Occupational exposure evaluation and radiation protection optimization in coronary angiography procedures

Abstract

Introduction The large number of coronary angiography procedures and inappropriate use of radiation protection equipment constitute a high occupational radiological risk for cardiologists generated by chronic exposure to low doses of radiation, in particular for parts of the body unprotected such as eyes and head. Materials and methods The eye lens dose was evaluated for seven cardiologists performing coronary angiography procedures over three months. The equivalent dose to the eye lens, Hp (3), was calculated from the equivalent dose to the skin, Hp (0.07), measured by an active dosimeter worn at the cardiologist's neck. The annual eye lens dose and the brain cancer risk were estimated. The correlation between the eye lens dose and the procedure parameters including the dose-area product, the fluoroscopy duration, and the number of fluography images was studied. Phantom-based measurements by a babyline 81 allowed to separate the contribution of the two modes, fluoroscopy and fluorography to the total dose and therefore, to propose another method of continuous lens dose monitoring. Finally, an optimization study was performed to reduce the eye lens dose and consequently the brain cancer risk. Results Two cardiologists have exceeded the annual lens dose limit (28mSv, 22mSv). A good correlation was found between Hp (3) and the fluoroscopy duration (R² = 0.89). The measurements showed that most of the exposure was in fluoroscopic mode (89%). The optimization study reduced the annual eye lens dose to 2.9 mSv and 2.3 mSv, respectively, for these two cardiologists. Thus, this decreased the brain cancer risk by a factor of ten. Conclusion The high eye lens annual doses recorded in this study are due to non-compliance with radiation protection rules. The proposed optimization process reduced the eye lens dose and the risk of brain cancer, at least, by a factor of ten.