[en] A brief description of the main operations performed in the Radioisotope Production Facility at IPEN-CNEN/SP is presented. This facility is provided with hot cells which must be periodically replaced due to deterioration by reagent processing and hard treatment to which they are submitted. When the lifetime of these hot cells are at their limit, leaking of airborne materials arises bringing forth incorporation by workers. As a safe control, a series of procedures have been implemented in a program of internal monitoring by urine sampling and external monitoring by film badge. From this program it became possible to evaluate the radiation dose received by workers. The results obtained within the last 10 years where analyzed against the lifetime of the hot cells and studies were made to verify possible explicit or implicit relations between doses and the natural stress of these hot cells. In the distribution of the effective dose equivalent among 304 workers submitted for individual monitoring of internal exposure by urine samples, some significant exposures higher than 4.5 mSv. The sum of effective doses and doses from external exposures can lead to levels close to regulatory limits. The internal effective dose equivalent is small when compared with whole body external dose equivalent, however it is not negligible