.

Abstract: A system comprises an ultrasound imaging system comprising at least one ultrasound transducer array, a thermoacoustic imaging system comprising at least one thermoacoustic transducer array mechanically connected to the at least one ultrasound transducer array such that a centerline of the at least one thermoacoustic transducer array is at a known angle with respect to a centerline of the at least one ultrasound transducer array, the at least one ultrasound transducer array moveable to orient the at least one thermoacoustic transducer array in at least one imaging position based on the known angle; and a processing unit configured to obtain thermoacoustic data of a region of interest at the at least one imaging position using the at least one thermoacoustic transducer array.

Abstract: A method of obtaining thermoacoustic data comprises obtaining ultrasound data of a region of interest using at least one ultrasound transducer array, the at least one ultrasound transducer array mechanically connected to at least one thermoacoustic transducer array such that a centerline of the at least one thermoacoustic transducer array is at a known angle with respect to a centerline of the at least one ultrasound transducer array, adjusting a position of the at least one ultrasound transducer array to orient the at least one thermoacoustic transducer array in at least one imaging position based on the known angle, and obtaining thermoacoustic data of the region of interest at the at least one imaging position using the at least one thermoacoustic transducer array.

Abstract: A system and method for determining fractional fat content of tissue comprises registering thermoacoustic image coordinates to an acquired ultrasound image, the acquired ultrasound image at least comprising target tissue within a region of interest; defining a thermoacoustic voxel grid coincident with the region of interest; obtaining thermoacoustic image measurement values from tissue within the region of interest corresponding to the voxels within the defined thermoecoustic voxel grid to yield a thermoacoustic measurement matrix; normalizing the thermoacoustic image measurement values within the thermoacoustic measurement matrix; calculating a fractional fat content map for the target tissue within the region of interest based on the normalized thermoacoustic image measurement values within the thermoacoustic measurement matrix and a reference thermoacoustic measurement value; and correcting the fractional fat content map based on tissue speed-of-sound data to yield a final fractional fat content map for th

Abstract: A system and method for determining fractional fat content of tissue comprises registering thermoacoustic image coordinates to an acquired ultrasound image, the acquired ultrasound image at least comprising target tissue within a region of interest; defining a thermoacoustic voxel grid coincident with the region of interest; obtaining thermoacoustic image measurement values from tissue within the region of interest corresponding to the voxels within the defined thermoecoustic voxel grid to yield a thermoacoustic measurement matrix; normalizing the thermoacoustic image measurement values within the thermoacoustic measurement matrix; calculating a fractional fat content map for the target tissue within the region of interest based on the normalized thermoacoustic image measurement values within the thermoacoustic measurement matrix and a reference thermoacoustic measurement value; and correcting the fractional fat content map based on tissue speed-of-sound data to yield a final fractional fat content map for th

Abstract: Combined transducer arrays for imaging features of tissue include a transducer array configured for transmit-receive ultrasound imaging, and a transducer array configured for receive-only thermoacoustic imaging. The transmit-receive transducer array includes a plurality of transmit-receive array elements, and the receive-only transducer array includes a plurality of receive-only array elements. The receive-only array elements are registered with and surround the transmit-receive array elements. The receive-only transducer array and transmit-receive transducer array may be housed in an ultrasound probe. The combined transducer arrays may be used in composite imaging of tissue, based on the registration of the transmit-receive array elements and the receive-only array elements.

Abstract: A thermoacoustic imaging system is provided for use in combination with an ultrasound imaging system for imaging features of tissue, the ultrasound imaging system including an ultrasound imaging probe including a transmit-receive transducer array with a plurality of transmit-receive array elements. The thermoacoustic imaging system includes a receive-only transducer array with a plurality of receive-only array elements, registered with the plurality of transmit-receive array elements. The transmit-receive transducer array is housed in an ultrasound imaging probe, and the receive-only transducer array is housed in a thermoacoustic imaging probe. The thermoacoustic imaging probe is mechanically joined to the ultrasound imaging probe, e.g., as a sleeve fitted to the ultrasound imaging probe.

Abstract: A method for correcting fat-induced aberrations in ultrasound imaging comprises segmenting a thermoacoustic absorption image of a region of interest into at least one fat region and at least one non-fat region, creating a speed of sound map by assigning a speed of sound to each region based on tissue type of the region, correcting aberrations in the segmented thermoacoustic absorption image using the assigned speeds of sound thereby generating a corrected thermoacoustic image, and correcting an ultrasound image of the region of interest using the corrected thermoacoustic image and the speed of sound map.

Abstract: A system for estimating fractional fat content of an object of interest. An energy emitter is used to direct an energy signal toward the region of interest, wherein the region of interest has an object of interest, a reference with known properties, and a boundary area with one or more boundary locations between the object of interest and the reference. Next, a plurality of thermoacoustic or ultrasonic transducers is used to receive a plurality of thermoacoustic bipolar signals from the one or more boundary locations, wherein the thermoacoustic bipolar signals are induced by the energy signal. A machine configured to accept data from the energy emitter and the plurality of thermoacoustic or ultrasonic transducers and calculate a fat concentration that is a function of a difference between two peaks of the thermoacoustic bipolar signal at each respective boundary location and a distance or distances between each respective boundary location.

