Abstract: Radiation pulses from a high energy therapeutic ultrasound system are used to stimulate tissue motion by radiation pressure. The tissue motion is monitored using a diagnostic ultrasound system.

Abstract: The concentration and/or radii of a contrast agent in a fluid can be estimated by acquiring ultrasound spectral data, performing spectral analysis to generate a linear estimation of the power spectrum, and correlating at least one spectral parameter to a predetermined distribution function for the contrast agent. If the mean radius squared of particles is known, then the concentration of contrast agent particles can be calculated. If the concentration is constant, then relative variations in mean radius squared can be determined.

Abstract: A dual-frequency band ultrasonic apparatus provides a first ultrasound signal to a region at a first frequency band and a second ultrasound signal at a second frequency band for monitoring the region. A processor controls the first and second ultrasound signals such that a predetermined phase relationship is achieved between the first frequency band signal and the second frequency band signal. The apparatus can employ a single transducer operable at both frequency bands or separate transducers for the first and second frequency bands.

Abstract: Signal processors that support transmit or receive beams of two dimensional array antennas generate an appropriate distribution of phase shifts and/or time delays for each of the elements in the antenna array. The signals are processed by row and by column, where corresponding elements are grouped using intermediate frequency tagging, i.e., the elements of a first column are translated to a first intermediate frequency, the elements of a second column are translated to a second intermediate frequency, etc. Signals from elements of like rows are then summed and subjected to a row delay. The delayed signals are then summed and passed through a filter bank, where the summed signal is partitioned in accordance with the plurality of intermediate frequencies into a plurality of column signals. The column signals are subjected to a respective column delays, are translated to a common intermediate or baseband frequency and are summed to establish a received beam signal.

Abstract: Clinical data, ultrasonic radio frequency (RF) backscatter spectral data and histological results of corresponding biopsy sites are stored in a database and are used to train a classifier suitable for real-time tissue classification and imaging. In clinical use, clinical data and ultrasonic RF backscatter data are applied as input variables to the trained classifier which assigns a likelihood of cancer (LOC) score to each pixel location in an ultrasound image. The LOC scores are then categorized by ranges, which can be established by user selected threshold values, to apply different colors or grey scale values distinguishing varying levels of suspicion (LOS) to each pixel position in real-time. This classification and display technique is especially valuable for guiding a person performing a needle biopsy of the prostate.

Abstract: The concentration and/or radii of a contrast agent in a fluid can be estimated by acquiring ultrasound spectral data, performing spectral analysis to generate a linear estimation of the power spectrum, and correlating at least one spectral parameter to a predetermined distribution function for the contrast agent. If the mean radius squared of particles is known, then the concentration of contrast agent particles can be calculated. If the concentration is constant, then relative variations in mean radius squared can be determined.

Abstract: Fluid flow rate and perfusion rate are measured using ultrasound techniques by introducing a contrast agent into a fluid stream and then selectively modifying the contrast agent particles within a target area by the application of a focused pulse of relatively low frequency ultrasonic energy, thus creating a zone of reduced backscatter in the target area. The restoration of the zone of reduced backscatter or the movement of the zone of reduced backscatter is monitored, preferably using high frequency ultrasound, to determine the flow rate or perfusion rate of the fluid. Spectral parameters of ultrasound return signals are evaluated to determine an estimate of contrast agent concentration and/or mean particle size.

Abstract: A spherical cap transducer is provided with at least one electrode formed as segments. The segments are selectively driven to provide asymmetrical ovoid effective radiation patterns for treatment of tissue with ultrasonic radiation.

Abstract: A phased array antenna system compensates for the effects of antenna flexure, vibration and movement, and thereby negates these effects by introducing an appropriate phase or time delay into the signals being radiated from and received by the discrete antenna elements comprising the phased array antenna. This compensation eliminates the need for massive rigid back structures to maintain antenna rigidity, which thereby simplifies antenna design.

Abstract: An ultrasound system that enables determination of layer thicknesses and contours of a multi-layer organic body includes a transmitter/receiver for obtaining a radio frequency signal from echoes over a plurality of points on the organic surface. Each radio frequency signal is then deconvolved to remove apparatus generated noise and filtered to create an analytic signal that exhibits a magnitude related to an instantaneous rate of arrival of total echo energy received by the transmitter/receiver. Analytic signals from adjacent parallel scans are then cross-correlated and magnitude detected to determine energy peaks to enable accurate determination of echo producing surfaces of each layer of the multi-layer organic body across the plurality of interrogation points. In the application of the invention to Corneal Epithelium Mapping, a pupil monitoring system is included that disables the measurement system if the pupil's gaze wanders so as to cause a diversion of the optical axis.

