(5) The worst years scem to be 13953 an? i957. “t) Many Grah chis.i or have received thyrcid Joses of several reds. (ad) The St. (e) These ccse estivates need to be improved. Gearge exposures were sizable. data shouid be releascd; air beta concentrations Tor 1951, i952, In particular, field gamma shculd be nace available 1353 and 1955; and if not contrary to the interests of national security, xiieten yields for the July 1962 tests are needed. Perhaps a future “im ident’ will provide the needed calibration check! PREDICTED TH.CID CANCERS I realize that any attempt to predict an increase in cancer due to low doses of radiation is subject to great inaccuracy and criticism. This is especially true when the dose estimates are so very approximate. There fore, it sheuld be understood that the following estimates were made pri- marily to indicate whether or not an effort to search for increased thyroid cancers would be justified. Archer anc 5 impson 1) have tabulated 10 thyroid cancers in 2253 children x-irradiated as infants for “an enlarged thymus" with an average dose of 225 rads, and an average follow-up time of 14.5 years. we have no . i at later : At present tion en how many additional thyroid cancers will develop na m | 38.5 years. They have calculated that 0.05 dencere should have been expected normally in this iyperiod. Assuming a linear relation between dose and incidence’, there should be l case per 50,000 read-children. el me * To my satisfaction this relation has neither been proved or disproved adaquately for thyroid cancer.