by Allison Khoo, MS3, Baylor College of Medicine
Female representation in the US physician work force has grown tremendously in the last four decades, rising from 9.7% in 1970 to 32.4% in 2010.1 However, this dramatic rise is largely absent in the field of Interventional Radiology (IR) where only 2% of practicing interventional radiologists are women.2 Despite a modern era characterized by increasing gender equality, persistent barriers continue to hinder women from choosing IR. These barriers are multifaceted and include concerns over IR’s demanding call schedule and lack of female mentorship in the field. The most cited concern, however, is radiation safety, especially during pregnancy. One survey found that 1 out of 4 women who consider becoming an interventionalist do not pursue the career due to fears of fertility-related radiation risks.3 However, such concerns which discourage pursuing IR as a woman are unfounded. Interventionalists are not exposed to direct beams of radiation, but rather to scatter radiation and are protected by lead aprons. As medical students interested in the field of IR, we hope to encourage more women to pursue IR by addressing fertility-related radiation risks.
Fertility-related radiation risks can be subdivided into two periods: preconception and perinatal. The major concerns during the preconception period are sterility and gonadal cell mutagenesis while the major concerns during the perinatal period are embryotoxicity and birth defects. Sterility and Mutagenesis Risks are Minimal for Female Interventionalists Sterility is a deterministic effect of radiation exposure with a threshold dose of 2,000 mGy in premenopausal women.4 Gonadal cell mutagenesis, on the other hand, is a stochastic effect with risk increases with radiation dose.4 The 2001 United Nations Scientific Commission on Effects of Atomic Radiation (UNSCEAR) analyzed data from animal studies and survivors of the atomic bombings and found that the risk of mutagenesis increases by 0.43% per 1,000 mGy of exposure. Unfortunately, long term studies of female interventionalists have not yet been conducted. However, in contrast these doses, the average gonadal dose delivered by scatter radiation to an interventionalist is 0.01 mGy for a common IR procedure.4 Assuming maximum occupational exposure, it would take over 20 years for an interventional radiologist to receive a dose of 1,000 mGy. Given that the majority of American residents begin their training at age 26 and the average onset of menopause is 50 years, a female interventional radiologist would be just four years away from menopause before raising their risk of gonadal mutagenesis by 0.43%. While the lack of studies on this subject certainly cast doubt on some of these projections, our current level of knowledge suggests that the risk of sterility and mutagenesis are minimal for female interventionalists.
Perinatal Risks are Minimal for Female Interventionalists
Feared perinatal radiation toxicities including embryonic death, major malformations, growth retardation, severe mental disability, microcephaly, and decreased intelligence are all deterministic effects requiring a threshold dose of at least 60 mGy during the perinatal period.4 Marx et al conducted a prospective study of interventional radiologists wearing varying thicknesses of lead aprons. He calculated that the average dose to a pregnant interventional radiologist who works her entire pregnancy wearing double lead is 0.3Gy, well below the 60 mGy needed to cause any of the deterministic perinatal risks.5 Furthermore, a conservative model from the National Council on Radiation Protection and Measurements estimates that for a fetus exposed to 0.5mGy in utero, the probability of live birth without malformation or cancer is reduced from 95.930 to 95.928 – almost negligible.5
Women in Interventional Radiology
While preconception and perinatal risks of radiation certainly exist, their dangers to potential female interventional radiologists are exaggerated based on our current understanding. Upon attending the 2015 Society of Interventional Radiology conference, Dr. Natosha Monfore stated, “I was shocked at how few women are interventional radiologists. I listened to many different speakers throughout the conference and even attended the Women in IR luncheon only to realize there is not a fully sanctioned group for Women in IR.” Dr. Monfore has gone on to create such a group in an effort to bring female mentorship to a field in great need of it. It is our hope that with increased female leadership, mentorship, and education, we can make interventional radiology more open for women and attract great talent to the field.
1 AAMC Physician Specialty Data Book. (2012).
2 Sunshine, J. H., Lewis, R. S. & Bhargavan, M. A portrait of interventional radiologists in the United States. AJR. American journal of roentgenology 185, 1103-1112, doi:10.2214/AJR.05.0237 (2005).
3 Poppas, A. et al. Survey results: a decade of change in professional life in cardiology: a 2008 report of the ACC women in cardiology council. Journal of the American College of Cardiology 52, 2215-2226, doi:10.1016/j.jacc.2008.09.008 (2008).
4 Vu, C. T. & Elder, D. H. Pregnancy and the working interventional radiologist. Seminars in interventional radiology 30, 403-407, doi:10.1055/s-0033-1359735 (2013).
5 Marx, M. V., Niklason, L. & Mauger, E. A. Occupational radiation exposure to interventional radiologists: a prospective study. Journal of vascular and interventional radiology : JVIR 3, 597-606 (1992).