Abstract: A method and an apparatus for applying a therapeutic substance to body tissue are provided in which ultrasonic radiation is used. The method allows the application of medication to be tailored to the needs of an individual patient. In particular, the timing, duration, intensity, and concentration of the application of medication can be adjusted according to individual requirements. Side effects of tissue adjacent to tissue in need oThe invention described herein was made in the course of work under a grant from the National Institute of Health.

Abstract: A system is described for obtaining in real-time cross-sectional and 3-dimensional images of a body under study using ultrasonic energy. A piezoelectric transducer is positioned to emit ultrasonic energy and receive echo pulses. The transducer is electronically swept or physically rotated to produce a series of sectored scan planes which are separated by a known angular distance. The echo pulses are processed to produce an ultrasonic image in pseudo 3-dimensional display. By using data from one scan plane, processed as a B-scan image, cross-sectional data can be obtained. Such is combined in a display with an overlay to visually portray the object and positioning information or comparative data. The system is combined with a computer for data analysis and a therapeutic transducer for treatment.

Abstract: A method for self-referencing holography makes use of multiple object illuminations with different and non-uniform intensity of radiation to produce multiple holograms from the scattered radiation. Analysis of the multiple holograms provides an unambiguous image of the object.

Abstract: Methods for enhancement of data obtained from scanning objects such as body tissue with ultrasonic wideband pulses to detect characteristics of the tissue and to identify the tissue. The methods include performing spectral analysis on selected time portions of signals obtained from ultrasonic scanning to derive spectral data which is representative of the received signal characteristics for spatial samples of a particular region of interest in the body. The characteristic values are selected to correlate with significant characteristics of the material. A display of the selected body region is generated, with the display characteristic for each of the spatial samples being selected in accordance with the derived spectral characteristic values. Examples of the spectral characteristic values include spectral amplitude, spectral slope, and spectral amplitude uncertainty.

Abstract: An optical system makes use of solar illumination as a light source to achieve covert operation.

Abstract: Methods for improving the availability of information derived from signals received from an object irradiated with coherent pulses of any form of radiation that exhibits a wave nature are disclosed. A method for reducing speckle derives separate component noncoherent signals from the received signals, and combines these separate noncoherent signals to form improved composite noncoherent signals. Weighting and processing of component signals can be applied as a function of time, frequency, and signal amplitude to optimize speckle reduction in all or a critical part of the signal by compensating for the range and frequency dependence of attenuation and the frequency dependence of scattering phenomena. In a method for enhancing resolution, separate component coherent signals are derived from the received signals, weighted and processed, and combined to form improved composite coherent signals; then noncoherent signals are derived from the improved composite coherent signals.

Abstract: An ultrasonic transducer assembly is provided with transducers for both therapeutic and diagnostic ultrasonic radiation. A moveable seal permits adjustment and alignment of the two transducer units in a fluid medium. In addition, there is provided a light beam directed along the axis of the ultrasonic radiation. The transducer assembly is particularly useful for ophthalmic therapy.

Abstract: An ultrasonic wave transducer is formed from a body of piezoelectric material having nonuniform thickness. Each location on the transducer is resonant at a different frequency according to the thickness at that point. By changing the frequency of the applied excitation signal, the origin and direction of the radiation can be altered.

Abstract: Methods for improving the availability of information derived from signals received from an object irradiated with coherent pulses of any form of radiation that exhibits a wave nature are disclosed. A method for reducing speckle derives separate component noncoherent signals from the received signals, and combines these separate noncoherent signals to form improved composite noncoherent signals. Weighting and processing of component signals can be applied as a function of time, frequency, and signal amplitude to optimize speckle reduction in all or a critical part of the signal by compensating for the range and frequency dependence of attenuation and the frequency dependence of scattering phenomena. In a method for enhancing resolution, separate component coherent signals are derived from the received signals, weighted and processed, and combined to form improved composite coherent signals; then noncoherent signals are derived from the improved composite coherent signals.