Three-dimensional radiopharmaceutical-excited fluorescence imaging of lymph nodes

Optical imaging techniques have been developed for localizing lymph nodes before surgical resection due to the non-invasion and high sensitivity. However, its attendant penetrability limitations and auto-fluorescence effect have greatly limited the spatial resolution and imaging precision. In this study, a novel technique radiopharmaceutical-excited fluorescence imaging (REFI) was adopted to image lymph nodes, which use gamma-ray and Cerenkov radiation from radioisotopes to excite lanthanide europium oxide (EO) nanophosphors and boost the light intensity. An effective adaptive-steepest-descent-projection onto convex sets (ASD-POCS) reconstruction algorithm and the anatomic structure information were used to three-dimensionally image lymph nodes in mice models. The results indicate that REFI can greatly boost the light intensity and accuracy of three-dimensional imaging of lymph node with location deviation less than 1.03 mm.