A new device that projects the position of veins directly onto a patient's skin is helping take the guesswork out of medical pricks and injections.

VeinViewer shines harmless near-infrared light onto a patient's skin. The light's photons are absorbed by red blood cells inside vessels, but bounced back by surrounding tissue.

The reflected photons are captured by a digital video camera and a computer creates a digital image of the vasculature, which is then projected back onto the patient's skin.

• Click here to visit FOXNews.com's Human Body Center.

The hidden veins appear on the skin as colorless lines that crisscross a rectangular patch of neon green.

The technology works regardless of a patient's age, body type or skin color, VeinViewer's creators say, and it is accurate to about a quarter of an inch.

Made by Luminetx Corporation, VeinViewer is being tested in hospitals across the country and was demonstrated last week at Wired Magazine's NextFest new-technology forum in New York City.

Copyright © 2006 Imaginova Corp. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed.