Thermal and optical characterisation of SiliGlass phantoms.

Published on 29/05/2023

Urban Simoncic, Klemen Vrhovec, Iztok Prislan, Matija Milanic. 

In hyperthermal therapy, tissue phantoms play an 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. Silicon rubber tissue phantoms were prepared for applications in optical hyperthermal therapy. A black pigment served as an absorber and hollow silica micro-spheres as scatterers. Three samples with different absorber and scatterer concentrations were prepared. Optical properties (absorption and scattering coefficients) were estimated using hyperspectral imaging (400 – 1000 nm) and inverse Monte Carlo. Thermal properties, specifically heat capacity and thermal conductivity, were measured using differential scanning calorimetry. The obtained values were 1295– 1320 J/kgK for the heat capacity and 248– 266 mW/mK for the thermal conductivity. The estimated phantom parameters were experimentally tested on laser irradiation (532 nm laser) of the phantoms and a good agreement on the thermal relaxation with the theoretical predictions was obtained.Silicon rubber tissue phantoms are stable, solid, reproducible, and their optical and thermal properties can be adjusted according to the application demands. Therefore, they are promising tools for evaluation and development of optical hyperthermal therapies.