Trimodal spectroscopy (TMS): Reflectance, fluorescence and light scattering spectroscopy for the detection of epithelial dysplasia

Currently, clinical screening for pre-cancer (or epithelial dysplasia) relies on visual detection of suspicious areas followed by invasive biopsy and microscopic examination. Given that visually identified suspicious areas do not always correspond to clinically significant lesions, new diagnostic methods could prevent unnecessary invasive biopsies and potential delays in diagnosis. Furthermore, real-time detection and diagnosis of lesions could pave the way for combined diagnosis and treatment sessions, thus preventing unnecessary follow-up visits.

Trimodal spectroscopy (TMS) utilizes reflectance and fluorescence spectroscopies to provide a real-time diagnosis of pre-cancerous lesions in vivo. The figure below illustrates the process of the TMS spectral diagnosis. The fastEEM reflectance spectrofluorimeter collects both white light reflectance and fluorescence excitation-emission matrices (EEM’s) in a fraction of a second. These spectra are then analyzed in three modalities: intrinsic fluorescence, diffuse reflectance and light scattering spectroscopy. Spectral algorithms provide quantitative tissue parameters such as biochemical constituents, hemoglobin concentration, oxygen saturation, and epithelial nuclear morphology. A diagnostic algorithm then provides a diagnosis.

TMS has been used to diagnose dysplasia in several organ sites: uterine cervix, gastrointestinal tract, and oral cavity. In addition, we have used combined fluorescence and reflectance to characterize atherosclerotic plaques.