An optical
examination technique employs an optical
system (15, 45, 100, 150, 200, 260 or 300) for
in vivo, non-invasive examination of internal tissue of a subject. The optical
system includes an
optical module (12 or 14), a controller and a processor. The
optical module is arranged for placement on the exterior of the
abdomen or chest. The module includes an array of optical input ports and optical detection ports located in a selected geometrical pattern to provide a multiplicity of
photon migration paths targeted to examine a selected tissue region, such as an internal organ or an
in utero fetus. Each optical input port is constructed to introduce into the examined tissue visible or
infrared light emitted from a
light source. Each optical detection port is constructed to provide light from the tissue to a
light detector. The controller is constructed and arranged to activate one or several light sources and light detectors so that the
light detector detects light that has migrated over at least one of the
photon migration paths. The processor receives signals corresponding to the detected light and forms at least one
data set used for tissue examination.