Personal monitoring of pregnant staff in diagnostic radiology

Abstract

In order to protect pregnant staff from the hazards of ionising radiation, additional controls are implemented. The International Commission on Radiological Protection have recently recommended that the fetus should be protected by the application of a supplementary dose limit of 2 mSv to the surface of the abdomen for the remainder of the pregnancy, once it has been declared. An experimental investigation was performed to discover the relationship between radiation monitor reading and equivalent dose to the uterus in diagnostic radiology. Tissue equivalent phantoms were used to simulate irradiation conditions typical of those in fluoroscopy. Scattered radiation distributions were produced using primary X-ray beams generated at three tube potentials (70, 90 and 110 kVp) for both overcouch tube and undercouch tube geometries. A further experiment was performed in which the tissue equivalent phantom was irradiated with primary radiation whilst being shielded by a protective apron equivalent to 0.25 mm and 0.33 mm lead. It may be deduced from the results of this investigation that, in the main, during fluoroscopy the application of a 2 mSv dose limit will limit the fetal dose to less than 1 mSv. Finally, a review is presented of those fluoroscopy procedures in which the supplementary dose-limit to the surface of the abdomen may be exceeded.