Lymphatic mapping

(lim-FA-tik ...) The use of dyes and radioactive substances to identify lymph nodes that may contain tumor cells. Also called lymph node mapping.

(lim-fat'-ick map-eeng) involves injecting a small amount of a radioisotope localization solution into the area near the breast tumor. This radioisotope localization solution allows the surgeon to trace the pathway of drainage from the area around the breast cancer tumor. The physician then uses an instrument called a gamma detector which looks for the lymph node where the solution collects. The radioisotope is injected before surgery and sometimes again during surgery. The second part of lymphatic mapping involves the injection of a blue dye into the area near the breast tumor. This is done at the beginning of the surgery. The physician then makes a small incision (opening through the skin) in the axilla and searches for a blue lymph node and the blue-stained channels leading to the node. For more information, see Sentinel Lymph Node Dissection.