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From the event to medical treatment

Decorporation following contamination (or internal exposure)

​Internal exposure continues as long as the radioactive substance has not been eliminated naturally by the body, or through radioactive decay. Treatment with a decorporating agent is aimed at promoting natural elimination.

Published on 18 March 2015

The objective is to reduce the load of radionuclides incorporated in the body, in order to reduce the radiation dose and thus avoid the onset of health effects. The administration of a therapy must begin as soon as possible following contamination, to maximize its efficiency.

Two therapeutic principles exist for decorporation:

  • an increase in spontaneous excretion of the radioactive contaminant after its absorption (in the case of DTPA or potassium iodide),
  • a decrease in its absorption in the body (in the case of Prussian blue).

Ongoing research aims to optimize the protocols of existing treatments, so as to identify treatments that are easier to administer or that are more effective. Others means would be necessary for radionuclides or the chemical forms of certain radionuclides without treatment.

Adults and adolescents : 0,5 g per dose, not to exceed 1g/d 
Children< 12 ans : 14 mg/kg, not to exceed 0,5 g/d
The treatment duration depends on the results from radiotoxicological analyses.
In France, the calcium form of DTPA (Ca-DTPA), an injectable solution, has its marketing authorization since 2008. Its indication is for local use in the treatment of wounds contaminated by the radionuclides plutonium, americium, curium, iron, and cobalt, or for intravenous use in the case of other penetration paths by the same radionuclides. Ca-DTPA, manufactured by the Pharmacie Centrale des Armées (PCA), is an antidote that acts by chelation. It exchanges calcium ions against metal ions (which include radionuclide contaminants) by forming stable complexes, which will be eliminated primarily in the urine.

In France, stable iodine tablets (in the form of potassium iodide, KI) have their marketing authorization since 1997, and are manufactured by PCA. Stable iodine saturates the thyroid gland, thereby preventing inhaled or ingested radioactive iodine from attaching to it. Radioactive iodine is then eliminated primarily in the urine. In the case of a contamination risk by radioactive iodine, the size of the stable iodine dose depends on the person’s age and physiological state (i.e. pregnant women).

  • WHO recommended single dosage of stable iodine according to age group (Word Health Organization)
​Age category
Iodine dose
(en mg)​
Number of KI tablets(65 mg)​
Children over 12 y and adults​100​2
Pregnant women​100​2
Children 3-12 years​50​1
​1 month - 3 years​25​0,5
​Birth - 1 month​12,5​0,25