Optical Properties of Porcine Skin and Subcutaneous Tissue Following Various Methods of Cold Storage

Accurate values of the optical properties of skin and subcutaneous tissues are critical for a variety of applications, such as optical imaging techniques and computational modeling of possible hazardous laser exposure. Several studies are available in the published literature that report skin optical properties, but the method of tissue preparation and storage in these experiments can be variable, ranging from measurement immediately after excision, to undergoing some form of cold storage, such as refrigeration or freezing. The degree to which cold storage affects the optical properties of skin tissues is unknown. We measured the absorption and reduced scattering coefficients of skin and subcutaneous tissues that underwent refrigeration and slow freezing, and compared them to freshly excised samples. Tissues were collected from several subjects in order to capture biological variability. We employed a goniometric spectrophotometer setup and a Monte Carlo light propagation method to determine optical properties. The results of this investigation will help contextualize existing studies on tissue optical properties and enable informed procedural design for future measurements.