Ultrasound tagged light imaging in turbid media in a reflectance geometry

A combination of light and focused ultrasound waves provides a unique way t o obtain directly three-dimensional absorption data in a. turbid medium. We present the combination of an ultrasound wave and light in which both the input and the output optodes are on the same side of the sample (reflectanc e geometry). This technique permits local detection in depth of the presenc e of a purely absorbing object, without further mathematical processing. It is a promising technique for medical imaging and monitoring of tissues. (C ) 2000 Optical Society of America OCIS codes: 030.6140, 170.5270, 170.7050, 110.7170, 170.3880.