RECENT ADVANCES IN COHERENT DETECTION IMAGING (CDI) IN BIOMEDICINE - LASER TOMOGRAPHY OF HUMAN TISSUES IN-VIVO AND IN-VITRO

We review the advantages of the optical heterodyne detection-based coh erent detection imaging system, for transillumination laser computed t omography (CT) in biomedicine using CW and single-frequency lasers as light sources, The unique properties of the coherent detection imaging system such as excellent directionality, selectivity, and high sensit ivity are exploited to differentiate and detect the minimally deviated on-axis/near-axis photons emerging from a tissue enabling the reconst ruction high-resolution laser CT images, Our recent progress on the ap plications of the coherent detection imaging system to laser CT of hum an fingers in vivo and calcified tissues in vitro at different wavelen gths in the visible and near-infrared regions are described. The laser CT images are obtained with low incident power of a few milliwatts an d are comparable to conventional imaging techniques, The internal laye rs of the imaged tissues could be clearly differentiated and identifie d with submillimeter resolution, We propose that further refinements i n the coherent detection imaging system could lead to a novel and pote ntial diagnostic tool in dentistry, osteology, and bone and joint rela ted diseases and disorders.