A parallel excitation based fluorescence molecular tomography system for whole-body simultaneous imaging of small animals.

Challenges remain in imaging complete dynamic physiological processes in vivo through the whole small animal body using fluorescence molecular tomography (FMT). In this article, a novel non-contact full-angle FMT system that enables whole-body simultaneous imaging of small animals is presented. The whole-body simultaneous imaging ability is achieved by employing a line-shaped parallel excitation source, which can provide extended spatial sampling dataset to reconstruct multiple fluorescent targets distributed in whole animal body during one full-angle FMT imaging process. The key performances of this system were evaluated by a series of experiments. Quantitation linearity for over two orders of magnitude of fluorescence markers concentration was demonstrated, and an accessible simultaneous imaging domain of 4.0 x 1.5 cm² could be achieved utilizing the parallel excitation pattern. Moreover, the in vivo imaging feasibility and performance were validated by localizing two fluorescent targets implanted at different positions of a nude mouse. The results suggest that compared with conventional single point excitation FMT system, the proposed system can achieve a whole-body simultaneous imaging domain and impart the ability to image complete dynamic physiological processes in vivo.