Like Tc-99m-MAA (macroaggregated albumin),  Tc-99m-nanocolloids are made from human serum albumin. Particle size, however, is much smaller than MAA (≤80 nm versus 20–100 μm), so after i.v. injection nanocolloids traverse the lungs, enter the circulation and are cleared into the macrophages of the reticuloendothelial system (RES; liver, spleen and bone marrow). Imaging the RES is a minor clinical indication for Tc-99m-nanocolloid, which instead is more frequently used in lymphoscintigraphy for the diagnosis of lymphatic dysfunction in a swollen limb or the identification of the sentinel lymph node in cancer. The diagnosis of lymphatic dysfunction rests on the 3 Ds - delay (in the arrival of tracer in locoregional lymph nodes), diversion (of tracer into skin or deep draining system as opposed to epifascial drainage) and damage (of lymphatic vessels leading to tracer exudation and formation of lymph lakes).