Immunoscintigraphy incorporates Tc into a monoclonal antibody, an immune system protein, capable of binding to cancer cells. A few hours after injection, medical equipment is used to detect the gamma rays emitted by the Tc; higher concentrations indicate where the tumor is. This technique is particularly useful for detecting hard-to-find cancers, such as those affecting the intestines. These modified antibodies are sold by the German company Hoechst (now part of Sanofi-Aventis) under the name Scintimun.