The United States of America As Represented by the Department of Health

National Institutes of Health, a Component of the US Dept. of Health & Human Services

St Jude Medical, Atrial Fibrillation Division, Inc

University of Cincinnati

Gerald R Harris

Aime S DeReggi

John W Sliwa, Jr

Ronald A Robinson

Rupak K Banerjee

Matthew R Myers

Aime' S DeReggi

Subha Maruvada

Prasanna Hariharan

A system for optically characterizing an acoustic beam generally includes an immersant, which is an immersion medium seeded with a plurality of seed particles that respond to illumination with fluorescence indicative of at least one parameter of the immersant such as flow or temperature. Optical transmitters illuminate the immersant slicewise, and optical receptors receive the fluorescence in order to generate a three-dimensional map of the parameter over time. A processor back-calculates one or more characteristics of an acoustic beam that results in the map. The processor initially generates a behavior model of an acoustic beam propagating in the immersant by utilizing initial guesses for the characteristics. The initial guess model is compared to the map, and an optimization routine is used to refine the initial guesses. The process repeats iteratively with refined guesses until the difference between the model and the map is minimized.

Optical techniques and system for 3-D characterization of ultrasound beams

A hydrophone device with one or more very small active spots located on a large continuous ferroelectric sheet, such as PVDF, overcomes many of the problems in prior art constructions associated with the high dielectric constant of various media in which the device is used. Additional improvements include increased signal to noise ratio and a sensitivity independent of the medium properties. The hydrophone device includes a piezoelectrically active sheet stretched and clamped on over the top of a hoop ring. A backing is attached to the back of the hoop ring. A low-dielectric material fills the space between the backing and the sheet. This material eliminates the capacitive loading effect which would otherwise be presented by the medium being probed.

Transducer hydrophone with filled reservoir

An acoustically transparent hydrophone probe consisting of a rigid hoop structure in which is secured an assembly of very thin piezoelectric polymer sheet material, such as polyvinylidene fluoride, with one or more very small central sensitive portions. In its simplest form it consists of a single sheet with a small central poled piezoelectric area and with very thin metallic electrodes deposited on the sheet on opposite sides of the piezoelectric area and having fine conductive leads extending from the electrodes and adapted to be connected to a suitable amplifier or transmission line. The sheet is of biaxially stretched material, and is held taut in the hoop structure. Other embodiments may employ multiple sheets. With two sheets, the outermost surfaces are metallized and are at common ground potential, and the inner surfaces have superimposed deposited metallic electrodes with poled piezoelectric areas adjacent thereto. The electrodes have superimposed deposited metallic leads which have a common electrical connection to a transmission line or to an amplifier. With four sheets, the two innermost sheets form a bilaminate subassembly similar to the 2-sheet embodiment. The outer sheets have metallized outer surfaces which are grounded. Between said outer sheets and the bilaminate subassembly, guard rings coaxial with the piezoelectric active areas are provided. The guard rings can be driven electrically in a manner to eliminate the effects of the capacitance of the electrical leads.

Acoustically transparent hydrophone probe

Growing community of inventors

Rockville, MD, United States of America

Gerald R Harris