[en] The clinical observation of a case of extremely severe local radiation injury by extremely heterogeneous external irradiation of ¹⁹²Ir is reported. The clinical pathologic change was systematically observed, and the temperature changes in the radiation injured parts were examined by infra-red thermo-imaging. Numbness and convulsion occurred 2 h after irradiation, the earliest erythema and swelling were found 4 h after irradiation. Blistering took place 54 h after irradiation, necrosis and severe pain occurred at the 5th day, the latest erythema and swelling were found 41 days after irradiation, and severe pain occurred at the 5th day, the latest erythema and swelling were found 41 days after irradiation, and blistering and erosive surface of wound took place at the 47th day. Infra-red thermo-imaging examination showed that temperature increased in the early stage of injury, while it decreased in blisters, necrotic regions and in the later stage of injury. The earlier the temperature increased, the severer the injury was. The region of temperature change was consistent with injury extent. Incipient reaction occurred early, injury was exacerbated by radiation sickness and local injury, symptoms were different in early and late stages and varied in severity, the disability was high and pain was severe. The temperature change during infra-red thermo-imaging can be used as one of the objective indices for the diagnosis of injury extent and degree