academy of science news in the st. Louis Zoo won't you please join me in welcoming dr. Lee hongwol well thank you rose for the very kind introduction thank you all for coming here tonight I'll be talking about several technologies we've been working on in our lab our goal is to image biological tissue using optical contrast starting from the motivations and challenges in our field in general I'll be talking about two major incarnations of photoacoustic tomography namely photoacoustic computed tomography and photo acoustic microscopy then I'll talk