Determination of Finger Optical Properties Using an Integrating Sphere

Integrating sphere measurements are a well-established method for determining the optical properties of planar samples. In this study, the approach was expanded from slab geometry to cylindrical geometry illuminating the cylinder barrel, thereby demonstrating its applicability for determining the optical properties of human fingers. By adapting existing integrating sphere theory to cylindrical samples, the method was systematically validated using phantoms and subsequently applied to human fingers. It has been demonstrated that the absorption coefficient μa and the reduced scattering coefficient μs′ of cylindrical and 3D finger phantoms can be determined with a high degree of agreement to those of slab phantoms. Moreover, this approach facilitates the quantification of tissue components in human fingers, including fat, water and collagen content, total haemoglobin concentration and tissue oxygenation.