Development and characterization of tissue-mimicking phantom materials for photoacoustic imaging

Sammanfattning: Tissue-mimicking phantoms are of great interest in the development of bio-medical applications. Instead of applying to biological tissues directly, phantoms enable stable and easy accessibility to validate spectroscopy systems and measuring processes. This thesis project is centered on the development and characterization of phantoms. The interaction between light and biological tissue is mainly characterized by the absorption and scattering coefficients. The propagation of light inside tissue can be described by the diffusion theory and Monte Carlo (MC) simulations. Spectroscopy methods such as the collimated transmission spectroscopy (CTS) and the photon time of flight spectroscopy (pToFs) were used to measure the optical properties of the phantoms. Previous research on phantom materials will be summarized. In particular, the styrene-ethylene/butylene-styrene (SEBS) copolymer was studied and used to produce oil-based phantoms for photoacoustic imaging (PAI). By adding oil-based colored ink and TiO2 to the gel mixture made with SEBS powder and paraffin oil, oil-based SEBS phantoms with tunable absorption and scattering coefficients were manufactured. Together with good time stability and easy reproducibility, test results from PAI showed that these SEBS phantoms were able to provide good image quality and depth resolution within the near infrared wavelength range.