Nanoparticle-free tissue-mimicking phantoms with intrinsic scattering.

We present an alternative to the conventional approach, phantoms without scattering nanoparticles, where scattering is achieved by the material itself: spherical cavities trapped in a silicone matrix. We describe the properties and fabrication of novel optical phantoms based on a silicone elastomer polydimethylsiloxane (PDMS) and glycerol mixture. Optical properties (absorption coefficient µa , reduced scattering coefficient µs' , and anisotropy factor g) of the fabricated phantoms were retrieved from spectrophotometric measurements (in the 400-1100 nm wavelength range) using the inverse adding-doubling method. The internal structure of the phantoms was studied under a scanning electron microscope, and the chemical composition was assessed by Raman spectroscopy. Composition of the phantom material is reported along with the full characterization of the produced phantoms and ways to control their parameters.