LASER REFLECTANCE IMAGING OF HUMAN ORGANS AND COMPARISON WITH PERFUSION IMAGES

Based on the principle of backscattering of laser radiation from tissu es, a noninvasive PG-AT based reflectance imaging technique is develop ed. The laser beam from a semiconductor laser operating at 670 nm is g uided to the tissue site by an optical fibre. The backscattered radiat ion is collected by another fibre placed in the same probe, and is det ected by a photodiode-amplifier assembly. This probe is moved manually over the organs under observation, and the data after the ADC, interp olation and median filtering are displayed in the form of reflectance image of the organ along with grey scale. By this technique images of the human hands and forearms are obtained, which depend on the variati ons in their colour, composition and blood flow. A comparison is made with perfusion images, obtained by a Periflux laser Doppler flowmeter. These show that the reflectance images provide greater details of the tissue structure than the perfusion images.