Design and evaluation of a continuous-wave diffuse optical tomography system

Diffuse optical tomography (DOT) can image spatial variations in highly sca ttering optical media. We have built an inexpensive and portable continuous -wave DOT system containing 18 laser diode sources (9 at 780nm and 9 at 830 nm) and 16 silicon detectors, which can acquire 288 independent measurement s in less than 4 seconds. These data can then be processed using a variety of imaging algorithms. We first discuss the design of diffuse imaging equip ment in general, and then describe our instrument, along with the technical issues that influenced its design. The technical challenges involved in pe rforming DOT over large optode areas are discussed. We also present rat bra in measurements following electrical forepaw stimulation using DOT. These r esults clearly demonstrate the capabilities of DOT and set the stage for ad vancement to quantitative functional brain imaging. (C) 1999 Optical Societ y of America.