SBIR-STTR Award

The objective of the proposed work is to develop technology which results in probes ultrasound with performance at or near the level of probes designed for diagnostic imaging but with the increased efficiency and power handling capability which is necessary for some applications, such as acoustic radiation force impulse (ARFI) imaging and combined imaging / HIFU therapy. Probes with high bandwidth, sensitivity, and efficiency will enable ARFI to operate in real time and will improve the image guidance for HIFU applications. Development of multilayer multirow array technology will ultimately lead to better elevation focusing capability in both diagnostic and therapy modes, and open the possibility of electrically matched array elements without the need for a transformer. Thus resolution can be improved for imaging, and therapy devices can be easily focused at multiple depths for treatment of both near-surface and deep-lying ailments with a single device. The specific aims of Phase I are as follows. Experimentally validate through thermocouple measurements the relative power dissipation of probe components, such as the backing, piezoceramic, and lens materials. Compare the power dissipation and efficiency of probes designed for diagnostic imaging with that of probes designed for increased power handling capability using low loss piezoceramic and modified acoustic designs. Evaluate the properties of low loss piezoceramic multilayers by fabricating prototypes with an established process. Establish the feasibility of applying stacked multilayer technology to multirow arrays by extending established processes to individual multilayers with small elevation dimensions and to selectively plated full-elevation plates. In cooperation with researchers active in the field, determine probe configurations and performance specifications for high resolution high power arrays which can benefit from the technology developed in this program.

Thesaurus Terms:
biomedical equipment development, image processing, ultrasound imaging /scanning ceramic, diagnosis quality /standard, image enhancement, measurement, optics, ultrasonography bioengineering /biomedical engineering, bioimaging /biomedical imaging

The objective of this program is to apply proprietary bonded piezoelectric composite multilayer technology to a variety of ultrasound arrays for both imaging and therapy, which are currently limited in their ability to deliver acoustic power to the human body. Focus areas include: 1) conventional imaging arrays which are limited by probe heating, particularly in Doppler and Harmonics mode; 2) arrays to enable acoustic radiation force impulse (ARFI) imaging to operate in real-time (e.g. 2 to 10 frames / sec); and 3) arrays for improved high intensity focused ultrasound (HIFU) thermal therapy and dual-use ultrasound guidance of HIFU therapy. Because multilayers can result in matched electrical impedance between the probe and electronics without the need for transformers, it is particularly useful for clinical applications where the probe size is strictly limited, e.g. intracavity, laproscopic, and catheter-based procedures. Phase I has demonstrated the potential of PZT multilayers to operate under high power while maintaining the bandwidth and sensitivity of conventional probes designed exclusively for imaging. The feasibility of applying multilayer technology to matrix arrays (matrix multilayers) opens additional opportunities for devices with adjustable elevation aperture, focus, or steering, to effectively image and treat volumes without mechanical movement of the device, i.e. fully electronic arrays. In Phase II prototype devices will be built in each of the target areas, first in the form of multilayer 1-D arrays operating from 1 to 4 MHz. Process refinements will result in 1-D multilayers operating at higher frequencies, and matrix multilayers applied to 1.25-D to 1.75-D arrays. The development of transducer specifications and the characterization of prototypes will be carried out at Tetrad with input from researchers at Duke and Harvard Universities. A mix of commercial products and research tools will be developed under this program, and the technology should enable more rapid development and ultimately commercialization of new imaging and therapy modes which will depend on the availability of high power arrays also capable of diagnostic quality imaging.

Thesaurus Terms:
biomedical equipment development, clinical biomedical equipment, diagnosis design /evaluation, image processing, ultrasonography diagnosis quality /standard, heart imaging /visualization /scanning, image guided surgery /therapy, prostate bioengineering /biomedical engineering, scanning electron microscopy