Ultrasonic Vision Appears to Make Body Translucent

The device shows promise for use in guiding invasive procedures.

Currently, doctors use ultrasound to guide invasive procedures, such as inserting a needle into a vein. However, to do so they must look away from the patient to view the ultrasound display screen. This causes a displaced sense of hand-eye coordination, says the inventor, George Stetten, M.D., Ph.D., assistant professor of bioengineering at the University of Pittsburgh (UPMC, PA, USA). The prototype device creates the effect of a translucent ultrasound image floating in its actual 3-D location within the patient, showing blood vessels, muscle tissue, and other internal anatomical features.

To obtain this effect, Dr. Stetten positions an ultrasound scanner and the ultrasound display on opposite sides of a half-slivered, translucent mirror. The viewer looks through the mirror to see the patient and the ultrasound scanner positioned on the patient's skin. At the same time, the ultrasound image is projected on the viewer's side of the mirror in perfect alignment with the corresponding location within the patient's body. This makes the ultrasound image appear to occupy the same physical space as the body part being imaged. If the viewing angle changes, the combined images remain true.

Dr. Stetten calls the process tomographic reflection. The image could help surgeons perform needle biopsies, catheterizations, surgery and other procedures while looking directly at the patient. The research was reported in the March 2001 issue of Journal of Ultrasound in Medicine. "We are actually merging the virtual image in 3-D with the interior of the patient,” he noted. "The reflected image is optically indistinguishable from the corresponding space within the patient.”




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