Abstract: Nuclear hypoxia imaging is a convenient and safe method which can provide qualitative and quantitative information of oncology hypoxic degree. The commonly used imaging agent have two categories. Nitroimidazole agent, which effective group (-NO₂) reducted in the hypoxia cell can not be reoxidized and be detained in it. Nonitroimidazole agent, which imaging mechanisms are different according to different agents. This technology is useful to formulate reasonable radiotherapy plan and evaluate radiotherapy effect.