ECT is an emission-based electronic computed tomography scanner, mainly used in large hospitals above the tertiary level, which is a method of examination using radionuclides. It introduces radioactive drugs into the human body, and after metabolism by the body, a difference in the concentration of radioactivity is formed between the lesion site and normal tissue, and then these differences detected are processed by a high-energy electronic computer and then imaged for clinical diagnosis. It is mainly used for the examination of some tumors such as thyroid cancer, bone, etc. It is especially commonly used for the detection of bone metastasis tumors, such as breast cancer, lung cancer, prostate cancer, and esophageal cancer, etc.