Synthesis and evaluation of an 111In-labeled porphyrin for lymph node imaging

111In-labeled tetra(4-N-methylpyridyl)porphyrin was investigated as a possible lymph node imaging agent. A clinically feasible method for the preparation of this radioactive pharmaceutical was developed from experiments with the synthesis and characterization of the unlabeled complex. The in vivo distribution of the compound in Wistar rats was determined as a function of time. Favorable lymph node-blood, lymph node-muscle, and specific lymph node-surrounding tissue ratios were obtained.