Quick, nurse, a flashlight

ASEE Prism, Oct 2002

Ultrasound has been in use for many years now, and it's proven to be a boon in giving physicians an inside look at our innards. Ultrasound bombards the body with high-frequency sound waves. When they bounce back, they can be read to provide a detailed image of muscle, blood vessels, and other "soft" parts of our anatomy. But ultrasound still has drawbacks when used to guide doctors during invasive procedures, like needle biopsies, catheterizations, surgery, or just giving injections. That's because it requires them to look away from the patient and at a computer screen.

Now, a researcher in Pittsburgh is developing what he calls the Sonic Flashlight, which uses a half-silvered mirror to reflect back onto the patient the image showing up on the flat-screen monitor. The image superimposed on the patients in real time, corresponds precisely to the part of the body being scanned. This will allow doctors to keep their eyes glued on the patient, and simultaneously see what they're doing both externally and internally. George D. Stetten, a bioengineer at both the University of Pittsburgh and Carnegie Mellon University, has devised two versions of the Sonic Flashlight-a larger stationary machine, and a portable, handheld device for use in doctors' offices. He calls the process "tomographic reflection" and is encouraged by experiments on butchered meat and a cadaver. "We are proposing animal tests to the NIH," says Stetten, who is also a medical doctor. No license for the technology has yet been issued, so he guesses it will be "a number of years before it may become standard equipment."