Purpose;

This study is to compare the ability of optical biopsy (where light enters the skin, is reflected back out, collected, analyzed by the computer, and a picture created for the pathologist to conventional histologic examination (where the pathologist looking at the piece of tissue through a microscope makes the diagnosis.) This non-invasive, non-contact technique has great potential as a means to diagnose different skin problems without the need to obtain a piece of tissue from the skin.

Hypothesis;

Photon Migration Spectroscopy (PMS) on each area of interest as identified by the physician. Photon Migration Spectroscopy is a non-invasive optical technique that utilizes intensity-modulated, near-infrared (NIR) light to quantitatively measure optical properties in thick tissues. Optical properties (absorption, µa, and scattering, µs', parameters) derived from PMS measurements shown low-resolution functional images of tissue hemoglobin (total, oxy, and deoxy forms), oxygen saturation, blood volume fraction, water content, fat content and cellular structure. PMS is currently employed in a number of other investigations including HS #1995-563 "Measurement of Breast tissue properties", HS#2002-2306 "Monitoring the response of chemotherapy on breast tumor" and HS#2004-3626 "Measurement of the Distribution of Optical Properties in Adult Human Muscle"

MI, multispectral imaging system operates by projecting low-power near-infrared structured light patterns on to the tissue of interest in a non-contact, reflection geometry and then capturing the reflectance with a CCD camera. The system can image the depth-resolved optical properties of in-vivo tissues, allowing rapid, non-invasive 3D visualization of sub-surface structures. Moreover, while this system is low-resolution (~0.3mm) compared to OCT, it has a high sensitivity to functional parameters related to hydration and inflammation, making it complimentary to OCT.

The multispectral device uses a near-infrared tungsten-halogen bulb with heat filtering for tissue illumination, resulting in an optical power of <10mW/cm^2 in any 10nm band ranging from 600-1000nm. This is analogous to illumination with a bright flashlight, and will not inflict any pain or injury to the rat during the procedure. A CCD camera will capture the reflected light of various spatial illumination patterns over an area of 1cm^2 from a depth ranging from 0-4mm.