Lymphatic system and sentinel lymph nodes

Here, we use a radioactive material, called a radiopharmaceutical or radiotracer, which is injected beneath the skin. This radioactive material accumulates in the lymph stream, where it gives off a small amount of energy in the form of gamma rays. Special cameras detect this energy, and with the help of a computer, create pictures offering details on both the structure and function of the lymphatic system. Both lymph channels and lymph nodes are visualized.

This examination is used to assess the permeability of lymph channels in diseases of the lymphatic system (lymphostasis). Furthermore, this method is used to locate the first lymph node or group of nodes draining a cancer (sentinel lymph node). It can be expected that the tumor cells have been moved further through the lymph vessels, if the sentinel lymph node and subsequent nodes contain tumor cells.