RESEARCH Science Engineering

HEALTH CARE
Ultrasonic microprobe may rapidly detect, identify cancer

James E. Kloeppel, Physical Sciences Editor
(217) 244-1073; kloeppel@uiuc.edu

5/1/2001

CHAMPAIGN, Ill. — Surgical biopsies can be painful, and waiting for lab results unnerving. New ultrasonic sensor technology being developed at the University of Illinois may permit the rapid and accurate detection and diagnosis of cancer, without the need of a scalpel.

"By inserting a miniature probe into a tumor and using pulses of sound waves to image the surrounding tissue, our system could facilitate the early diagnosis of cancer," said William O’Brien Jr., a UI professor of electrical and computer engineering and the director of the Bioacoustics Research Laboratory at the university’s Beckman Institute for Advanced Science and Technology.

The probe functions in the same manner as the transducers used in conventional diagnostic ultrasound imaging. Operating at a frequency of 300 MHz, however, the ultrasound image resolution would be comparable to what a pathologist sees when examining tissue under a microscope.

"When evaluating a potentially cancerous tumor, a pathologist will look for certain features in cell structure and growth pattern," said James F. Zachary, a UI professor and interim department head of veterinary pathobiology. "By examining the size and shape of the cells, and how they interact with surrounding tissue, a determination can be made whether the tumor is malignant or benign."

The ultrasonic microprobe would allow a pathologist to accomplish the same goal as a surgical biopsy but through a rapid and minimally invasive procedure, Zachary said. "By inserting the probe into a tumor and displaying the image on a monitor, we could identify and classify the tumor in real time. We could also send the image over the Internet to specific specialists for help in identification."

To get to their target frequency of 300 MHz, the researchers are fabricating transducers from a particular type of high-strain piezoelectric material. "This material has the potential for being extremely efficient, but it’s also very fragile," O’Brien said. "The thinner the crystal, the higher the frequency response – and that has presented certain mechanical difficulties."

Currently, the researchers have three major parts of the project coming together. They have created miniature probes that work at up to 70 MHz, they have devised functional image-formation techniques, and they are developing a database of ultrasound images of both tumors and healthy tissue.

"We still need to push the transducer frequency response up to 300 MHz, and we need to make the probes much smaller," O’Brien said. "Ultimately, we want to mount the transducer on the end of an acupuncture needle. That way, when the probe is inserted, the patient will feel no pain."

In addition to O’Brien and Zachary, collaborators on the project include materials science and engineering professor David Payne, electrical and computer engineering professor Doug Jones, postdoctoral research associates Karen Topp, Pengi Han and Michael Oelze, and graduate student Mark Haun.

A paper describing the microprobe’s image characteristics has been accepted for publication in the Journal of Ultrasound in Medicine. The National Institutes of Health supported the work.