After exposure of mice and rats to ultraviolet radiation, the yield of cutaneous carcinomas regularly depends on radiation dose and dose distribution. In man, according to comparison of radiation climate with cancer frequency and based on distribution studies of skin exposed to light, the rules are supposed to be of the same kind. Thereby, the latent period is additionally influenced by genetically determined radiosensitivity (melanin content; DNA repair and by the action of syncarcinogenic and concarcinogenic factors. The resulting correlations between UV-light absorption and initiation of cutaneous carcinomas are tight in spinocellular carcinoma, distinct in basaloma, and questionable in melanoma. By converting the estimated UV-radiation doses into "Biological Units", it is possible to determine the risk of cutaneous carcinoma induced by artificial radiation sources as compared with the risk by radiation from sun and sky.
