Poster — Thur Eve — 19: Polyvinyl Alcohol Cryogels: A Promising Material for Tissue‐Mimicking Optical Phantoms

Tissue‐mimicking phantoms with specific radiological, elastic, or optical properties are desirable for calibration and quality assurance purposes. Polyvinyl alcohol (PVA) is a non‐toxic, water‐soluble polymer with many existing uses in medicine, ranging from artificial tissues for use in humans to anatomical phantoms for magnetic resonance imaging and ultrasound. It has not been well characterized optically. The process by which the polymer is crosslinked, repeated freeze‐thaw cycles, imparts optical properties that lie in the range of tissue and can be selectively tuned using different production conditions. A double integrating sphere system has been constructed to measure diffuse reflectance and transmittance from an illuminated sample. Monte Carlo modeling of the measurement geometry allows for optical property estimation using the Marquardt‐Levenberg algorithm. The scattering by PVA cryogels increases with additional freeze‐thaw cycles. PVA scattering is also affected by the ambient conditions at the time of production. Most tissue scattering properties can be mimicked using 6 freeze‐thaw cycles at most.