Using paired-agent principles and widefield fluorescence optical projection tomography to rapidly identify and...

The proof-of-concept presented here utilizes a micro metastatic lymph node mode, where porcine lymph nodes are first implanted with a 200-micron human cancer cell spheroid. The lymph nodes are then infused with 40 nM ABY-029 and IRDye 700Dx-Affibody isotype conjugate, followed by widefield multi-channel imaging of 700 nm, 800 nm fluorescence and transmission images across 12 projections, followed by tomographic reconstruction of each channel. Absorption and fluorescence sensitivity matrices needed for reconstructions are created through monte-carlo simulations of photon propagation through the imaging system. Each channel is reconstructed separately at a resolution of 87x87x65 voxels, followed by calculation of binding potential (BP) maps as the ratio of the two fluorescence reconstructions, minus 1. The BP reconstruction is then overlaid onto the absorption reconstruction and the location of the EGFR+ tumor spheroid is isolated in the 3D reconstruction through inspection. These procedures are proposed for intraoperative use.