Image-guided PDT for oral lesions: Technology development, evaluation and translation

Oral cancer is the sixth most common cancer worldwide and mortality rates have increased steadily over the past three decades. Clinical studies by ourselves and others have shown that PDT is an effective non-surgical alternative for treatment of early-stage oral cancers and precancerous lesions, though a lack of any standardized protocols and robust enabling technologies have limited its adoption. Here we report the development a platform which integrates PDT light delivery into a handheld intraoral imaging device that enables simultaneous visualization and treatment guidance based on white light, tissue autofluorescence, and photosensitizer fluorescence signals. Using animal models and phantoms we demonstrate the capability of this system for quantitative imaging of ALA-induced PpIX photosensitization, assessment of lesion margins by ratiometric analysis of PpIX and autofluorescence signals, and near real-time read out of surface photobleaching during light delivery as a corollary of dose deposited in target tissue.