Relation Between Ultrasound-modulated Optical Signal And Tissue Optical Properties

Ultrasound modulated optical tomography combines the advantages of light with ultrasound and is able to image objects embedded in turbid medium. It is a promising technique, which possesses characteristics of high imaging contrast, high resolution, noninvasive and can be used for vivo imaging. It is expected to be a preferred imaging technology for shallow biological tissue.A relationship between the modulated optical signal and the optical parameters of tissue inside and outside of the ultrasound zone is given by experiment. It is discovered that the modulation depth is directly relevant to the optical properties of the tissue at the ultrasound focal zone. The modulation depth increase as the scattering coefficient of sample increases, and increases with the increase of absorption coefficient. The modulation depth of signal is not subject to the optical properties of complex tissue outside of the ultrasound zone. At last, based on Photomultiplier Tube (PMT), one-dimension imaging of the sample is obtain. All these results will provide necessary basis for further image reconstruction of Ultrasound-modulated optical tomography.