Molecular-targeted photoacoustic and fluorescence imaging in a pre-clinical head and neck cancer model (Conference Presentation)

Surgical resection is the primary treatment method for head and neck cancers, but accurately delineating tumor margins during surgery is challenging. Molecular marker-targeted fluorescence imaging can improve margin delineation on the tumor surface and IRDye800-conjugated anti-EGFR antibodies are being currently evaluated in several clinical trials for intraoperative fluorescence imaging. However, delineating tumor depth can still be difficult. This study compares fluorescence and photoacoustic (PA) imaging enabled by a cetuximab-IRDye800 conjugate in xenograft models. Results show fluorescence signals increase up to 120 hours post-administration, while PA signals peak relatively early. We show that PA signal intensity is sensitive to cetuximab-IRDye800 localization, with tumor cell surface localization at early time-points yielding higher signal intensity as compared to internalized cetuximab-IRDye800 at later time-points. This study provides evidence to reconsider timing of PA imaging for improving PA signal intensity.