It is known that madical applications using ionising radiation are wide spread and still increasing. Phusicians, technicians, nurses and others constitute the largest group of workers occupationally exposed to man-made sources of radioation. Many hospital workers are consequently subjected to routine monitoring of professional radiation exposures in the university hospital, UZ Brussel, 600 out of 4000 staff mambers are daily monitored for external radiation exposures. . The most obvious applications of ionising radiation are diagnostic or therapeutic use of radionuclides in nuclear medicine and external radiation therapy or brachytherapy in radiotherapy departments. Other important applications also include various procedures in interventional radiology (IR), in vitro biomedical researchand radiopharmaceutical production around cyclotrons. Besides the fact that many of the staff members, involved in these appplications, are not measurably exposed, detailed studies were carried out at workplaces where routine dose monitoring encounters difficulties and for some applications where relatively high occupational exposures can be found, most of the studies are concentrated around nuclear medicine applications and IR. The contain assessments of both effective dose and doses at different parts ofthe body. the results contribute to better characterisation of the different workplaces in a way that critical applications can be identified.