Appendix 9 (continued) C. Data on Principle [Isotopes of Iodine Contributing to Thyroid Dose (From "Inhalation of Radioiodine from Fallout: Hazards and Countermeasures" by R. Colet37) E max’ MeV Relative abundance, % Range in tissue, um 50%~Dose radius,* un Iodine-131 Betas 0.246 2.2 0.332 10.6 0.606 0.807 1,000 86.4 0.8 150 2,100 310 375 Iodine-132 Betas 0.681 15 2,500 0.934 20 3,900 1.150 1.583 2.111 22 22 21 625 5,400 8,400 11,900 920 1,500 2,400 6,800 1,200 8,100 15,800 1,460 3,300 Teodine-133 Betas 0.49 1.34 7 93 Iodine-134 Betas 0.87 1.55 2.65 3.51 5 65 25 '5 Todine-135 Betas 0.40 1.00 35 40 1,300 4,300 195 690 1.43 25 7,300 1,300 *The 50%-dose radius is defined, for a point source in tissue, as the distance within which 50% of the dose, for that energy, is distributed. **Since this isotope with 53-min half-life is important only for about 6 hr, it was not considered in the Marshallese thyroid dose calculations. - 117 -