Figure 8.

Molecular imaging using radiolabeled upconversion nanoparticles. The radiolabeled upconversion nanoparticles were injected in the rear left footpad and imaged in six different modalities at 1 h p.i. Accumulation of the nanoparticles in the first draining lymph node is indicated with yellow arrows. A) Traditional fluorescence; B) upconversion image; C) PET image; D) merged PET/CT image; E) chemiluminescence image; F) photoacoustic images before and after injection show endogenous photoacoustic blood signal compared to the contrast enhancement that allowed visualization of the previously undetected lymph node. Adapted from Rieffej et al.¹⁰⁴