Multiwavelength focused ultrasound-optics system for measuring concentration changes in the focused area

The multiwavelength focused ultrasound (FUS)-optic technique in development aims to provide application for spatially accurate measurements of tissue properties in the focus area in real-time. But setting up such a system is quite challenging due to several factors, for instance the integration of different optical sources, positioning of the optical and acoustic beams on the phantom, and synchronization. In this presentation, we present first steps towards designing a multiwavelength FUS-optic system that measures wavelength dependent changes in the focus area. As a test substance, we used intralipid solution, milk, and the mixture with different levels of concentration. The expected signal peak heights of tagged photons intensities of different wavelengths are partly dependent on the concentration due to the wavelength-dependent optical absorbance. Furthermore, detected FUS modulated amplitudes are in relation with the concentration of sample in focus area. The aim of this study is to characterize the relationship between FUS-optic signal peak heights and the different levels of sample concentration at different wavelengths.