Journal Article photoacoustic imaging Biocompatible Materials Fluorescent Dyes Lanthanoid Series Elements MRI NIR-II NIR-II fluorescence imaging NIR-IIb fluorescence Polymers Research Support, Non-U.S. Gov't aggregation-induced emission bio-orthogonal labeling brain tumor brain tumors cerebrovascular structures early-stage brain tumors fluorescence and photoacoustic imaging focused ultrasound lanthanide-doped nanoparticles nanoparticles photothermal therapy precision theranostics second near-infrared window tumor imaging