Noinvasive photoacoustic tomography in biological tissue with ultrasonic probe beam

A noinvasive method for photoacoustic tomography of medical diagnoses by using an ultrasonic probe beam is presented.When a pulse laser irradiates on biological tissues,a plane ultrasonic probe beam passes through the irradiated area,and the ultrasonic probe beam interacts nonlinearly with photoacoustic tomography wave.Abundant information can be taken out from the interaction area by demodulating the probe beam.On one hand,the information can reflect the optical properties of the tissue;on the other hand,it can also reflect acoustical properties of the tissue.In the experimentation,the circular measurement configuration combined with the filtered back projection(FBP) algorithm,very high signal-to-noise ratio tomography images can be obtained.For the laser energy can be absorbed by the identity molecule of the tissues,it will provide a potential non-invasive imaging technique for biomedical diagnosis and functional imaging.