33 “one radionuclide to another. Factors that may be of importance in de- termining the quantity (measured in ecurtes or in fractions of a cure) of a particular radionuclide that would result in serious injury if taken into the body include: the chemical element of which the material is a nuclide; the chemical form of the substance; the radioactive half-life of the nuclide; the average energy emitted per disintegration; the manner in which the substance is introduced into the body; and, especially for materials of relatively short half-lives, the interval of time over which the substance is introduced into the body. Factors enumerated above determine the retention and distribution of a given radionuclide in the body, total radiation doses to various organs and tissues, and rates at which these doses occur. Because different individuals respond differently to dangerous doses of radiation, as they do to other severe biclogical stresses, one cannot state with confidence the minimum quantity of a given radionuclide that might be required to kill a particular individual. Some of these considerations are illustrated by the following examples: Radiation doses resulting from the inhalation of a curie of tritium as a gas (i. e., as +H, or 35m) would be too small to produce observable effects. A curie of tritium oxide (FH,0 or 3HHO) would result in a whole body radiation dose of about 200 rads. Even if this amount were inhaled within a short period of time, consequent irradiation of body tissues would be spread over a period of weeks. <A person exposed at this level probably would experience no symptoms