Radiation Safety for Women in Cardiology: Myths and Important Messages

Is it safe to continue to work in the coronary catheterization laboratory while pregnant?

The simple answer to this question is Yes, it is safe to continue to work in the coronary catheterization laboratory while pregnant. However, we need to acknowledge that evaluating the true risk to healthcare workers when pregnant can be challenging and is important. The amount of extra radiation exposure to the fetus of a pregnant interventional cardiologist or trainee is often overestimated, and background radiation exposure is often underestimated^[2,4,8,21] [Figure 1] (Data and image adapted from Gahan et al.^[8] and from Sahni et al.^[21]). The average total occupational radiation dose to the fetus/uterus of a working pregnant interventional cardiologist is estimated to be 0.09mSv over her entire pregnancy.^[8,22] The average background radiation exposure is 2.4mSv^[21] worldwide, but varies geographically. Therefore, the incremental increase in radiation exposure from occupational radiation under leads is actually very small.

Legal radiation dose limits are intended to decrease or mitigate risk. There are no differences between the effects caused by natural radiation or radiation made by people which is artificially generated by industry or for medical use. The key to understanding radiation risk is understanding the amount of extra radiation (above the background daily exposure we all face) generated by working in occupational radiation.

While the developing fetus is highly sensitive to radiation, particularly in the first trimester, the scale of exposure from occupational exposure in the cardiac catheterization laboratory is a tiny fraction of documented thresholds for fetal injury.^[4,8,21,23] If we keep the additional under lead dose to ≤1 milliSv, we change the background risk of childhood cancer or congenital malformation from 4.070% to 4.078%; if it is ≤0.5 mSv (which research reports suggest is most likely), we change background risk from 4.070% to 4.072%.^[4,8,22,24] Radiation exposure effects [Table 1] require logarithmically higher doses of exposure and/or long durations of exposure than reported under-lead radiation doses to fellows or interventionalists, or to other healthcare workers in the catheterization laboratory^[4] [Figure 1 and Table 1]. In terms of absolute risk, the probability of congenital malformation or cancer in a fetus of a pregnant interventional cardiologist or fellow increases a very small amount.

Is it legal to continue to work in the coronary catheterization laboratory while pregnant?

Internationally, legal radiation safety guidelines with statement regarding pregnancy are available, but vary country to country.^[4] Table 2 summarizes their recommendation for pregnant workers. Most (but not all) countries allow pregnant workers to continue in cardiac catheterization laboratories with appropriate lead protection and monitoring.^[25] In Europe, recent updated definitions of safe dose limits and standards for fetal exposure have been published from the European directive,^[25] resulting in repeal or removal of previously more conservative policies or directives. Internationally recommended under-lead thresholds for the entire pregnancy are between 1 and 5 mSv.^[4] These thresholds are very conservative values and are well below the 100 mSv threshold for fetal injury.^[22]

The recently published European Association of Percutaneous Cardiovascular Interventions (EAPCI) statement on Radiation Exposure and Safety in Catheterization Laboratories for Health-care Professionals during Pregnancy reported global data from practice and found pregnant^[25] interventional cardiologists monitoring their under-lead thresholds report measured under-lead doses well below these legal thresholds.^[23,26-31]

How can we monitor and limit any risk? Safe practices that minimize radiation exposure

Occupational radiation management and risk mitigation are essential for all interventional cardiologists. All workers should aim to keep exposure as low as reasonably possible (ALARA). Research demonstrates 50–86% of female cardiologists and interventional cardiologists work in coronary catheterization laboratories with occupational radiation during pregnancy.^[30,31] Critical organogenesis (weeks 2–8) is a particularly important time to limit radiation exposure and ensure good radiation safety practices, while timing of notification and confidentiality are also important issues to navigate in the first trimester.

Critical practices to minimize exposure should be adopted, including dosimeter use, monitoring, and well-maintained protective shielding. A separate under-lead fetal radiation counter or dosimeter badge with monthly monitoring is highly recommended and often mandated. Case by case dose monitoring can also be extremely reassuring and help to guide ALARA practices, and as documented in the EAPCI consensus statement, are often used. Safe fluoroscopy practices are essential, these include using fluoroscopy-store technology (last hold imaging) to minimize unnecessary cineangiography, minimizing radiation “on time,” choosing appropriate angle selection with lower radiation doses, scatter minimization with low image intensifier position, and minimization of magnification and frame rate.^[8,28,29] Weightless lead and robotics percutaneous coronary intervention tools, where available, can provide alternative potential options for radiation protection. Mobile Perspex or lead shields should be available in all labs and careful positioning close to the operator should be used. Old equipment should be regularly updated as doses delivered by aging equipment increase dose and risk. Some countries such as Australia embed equipment update mandates into funding policy, to facilitate safe practice. There is an ethical imperative for institutions, managers, funding bodies and governments to take responsibility for equipment replacement, servicing, and updates to provide appropriate protection for all occupational radiation safety workers. All trainees should receive radiation safety training and part of advanced training and interventional fellowships, so they understand the importance of time, distance, and shielding to reduce radiation exposure.^[4,8,20,22] Trainees should be directed to radiation safety courses and resources within hospitals which should include overt statements about pregnancy risk that are accurate and evidence based. Online resources such as the Women as One radiation safety initiative and tutorial,^[20] society for cardiovascular angiography and interventions (SCAI) consensus document,^[3] and EAPCI statement^[4] ensure equitable access to accurate information regardless of worksite.

Evidence-based thresholds for radiation exposure are important; however, guidance from regulatory bodies vary worldwide, so do regulations and practices.^[4] Safety equipment including well-maintained lead gowns and shields, radiation counters to quantify risk, and nationally endorsed guidelines for safe exposure to radiation are all essential tools to mitigate risk. When we use and are aware of ALARA techniques to minimize exposure, risks to the fetus remain extremely low in appropriately shielded and monitored workers.^[3,4,21,24]

For healthcare workers, themselves the risk of malignancy from poorly shielded sites, including the head and in some cases the breast, must also be considered and avoided. Lead gowns with arm and breast shields should be provided to workers. Postpartum, there is guidance suggesting that lactation and breastfeeding are not unsafe during ionizing radiation exposure^[4,31] and interventionalists are advised to wear appropriately-sized upper torso lead aprons, and ideally leads with a lead sleeve to shield breasts, to provide additional protection to upper outer quadrant of the breast. Lead gowns should also be regularly screened for damage and stored carefully to limit the risk of damage.

Great leaders lead with evidence-based practice, and a goal of giving all of their staff a sense of belonging, and a career they love, without giving up on the joy of having a family. National societies should also provide readily accessible links to accurate educational materials, relevant policies, and legal requirements.

This editorial is written collectively by interventional cardiologists, ethicists, and leaders from nine different countries, most of us are also mothers. We have navigated the demands of training, on-call duties, demanding emergency work, and academic medicine; and worked safely with occupational radiation, it can safely be done. We have also done it so the women that follow in our footsteps have the role models they need.