This Spotlight describes the use of optical phantoms as validation tools for probe-based imaging and spectroscopy platforms. Composition of optical phantoms, including scattering and absorbing agents, is discussed in the context of their specific application. Next, requirements for designing optical phantoms for validation of small endoscopic instrumentation is presented including a discussion on the diffuse and sub-diffuse scattering regimes and how this relates to common types of epithelial tissue. This book concludes with a tutorial section for constructing solid phantoms to simulate thin epithelial tissue structure and liquid phantoms to extract tissue optical properties using probe-based reflectance spectroscopy techniques. For these applications, solid phantoms are made using poly(dimethylsiloxane) and liquid phantoms are made using deionized water as the substrate material. The scope of the book is limited to optical phantom design and application and is not intended to describe the physics, instrumentation, or mathematical or computational modeling of the various techniques mentioned in detail.
Optical phantoms are a widely used tool to validate optical instrumentation.
In essence, phantoms are "false tissues" made of various materials and can be
liquid, solid, or gelatinous. Generally, phantoms are made to either simulate a
tissue’s optical, mechanical, chemical, or physical properties, or a combination
of these. These structures are typically comprised of a base substrate material,
which can be doped with certain additives that give the material specific optical,
mechanical, or chemical properties. Additionally, depending on the substrate
material used and desired geometry, optical phantoms can be molded into a variety
of shapes and sizes for different applications.