Biomedical Applications of Integrating Sphere: A Review

Integrating sphere remains a valuable tool for biomedical optics research. Specifically, it has been used to determine the optical properties (i.e., absorption coefficient, scattering coefficient and anisotropy factor) of biological tissues. This study presents an overview of the literature on integrating sphere and its biomedical applications. In particular, we start with a brief introduction of tissue optics with emphasis on the optical properties of biological tissues, followed by a detailed discussion of the hardware and related procedures of the integrated sphere system. Both the experimental procedure and subsequent analytical models (i.e., first order scattering, Kubelka Munk, diffusion approximation, Monte Carlo and inverse adding-doubling methods) along with illustrative examples are also outlined. Finally, illustrative examples to explore the optical properties of tissue phantoms and biological samples have been discussed. This survey will provide a ready reference and overview for the applications of integrating sphere in biomedical optics.