ESR News March 2015
Radiation exposure of pregnant workers during diagnostic and interventional procedures
John Damilakis, Professor of Medical Physics
It is known that the use of diagnostic X-ray examinations grew rapidly during the last decade. It has also been well documented that both the use and complexity of fluoroscopically-guided interventional procedures are increasing worldwide (1). This increase in medical imaging has been accompanied by concerns about the increasing levels of radiation to which radiologists, interventionalists and support personnel are being exposed. There are many misconceptions about pregnant personnel working in diagnostic and interventional radiology, and the conceptus radiation doses and risks associated with occupational radiation exposure.
Special recommendations and guidelines apply after a pregnant employee declares her pregnancy (2). The new European Basic Safety Standards state that
‘1. Member States shall ensure that the protection of the unborn child is comparable with that provided for members of the public. As soon as a pregnant worker informs the undertaking or, in the case of an outside worker, the employer, of the pregnancy, in accordance with national legislation the undertaking, and the employer, shall ensure that the employment conditions for the pregnant worker are such that the equivalent dose to the unborn child is as low as reasonably achievable and unlikely to exceed 1 mSv during at least the remainder of the pregnancy.
2. As soon as workers inform the undertaking, or in case of outside workers, the employer, that they are breastfeeding an infant, they shall not be employed in work involving a significant risk of intake of radionuclides or of bodily contamination’.
Radiation doses to occupationally exposed healthcare personnel from many fluoroscopy examinations and fluoroscopically-guided interventional procedures are high, and it is likely that in some cases, for a pregnant employee, the conceptus equivalent dose limit of 1 mSv can be approached or even exceeded. Early declaration of pregnancy is needed in view of the conceptus risks associated with radiation exposure.
After declaration of pregnancy, training of the pregnant worker and special radiation protection measures are needed to keep conceptus dose lower than the limit of 1 mSv during the remainder of the pregnancy. Conceptus dose anticipation and maximum workload determination is important for pregnant staff participating in fluoroscopy and fluoroscopically-guided interventional procedures. Personal dosimeters are of limited value because they can only provide the dose to the surface of the woman’s abdomen, retrospectively. Iso-dose maps of air-kerma doses normalised to dose area product (DAP) for projections and procedures commonly employed in the electrophysiological laboratory have been published (3). This information can be used to (a) anticipate conceptus dose from occupational exposure of pregnant staff during these fluoroscopically-guided procedures and (b) estimate the maximum workload allowed for each month of gestation period following pregnancy declaration. Information provided in the above publication is also useful for young female employees who are planning to become pregnant. These workers could take into consideration iso-dose maps and select the most suitable position that allows them to decrease radiation doses to the pelvic area as much as possible (3). Further studies are needed to provide similar data for pregnant workers participating in other fluoroscopically-guided procedures.
References
1. Miller DL. Overview of contemporary interventional fluoroscopy procedures. Health Physics 2008;95:638-44
2. Council of the European Union. (2013). Council Directive 2013/59/Euratom laying down basic safety standards for protection against the dangers arising from exposure to ionising radiation, and repealing Directives 89/618/Euratom, 90/641/Euratom, 96/29/Euratom, 97/43/Euratom and 2003/122/Euratom. Official Journal L-13 of 17.01.2014.
3. J. Damilakis et al. Anticipation of radiation dose to the conceptus from occupational exposure of pregnant staff during fluoroscopically guided electrophysiological procedures J Cardiovasc Electrophysiol 16:773-780, 2005.