Flash Scanning Volumetric Optoacoustic Tomography for High Resolution Whole-Body Tracking of Nanoagent Kinetics and Biodistribution

Abstract

Tracking of biodynamics across entire living organisms is essential for understanding complex biology and disease progression. The presently available small-animal functional and molecular imaging modalities remain constrained by factors including long image acquisition times, low spatial resolution, limited penetration or poor contrast. Here flash scanning volumetric optoacoustic tomography (fSVOT), a new approach for high-speed imaging of fast kinetics and biodistribution of optical contrast agents in whole mice that simultaneously provides reference images of vascular and organ anatomy with unrivaled fidelity and contrast, is presented. The imaging protocol employs continuous overfly scanning of a spherical matrix array transducer, accomplishing a 200 µm resolution 3D scan of the whole mouse body within 45 s without relying on signal averaging. This corresponds to an imaging speed gain of more than an order of magnitude compared with existing state-of-the-art implementations of comparable resolution performance. Volumetric tracking and quantification of gold nanoagent and near infrared (NIR)-II dye kinetics and their differential uptake in various organs are demonstrated. fSVOT thus offers unprecedented capabilities for multiscale imaging of pharmacokinetics and biodistribution with high contrast, resolution, and speed.