Protection measures in roentgen diagnostics with reference to doses inducing mutations

The discovery by MULLER of an increased mutation rate in the Drosophita (fruit fly) after exposure to roentgen irradiation and the 6 to 7 times greater sensitivity of mammalians (mice) found byRms~~~, has aroused important questions in roentgen diagnostics: 1. What should be considered the maximum permissible dose to the gonads, remembering that the effect on the gonads is strongly cumulative and unaffected by any fractioning of the dose? 2. How great is the dose to the testicles and ovaries in diagnostic procedures? 3. How may the dose be diminished in a given diagnostic procedure? 1. Permissible dose. Sensitivity to this kind of damage varies in different species. The sensitivity in man is as yet unknown. If the results found after irradiation of mice with 80 r per generation are applicable to man, we shall obtain by this dose a doubling of the spontaneous mutation rate, raising the robability of genetic death from one in five to MULLER has found it advisable, as a provisional measure, to limit the dose to about 20 r per capita beforc: reproduction, antenatal life included. He also points out that a higher dose in a small group, e. 9. radiologic personnel, will not much affect the total injury to the population. In routine examinations the radiation to the gonads should be kept at the lowest possible level. One may perhaps make an exceptih in a few emergency cases. two in five individua P s.