Development and investigation of the acoustic properties of tissue-mimicking materials for photoacoustic imaging techniques

Phantom test devices are used in the development of medical imaging modalities to gain a more complete understanding of the underlying physical processes and to optimize techniques. There are currently no standard photoacoustic imaging (PAI) phantoms, although there is a move towards standardization, notably in a new international consortium (IPASC) focusing on the standardization of PAI techniques and phantoms. The use of gel wax/copolymer in oil materials in PAI is relatively recent with only limited studies carried out, however such materials hold promise for wide-spread adoption as a phantom material due to ease of preparation and extensive component availability. A standardized preparation method for the material has yet to be published. This work describes an investigation of the acoustic properties of various preparations of the bulk material. The final material consisted of 84.49 % mineral oil (light), 12 % Polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene 3 % low density polyethylene, 0.05 % TiO2 and 0.46 % Benzalkonium chloride and had stable acoustic properties mimicking fatty soft tissue over 6 months, with a phase velocity of 1464.2 +/- 0.4 m s.1 and mean attenuation of 4.04 +/- 0.2 dB cm(-1) at 5 MHz.