Three decades of occupational individual monitoring at the University of São Paulo.

As the ionizing radiation to which workers are exposed is related to possible harmful biological effect, its dose evaluation gains relevance. Although the effects of low doses are still controversial, the radiation protection authorities assume that any dose of ionizing radiation is potentially harmful to the human health and adopt the linear non-threshold model for the dose-effect relation. The Dosimetry Laboratory of the Institute of Physics of the University of São Paulo performs the external individual monitoring of workers exposed to X- and gamma-rays since 1981, with the technique of thermoluminescence. Currently, ~500 badges are provided to the university professionals mostly working in research laboratories and hospitals. Data of individual annual dose equivalent collected from 1995 to 2015 and the performance of the monitoring service are presented in this paper.