Optical properties of silicone rubber tissue phantoms for biomedical optics applications*

In medical physics, tissue phantoms play important role in characterization, validation, calibration and optimization of medical devices. A useful phantom must be well characterized, namely its physical properties must be accurately measured using standard techniques.

A set of silicon rubber tissue phantoms was prepared for applications in biomedical optics. A black pigment served as an absorber and hollow silica micro-spheres as scatterers. Nine samples with different absorber and scatterer concentrations were prepared. Refractive indices of the samples were measured in the 430 – 660 nm spectral range and did not vary significantly (<0.02 %). Optical properties (absorption and scattering coefficients, and similarity parameter γ) were estimated using spatially resolved reflectance spectroscopy in the subdiffusive regime (400 - 1000 nm). The determined optical properties covered the range characteristic for biological tissues.

Silicon rubber tissue phantoms feature many advantageous properties in comparison to other common phantoms in biomedical optics (e.g., intralipid, agar). They are stable, solid, reproducible, and their optical properties can be adjusted according to the application demands. Therefore, they are promising tools for biomedical optics.