[Ionizing radiation at low doses and cancer: epidemiological controversy]

The carcinogenic effects of ionizing radiation at high doses are un questionable. On the other hand, the deleterious exposure effects to low doses have not been totally proven, mainly due to methodological problems and difficulty in measuring reliable dose exposure. In this paper, some recent studies examining the effects of ionizing radiation in some occupational groups are reviewed and discussed. Also, the main areas of epidemiologic controversy are stressed. For future experiences, prospective, longitudinal studies with occupational cohorts, measuring radiation exposure with adequate registry and follow-up, are suggested.