Tim Hansen has been named CEO and a member of the board of Imaging Diagnostic Systems Inc., a Fort Lauderdale, Fla., developer of medical optical imaging technology, including a system that uses laser technology and algorithms to create 3-D cross-sectional images for the detection of breast cancer. Hansen replaces Linda B. Grable, founder and CEO, who has retired.    . . .    Quebec-based Advanced Research Technologies Inc., a maker of optical molecular imaging products for the healthcare and pharmaceutical industries, announced it has sold an eXplore Optix optical molecular imager to the University of Bergen, in Norway, through its exclusive worldwide distributor GE Healthcare. In addition to its focus on marine research, the university has established technology platforms for proteomics, molecular imaging, molecular modeling and bioinformatics. An optical imaging unit will be located in a new biomedical research building, which opened in September and connects the university to the Haukeland University Hospital.    . . .    Hologic Inc., a Bedford, Mass., provider of women's diagnostic imaging systems and digital imaging systems, announced it has entered into a collaborative research agreement with the David Geffen School of Medicine at the University of California at Los Angeles (UCLA) to study a variety of advanced breast imaging applications. The research will assess digital mammography workflow versus the conventional film method, the uses and efficiencies of a dedicated breast ultrasound system in a breast imaging practice and the effectiveness of computer-aided-detection in breast magnetic resonance imaging. They will also investigate new mammography technologies for clinical testing and evaluation for commercial release.