SAN JOSE, Calif., Jan. 30 -- Photonics West 2003 opened with BiOS, the biomedical optics symposium, featuring 27 conferences focused on an array of technical areas: clinical treatment and diagnostics and clinical technologies and systems, tissue engineering and science, spectroscopy, microscopy, and imaging, and biomolecular and cellular analysis. Attendees were treated to a standing room-only presentation on Saturday night, the BiOS Hot Topics, moderated by Sergio Fantini (Tufts Univ.). Britton Chance (Univ. of Pennsylvania), Peter So and Jim Fujimoto (MIT), and Bruce Tromberg (Beckman Laser Institute and Medical Clinic) were among the speakers regaling the crowd with tales of recent advances and promises in tomography, noninvasive study, spectral imaging, and bioMEMs. The Biomedical Optics Exhibition gave attendees a glimpse into the current state of instrumentation and devices. Fifty companies and 500 exhibit-only attendees kept the floor busy throughout the show.