Abstract: A method and system for estimating fractional fat content of an object of interest. An energy emitter is used to direct an energy signal with an energy signal electric field strength toward the region of interest, wherein the region of interest has an object of interest, a reference, and a boundary between the object of interest and the reference. Next, a thermoacoustic or ultrasonic transducer is used to receive a thermoacoustic bipolar signal from the boundary, wherein the thermoacoustic bipolar signal is induced by the energy signal. Finally, a machine is used to accept data from the energy emitter and thermoacoustic or ultrasonic transducer, correlate the thermoacoustic bipolar signal to an electric field strength of the reference at the boundary to generate a corrected thermoacoustic bipolar signal at the boundary, and calculate a fat concentration of the object of interest as a function of the corrected thermoacoustic bipolar signal at the boundary.

Abstract: A method and system for estimating fractional fat content of an object of interest. An energy emitter is used to direct an energy signal toward the region of interest, wherein the region of interest has an object of interest, a reference, and a boundary area with one or more boundary locations between the object of interest and the reference. Next, a plurality of thermoacoustic or ultrasonic transducers is used to receive a plurality of thermoacoustic bipolar signals from the one or more boundary locations, wherein the thermoacoustic bipolar signals are induced by the energy signal. A machine configured to accept data from the energy emitter and the plurality of thermoacoustic or ultrasonic transducers and calculate a fat concentration that is a function of the thermoacoustic bipolar signal at each respective boundary location and the distance or distances between locations.

Abstract: A method for estimating fractional fat content of an object of interest is described. The method comprises obtaining thermoacoustic data of a region of interest containing an object of interest and a reference, and estimating fractional fat content of the object of interest using the thermoacoustic data and at least one parameter of the reference.

Abstract: A thermoacoustic imaging system is provided for use in combination with an ultrasound imaging system for imaging features of tissue, the ultrasound imaging system including an ultrasound imaging probe including a transmit-receive transducer array with a plurality of transmit-receive array elements. The thermoacoustic imaging system includes a receive-only transducer array with a plurality of receive-only array elements, registered with the plurality of transmit-receive array elements. The transmit-receive transducer array is housed in an ultrasound imaging probe, and the receive-only transducer array is housed in a thermoacoustic imaging probe. The thermoacoustic imaging probe is mechanically joined to the ultrasound imaging probe, e.g., as a sleeve fitted to the ultrasound imaging probe.

Abstract: A method for correcting fat-induced aberrations in ultrasound imaging comprises segmenting a thermoacoustic absorption image of a region of interest into at least one fat region and at least one non-fat region, creating a speed of sound map by assigning a speed of sound to each region based on tissue type of the region, correcting aberrations in the segmented thermoacoustic absorption image using the assigned speeds of sound thereby generating a corrected thermoacoustic image, and correcting an ultrasound image of the region of interest using the corrected thermoacoustic image and the speed of sound map.

Abstract: Methods and systems to analyze soft tissue or vasculature in a subject, form images with enhanced soft tissue contrast, determine blood flow parameters in soft tissue or vasculature, and to aid in the diagnosis of disease using thermoacoustic methods. Pulsed electromagnetic energy is administered to tissue to excite a thermoacoustic signal in the soft tissue or vasculature. An acoustic receiver or receiver array is coupled to a subject to detect and record the thermoacoustic signals produced. Thermoacoustic data are acquired after administration of a physiologically-tolerable tracer or contrast agent. The acquired data may be analyzed to produce images of the soft tissue and vasculature (angiogram), to determine blood flow parameters, and/or to diagnose disease in a subject.

Abstract: The invention features a system for imaging tissue including (i) a source of electromagnetic radiation; (ii) an encasement h a plurality of acoustic transducers (e.g., at least 128); (iii) a support structure having a portion for holding a tissue; and (iv) a chamber between the encasement and support structure for housing an acoustic coupling medium. In the system, electromagnetic radiation from the source is sufficient to induce a thermoacoustic response in the tissue positioned in the support structure, and the plurality of acoustic transducers are positioned to receive ultrasound from the thermoacoustic response of the tissue. The invention also features methods of imaging a tissue using the systems.

Abstract: A method for evaluating the spatial resolution of a volumetric medical imaging system comprises imaging an image phantom including a sphere surrounded by a uniform medium. The image phantom is imaged and the resulting volumetric data set is used to generate an edge response function in three dimensions. Differentiating the edge response function produces a plane spread function. The method simultaneously measures the spatial resolution in all directions, providing a bulk measurement resolution. Alternatively, the edge response function may be assembled in a manner so as to independently measure the axial and trans-axial resolution of the volumetric imaging system.

Abstract: A method for evaluating the spatial resolution of a volumetric medical imaging system comprises imaging an image phantom including a sphere surrounded by a uniform medium. The image phantom is imaged and the resulting volumetric data set is used to generate an edge response function in three dimensions. Differentiating the edge response function produces a plane spread function. The method simultaneously measures the spatial resolution in all directions, providing a bulk measurement resolution. Alternatively, the edge response function may be assembled in a manner so as to independently measure the axial and trans-axial resolution of the volumetric imaging system.