NIBIB - Resource on Medical Ultrasonic Transducer Technology

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Ultrasonic Image of an Excised Eye. This image of the anterior segments of the eye at 50 MHz was obtained by a prototype ultrasonic backscatter microscope developed at USC.

Resource on Medical Ultrasonic Transducer Technology

Contact Information
Grant Number
Research Emphasis
Current Research
Resource Capabilities
References

Contact Information

University of Southern California
Department of Biomedical Engineering

Ultrasonic Transducer Research Center

136 Denney Research Building
Los Angeles, CA 90089-1451

http://bme.usc.edu/UTRC/

Principal Investigator/Contact

K. Kirk Shung, Ph.D.
Phone: 213-821-2653

Fax: 213-740-0343
kkshung@usc.edu

Contact
Jon Cannata, Ph.D.
Phone: 213-821-2649
Fax: 213-740-0343
cannata@usc.edu

Grant Number

Grant No. EB002182

Research Emphasis

The focus of this resource is to develop very high frequency (above 20 MHz) ultrasonic transducers/arrays for applications in medicine and biology that include ophthalmology, dermatology, vascular surgery, and small animal imaging. The research is pursued simultaneously in three directions: novel piezoelectric materials, very high frequency single element transducers and linear arrays, and finite element modeling and material property measurements.

Current Research

Single crystal ferroelectric relaxor materials of varying composition including PYN-PT, fine-grain PZT, ultra-fine spatial scale 1-3 and 2-2 composites, high dielectric PT, lithium niobate, and novel matching layer and backing materials are studied for their suitability as very high frequency transducer materials. Single element transducers made from these materials in the frequency range from 30 to 200 MHz have been developed and used for patient scanning by internal as well as external investigators. A 6-element annular array, a 48-element 30 MHz composite linear array and a 64-element 35 MHz PZT array have been designed and built. A flexible digital FPGA based 16 channel beamformer capable of handling frequencies up to 50 MHz has been developed and has been interfaced to the arrays. Images have been acquired on wire phantoms and excised eye specimens.

An ultrasonic backscatter microscope (UBM) developed under the support of this grant is also available for experimental studies. Finite element modeling tools are being used to simulate array performance, to examine the effect of acoustic crosstalk, and to investigate different transducer and piezocomposite design strategies. Elastic and acoustic properties of transducer materials, including novel piezoceramics and materials for lenses, matching layers, backing blocks, and kerf fillers have been measured.

Resource Capabilities

Hardware

Thermocarbon Tcar 846-1 dicing saw
Speedline Technologies PDS 2010 Parylene coating system
Nano-Master NSC-3000 sputtering system
Modular Process Technology Corp RTP-600S rapid thermal annealing furnace
Logitech PM5 lapping machine
Prazi SD 400 lathe
Carver hot press
ThermoLyne 46100 high temperature oven
Linberg/Blue low temperature furnace
Fritsch Pulverisette 5 milling machine
LeCroy LC534 1 GHz digital oscilloscope
Tektronix TDS 5052 5 GHz digital oscilloscope
125 MHz HP hydrophones
40 MHz Precision Acoustics hydrophone
High-precision test tanks
Optison real-time schlieren system
100 MHz and 500 MHz HP electrical impedance analyzers

Software

KLM transducer modeling packages
PZFlex time domain finite element analysis software
FIELD II ultrasonic beam simulation tool

Service Personnel and Services

Two full-time engineers and one full-time technician are available for consultation and to assist in device design and fabrication.
Resource facilities are available for transducer design and fabrication, and training.

References

Wang H, Ritter T, Cao W, Shung KK. High frequency properties of passive materials for ultrasonic transducers. IEEE Trans. Ultrasonics, Ferroelectrics, and Frequency Control 2001;48:78-84.
Ritter TR, Shrout TR, Tutwiler R, Shung KK. A 30 MHz piezo-composite ultrasound array for medical imaging applications. IEEE Trans. Ultrasonics, Ferroelectrics, and Frequency Control 2002;48:213-230.
Snook K, Zhao J, Shung KK, et al. Design, fabrication and testing of high frequency single element transducers incorporating different materials. IEEE Trans. Ultrasonics, Ferroelectrics, and Frequency Control 2002;48:169-176.
Cannata J, Ritter T, Silverman R, Shung K. Design of Efficient, Broadband Single Element (20 - 80 MHz) Ultrasonic Transducers for Medical Imaging Applications. IEEE Trans Ultras. Ferroelect. Freq. Cont. 2003;50:1548-1557.
Robert M, Molingou G, Snook K, Cannata J, Shung KK. Fabrication of focused P(VDF-TrFE) copolymer 40 -50 MHz ultrasonic transducers on curved surfaces. Journal of Applied Physics 2004;96:252-256.
Silverman RH, Chabi A, Rondeau MJ, Shung KK, Cannata J, Lincoff H, Coleman DJ. High resolution ultrasonic imaging of the posterior segment. Ophthalmology 2004;111:1344-1351.

Last reviewed on: 12/21/2006

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