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Significance: Oral squamous cell carcinoma (OSCC) has an exceptionally high rate of incidence and mortality in India, with 15 cases per 100,000 people and over 70,000 deaths annually. The problem is exacerbated due to insufficient medical infrastructure for widescale screening and oncology care, particularly in rural regions. New technologies are urgently needed to detect oral cancer and provide timely treatment at the point of care. This work draws upon previous development and clinical validation of low-cost hardware for photodynamic therapy (PDT) treatment of oral lesions combined with an intraoral probe for cancer screening, incorporated here into an integrated theranostic device for image-guided PDT. Aim: This study aimed to validate technical performance of a novel hand-held smartphone-coupled intraoral device designed for simultaneous imaging and photodynamic therapy (PDT) of oral lesions. The imaging and PDT light delivery capabilities of the handheld system were evaluated using tissue phantoms containing protoporphyrin IX (PpIX) and a mouse model of OSCC photosensitized using 5-aminolevulinic acid (ALA)-induced PpIX. Approach: The probe’s built-in multi-channel fluorescence and polarized white light imaging capabilities were evaluated using tissue phantoms with TiO2 and controlled PpIX concentrations. In-vivo testing was performed using mice with subcutaneous TR146 OSCC implants before and after administering ALA, and again to assess photobleaching after light delivery (a total of 100J/cm2 at 635nm from the integrated diode laser). Results: Quantification of fluorescence images generated using the device showed that the PpIX signal scaled linearly with concentration, and the extent of photobleaching increased with increasing PDT dose as expected. In murine xenografts, PDT treatment delivered through the intraoral probe reduced tumor volume significantly in comparison to untreated control animals. Conclusion: Our findings demonstrate the effectiveness of a low-cost handheld device for simultaneous quantitative imaging of PpIX fluorescence and image-guided PDT in vivo. The integration of intraoral imaging and image-guided treatment into the same handheld device paves the way for a streamlined approach to cancer screening and early intervention with PDT at the point of care.
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