Internal dosimetry: challenges in biokinetic modelling and decorporation of radionuclides

Radiation exposure, both external and internal, may occur during the operation of various nuclear fuel cycle facilities and radiation facilities. Internal dose is the radiation exposure that results from the intake of radioactive materials into the body by inhalation, ingestion, absorption through the skin or via wounds. Assessment of internal doses can be divided into two phases, namely determination of the amount of radioactive material in the human body, in body organs or wounds by direct measurements and/ or by indirect methods like excretion analysis or air monitoring followed by interpretation of the monitored data in terms of intake and/or internal dose. Determination of internal doses is a complex procedure that requires the use of biokinetic and dosimetric models which describe the behavior of the radionuclides and the deposition of their energy in the tissues. In the present talk, ICRP models will be introduced along with the need for development of similar models for Indian population. Effective and prompt medical countermeasures for decorporation of actinides in case of radiological/nuclear emergencies, i.e. mass contamination scenarios Challenges faced in development of biokinetic models for Indians are discussed. Decorporation treatment is most effective when administered shortly after contamination before the radionuclides become fixed in tissues. Current decorporation treatment options especially for actinides do not meet the challenge imposed by a mass casualty setting. An overview of factors that affect the efficacy of decorporation treatment and recent developments in this field are also covered in the present talk. (author)