Lymph nodes from the dissected neck and serial scintigraphy. Four lymph nodes are shown from the dissected neck of a rat (A, upper left). Only one lymph node was observed as fluorescent in the dissected neck (A, upper right). Four lymph nodes were excised (A, lower left). Fine spatial distribution of the fluorescence was observed in one of the four lymph nodes (A, lower right). Serial scintigraphy of a rat after PCSN probe injection. Increased neck accumulation was observed at 10, 20, 30, 40, 50, and 60 min after injection; these time points are numbered 1 to 6, respectively (B).