Use of an agent to reduce scattering in skin

Bachground and Objective: A method to increase light transport deeply into target areas of tissue would enhance both therapeutic and diagnostic laser applications. The effects of a hyperosmotic agent on the scattering propert ies of rat and hamster skin were investigated. Study Design/Materials and Methods: A hyperosmotic agent, glycerol, was app lied in vitro and in vivo to rat and hamster skin to assess the changes in tissue optical properties. Changes in the reduced scattering coefficient af ter application of the agent in vitro to rat skin and after the skin has be en rehydrated were assessed to evaluate the effect of the agent on tissue. Results: Experimental results showed a transient change in the optical prop erties of in vitro rat skin. A 50% increase in transmittance and decrease i n diffuse reflectance occurred within 5-10 min after the introduction of an hydrous glycerol. In addition, reduction of light scattering with this tech nique increased depth of visibility with optical coherence tomography. Inje ction of glycerol under the skin allowed in vivo visualization of blood ves sels. Conclusions: The application of the agent reduces the amount of refractive mismatch found in the tissue and markedly reduces random scattering, thereb y making the skin less turbid for visible wavelengths for a controlled peri od of time. Lasers Surg. Med. 24:133-141, 1999. (C) 1999 Wiley-Liss, Inc.