There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

The embodiments contemplate methods and devices for communicating an acoustic emission via an array of transducers and wirelessly communicating data via a transceiver, where the transceiver may be in communication with the array of transducers. Embodiments also contemplate providing power for the acoustic emission via a power source and providing information regarding a temperature sensor to the transceiver. The wirelessly communicated data may include the information regarding the temperature sensor. Embodiments also contemplate processing the wirelessly communicated data at a relatively remote location with respect to both the power source and the temperature sensor.

Transducer array imaging system

Photoacoustic imaging is a promising method for visualizing biological tissues with optical absorbers. This article provides an overview of the rapidly developing field of photoacoustic imaging. Photoacoustics, the physical basis of photoacoustic imaging, is analyzed briefly. The merits of photoacoustic technology, compared with optical imaging and ultrasonic imaging, are described. Various imaging techniques are also discussed, including scanning tomography, computed tomography and original detection of photoacoustic imaging. Finally, some biomedical applications of photoacoustic imaging are summarized.

Photoacoustic imaging in biomedicine

This paper provides a detailed overview of developments in transducer materials technology relating to their current and future applications in micro-scale devices. Recent advances in piezoelectric, magnetostrictive and shape-memory alloy systems are discussed and emerging transducer materials such as magnetic nanoparticles, expandable micro-spheres and conductive polymers are introduced. Materials properties, transducer mechanisms and end applications are described and the potential for integration of the materials with ancillary systems components is viewed as an essential consideration. The review concludes with a short discussion of structural polymers that are extending the range of micro-fabrication techniques available to designers and production engineers beyond the limitations of silicon fabrication technology.

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New materials for micro-scale sensors and actuators An engineering review

An interchangeable transducer for use with an ultrasound medical system having a keyless adaptor and capable of operating in a wet environment. The interchangeable transducer has an adaptor for engaging a medical system, an ultrasound transducer and additional electronics to provide a self-contained insert for easy replacement and usage in a variety of medical applications. A slip ring spacer is also disclosed, the slip ring spacer for use with a pancake slip ring having a base and flange configuration to form one or more channels around each contact ring of the pancake slip ring. The channels provide fluid isolation around each connector to help reduce electronic cross talk and contact corrosion between the connector pads of the slip ring while the slip ring is immersed in a wet environment.

Slip ring spacer and method for its use

A system for acquiring an ultrasound signal comprises a signal processing unit adapted for acquiring a received ultrasound signal from an ultrasound transducer having a plurality of elements. The system is adapted to receive ultrasound signals having a frequency of at least 20 megahertz (MHz) with a transducer having a field of view of at least 5.0 millimeters (mm) at a frame rate of at least 20 frames per second (fps). The signal processing can further produce an ultrasound image from the acquired ultrasound signal. The transducer can be a linear array transducer, a phased array transducer, a two-dimensional (2-D) array transducer, or a curved array transducer.

High frequency array ultrasound system

Provided herein are compositions comprising a microbubble contrast agent, wherein at least 20% by volume of the microbubbles in the contrast agent has a size of less than 1 micron, wherein the contrast agent produces non-linear scattering when contacted by ultrasound at a frequency above 20 MHz. Provided herein are compositions comprising a microbubble contrast agent, wherein at least 10% by volume of the microbubbles in the contrast agent has a size of less than 500 nanometers, wherein the contrast agent produces non-linear scattering when contacted by ultrasound at a frequency above 20 MHz. Provided herein are compositions comprising a microbubble contrast agent, wherein at least 5% by volume of the microbubbles in the contrast agent has a size of less than 200 nanometers, wherein the contrast agent produces non-linear scattering when contacted by ultrasound at a frequency above 20 MHz. The disclosed contrast agents can be targeted contrast agents. Further provided are methods of using the compositions disclosed herein. Specifically provided are methods for producing an ultrasound image comprising: administering contrast agent to a laboratory animal; generating ultrasound at a frequency of at least 20 MHz; transmitting ultrasound at a frequency of at least 20 MHz into the subject; receiving non-linear ultrasound from the contrast agent in the subject; processing the received ultrasound to provide an image.

High frequency ultrasound imaging using contrast agents

A sol gel composite process has been used to produce lead zirconate titanate coatings in the thickness range of 3 to 100 /spl mu/m on aluminum substrates. The complex permittivity (/spl epsi//sub 33//sup S/), elastic stiffness (c/sub 33//sup D/), and the piezoelectric constant (h/sub 33/) of the coating and the complex elastic stiffness (c/sub 33//sup D/) of the substrate have been determined using impedance measurements and a commercially available software program [Piezoelectric Resonance Analysis Program PRAP 2.0, TASI Technical Software, Kingston, Ontario, Canada]. The complex components of the material parameters account for the losses within the film and the substrate. Sol gel composite films on aluminum have a dielectric constant of 220 with an imaginary component of 1% and an electromechanical coupling coefficient of up to 0.24 with an imaginary component of 3%. These films are applied to the fabrication of a high frequency transducers suitable for ultrasound biomicroscopy (UBM). By combining the sol gel composite material with existing transducer fabrication techniques, single-element focusing transducers have been produced that operate in the frequency range of 70 to 160 MHz. Devices have -6-dB bandwidths up to 52% and minimum insertion losses ranging from -47 to -58 dB. Real-time images of phantom materials and ex vivo biological samples are shown.

Single element high frequency (<50 MHz) PZT sol gel composite ultrasound transducers

Piezoelectric ceramics have been patterned by means of laser micromachining to create ultrasonic arrays resonating in the frequency range of 35-45 MHz. The Lumonics PM-844 excimer laser with a KrF gas mixture (248 nm) has been used to micromachine trenches with a width to depth aspect ratio of up to 1:5. By using a projection etch approach, the large aperture of the excimer laser is used to simultaneously ablate the features of a complex geometrical pattern. Pre-poled ceramic structures >20 /spl mu/m wide and >35 /spl mu/m thick have been cut and validated with SEM images. The dielectric, piezoelectric and acoustic properties have been evaluated using an impedance analyser and pulse-echo techniques.

Laser micromachined high frequency ultrasonic arrays

A system for producing an ultrasound image comprises a scan head (106) having a transducer (124) capable of generating ultrasound energy at a frequency of at least 20 megahertz (MHz), and a processor (134) for receiving ultrasound energy and for generating an ultrasound image (116) at a frame rate of at least 15 frames per second (fps).

Stuart Foster

Papers

High frequency array ultrasound system

High frequency ultrasound imaging using contrast agents

Single element high frequency (<50 MHz) PZT sol gel composite ultrasound transducers

Laser micromachined high frequency ultrasonic arrays

High frequency, high frame-rate ultrasound imaging system