Use of an agent to reduce scattering in skin

Abstract

Background 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 properties of rat and hamster skin were investigated. Study Design/Materials and Methods: A hyperosmotic agent, glycerol, was applied in vitro and in vivo to rat and hamster skin to assess the changes in tissue optical properties. Changes in the reduced scattering coefficient after application of the agent in vitro to rat skin and after the skin has been rehydrated were assessed to evaluate the effect of the agent on tissue. Results: Experimental results showed a transient change in the optical properties of in vitro rat skin. A 50% increase in transmittance and decrease in diffuse reflectance occurred within 5-10 min after the introduction of anhydrous glycerol. In addition, reduction of light scattering with this technique increased depth of visibility with optical coherence tomography. Injection of glycerol under the skin allowed in vivo visualization of blood vessels. Conclusions:The application of the agent reduces the amount of refractive mismatch found in the tissue and markedly reduces random scattering, thereby making the skin less turbid for visible wavelengths for a controlled period of time.

Optical clearing of the skin for near-infrared fluorescence image-guided surgery

“…Topically applied hyperosmotic agents have been used as optical clearing materials in previous studies utilizing both optical coherence tomography (OCT; (2,22–24)) and low-level emitted light (bioluminescence) imaging (25). Although it is possible that OCT may be more sensitive to alterations of light penetration induced by glycerol than NIR imaging, it is also possible that dehydration from air exposure during the procedure is creating a situation analogous to our non-hydrated ex vivo samples, and that glycerol is acting to change the hydration status of the tissue (2,4,6,26).…”

Evaluation of laser beam profile in soft tissue due to compression, glycerol, and micro‐needling

“…Since Vargas et al [5] first reported optical tissue clearing by glycerol, HCAs have been frequently utilized as an effective method to reduce light scattering of tissue and, therefore, improve optical tissue clearing. HCAs have been shown to induce optical tissue clearing by skin dehydration and collagen dissociation or a combination thereof [6,7].…”

Modulated Fluorophore Signal Recovery Buried within Tissue Mimicking Phantoms

“…9–12 Such resolution recovery schemes can be further enhanced through locally incorporating optical clearing chemical agents 13–16 or producing mechanical compression by reducing refractive index mismatch between compact proteins to improve optical transmission. 17 These innovations, however, are unable to minimize the background signals coming from tissue auto-fluorescence, and often sacrifice total signal for resolution improvement.…”