Radiopharmaceuticals in sentinel-lymph-node detection

Lymphoscintigraphy is commonly used for intraoperative identification of sentinel lymph nodes. Several radiopharmaceuticals have been developed and their organ specific differences of distribution were demonstrated. Reliable identification of sentinel nodes and their afferent lymph channels requires early imaging. The transport of colloids into lymphatic vessels substantially depends on particle size and surface characteristics. 99mTc-bound tracers suited for lymphoscintigraphy with a median size of about 20-100 nm demonstrate reliable transport from the interstitium to initial lymph vessels and lymph node uptake, because these agents demonstrate faster washout rates from injection sites and better definition of lymph nodes than other particulate agents. (orig.)