Radiotoxicology of Tritium and 14C Compounds

Abstract

Maximum permissible annual intakes to blood of several tritiated compounds, namely, water, folic acid, corticosteroids, sex-hormones and thymidine, have been estimated on the basis of average doses by received organs and tissues and from experiments on rats. The values range from 10 mCi for tritiated thymidine and folic acid to 1 or 2 Ci for tritiated corticosteroids. Values for corresponding 14C labelled compounds will, in general, be lower because of the higher energies of the 14C beta-particles. Dosimetry in cells is considered, particularly in relation to tritium and 14C labelled thymidine. Questions concerning the importance of inhomogeneity of absorbed energy in microscopic volumes are discussed in relation to the use of average dose as the basis for settine maximum permissible levels of dose and intakes of " " tritium and 14C labelled compounds.

Cerebral Blood Flow with the Continuous Infusion of Oxygen-15-Labeled Water

“…The cumulated activity for the kth target organ is A B W k F k A k = W B F B where W k refers to mass and F k refers to the frac tional water space (Vennart, 1969) of the source tissue k and W B and F B refer to mass and fractional water space of the whole body, respectively. This expression assumes that 150 is distributed ac cording to water volume, an assumption that is useful for the calculation of radiation dose.…”

Information for establishing bioassay measurements and evaluations of tritium exposure

“…Shaw, in a private communication quoted in Vennart (Ref. 54, p. 429), has indicated that injections of the tritiated sex hormones oestradiol and testosterone result in smaller doses in all organs of the rats than those from equal injections of tritiated water. There is also an absence of appreciable hematologic changes in patients after intravenous doses of 10 curies of tritiated tetrasodium 2-methyl-l,4-naphthaquinol diphosphate (Refs.…”