403 Pregnancy and the Working Interventional Radiologist Catherine T. Vu, MD1 DeirdreH.Elder,MS,CMLSO2 1 Department of Radiology, University of California Davis Medical Address for correspondence Catherine T. Vu, MD, University of Center, Sacramento, California California Davis Medical Center, 4860 Y Street, Suite #3100, 2 Department of Radiation Safety, University of Colorado Hospital, Sacramento, CA 95817 (e-mail: [email protected]). Aurora, Colorado Semin Intervent Radiol 2013;30:403–407 Abstract The prevalence of women radiologists has risen in the past decade, but this rise is not Keywords reflected in interventional radiology. Women are grossly underrepresented, and this ► interventional may be partly due to fear of radiation exposure, particularly during pregnancy. The radiology simple fact is radiation exposure is minimal and the concern regarding the health of the ► pregnancy developing fetus is unjustly aggrandized. Fully understanding the risks may help women ► radiation exposure to choose interventional radiology and practicing women interventionalists to stay ► radiation safety productive during their child-bearing years. To date, little has been published to guide ► occupational injury women who may become pregnant during their training and career. Objectives: Upon completion of this article, the reader will be choosing specialties such as family medicine, pediatrics, able to discuss the real risk of radiation to the pregnant and obstetrics and gynecology. This phenomenon has been working interventionalist and her fetus, and techniques to linked to the attraction of these specialties having the reduce radiation dose and work-related injuries. traditional “family-friendly” reputation, where women Accreditation: This activity has been planned and imple- can achieve the quintessential work–life balance. As wom- mented in accordance with the Essential Areas and Policies of en conventionally bear the childcare responsibility, they the Accreditation Council for Continuing Medical Education typically sacrifice career opportunities and limit their (ACCME) through the joint sponsorship of Tufts University career choices. School of Medicine (TUSM) and Thieme Medical Publishers, In this era where modern women struggle less with gender New York. TUSM is accredited by the ACCME to provide equality, barriers still exist that might hinder women from continuing medical education for physicians. choosing IR. Aside from the possible work–life disproportion Credit: Tufts University School of Medicine designates this and salary inequities, there is a paucity of female mentors and journal-based CME activity for a maximum of 1AMAPRA a misbelief that women should work part time to attend to Category 1 Credit™. Physicians should claim only the credit childcare needs. Until more women enter IR and take on commensurate with the extent of their participation in the leadership positions, women will likely continue to be under activity. represented. Some women may also be dissuaded by the “old boy’sclub” mentality. But the challenges of the proverbial The latest statistics on the number of women physicians male-dominated practices and egos described in surgical represents a milestone in history. In the 21st century, more subspecialties are not as pervasive in IR. This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited. than 30% of U.S. physicians are female. Between 1980 and Women were among the pioneers of IR during its forma- 2010, the number of female physicians grew by 447%.1 The tive years, from the late 1960s to the mid-1980s. Arina van prevalence of women radiologists has also grown; in 2012, Breda was one of the first to perform catheter-directed women represent 22% of all radiologists, a rise from 16% in thrombolysis and publish her results of using local streptoki- 2000.2 This rise, however, is not reflected in interventional nase infusions in acute thrombosis.4 Since the foundation of radiology (IR), where women represent merely 2% of all this field is rooted in innovation, women stand on equal interventional radiologists.3 The number of women choos- ground where creative minds are valued and novel treat- ing a career in IR trails far behind the influx of women ments are embraced. Gender disclosure has never been Issue Theme Women’sHealthand Copyright © 2013 by Thieme Medical DOI http://dx.doi.org/ Interventional Radiology; Guest Editors, Publishers, Inc., 333 Seventh Avenue, 10.1055/s-0033-1359735. Kimi L. Kondo, DO and Laura Findeiss, New York, NY 10001, USA. ISSN 0739-9529. MD, FSIR Tel: +1(212) 584-4662. 404 Pregnancy and the Working Interventional Radiologist Vu, Elder compulsory for Society of Interventional Radiology member- difficult to understand. Rad and Gray (Gy) are used to express ship, but women remain under-represented. absorbed dose, which is the concentration of energy deposited One of the concerns is radiation exposure and its effect on in a material or the energy per unit mass. The conventional childbearing. During pregnancy, working interventionalists unit for absorbed energy is the rad, which is 100 ergs of are also at risk for occupational injuries from weight gain that energy per gram of the given material. The international become aggravated with prolonged standing. Understanding system of units (SI) for absorbed energy is the Gy, which is one radiation exposure and radiation safety frequently gets lost in joule per kilogram. While many professional organizations the physics. This article will simplify this aspect of radiation favor discarding the conventional units in favor of SI units, physics and allay the unfounded and perceived risks. It will regulations and dose reports are still often presented in the also provide recommendations to reduce radiation dose and conventional units. Additionally, X-ray tube outputs are often work-related injuries. given as the Air Kerma in Gy or mGy. Rem and Sievert (Sv) are used to express dose equivalent, Radiation Exposure which accounts for differences in biological effectiveness of different types of radiation by incorporating a quality con- There are several different types and sources of radiation. version factor. For X-rays and other photons, the quality factor Interventional radiologists are primarily exposed to photons is one, so a rad of absorbed dose is equivalent to a rem of dose (electromagnetic radiation) from X-ray tubes. Exposure to equivalent. For X-rays, a Gy of absorbed dose delivers a Sv of other types of radiation is beyond the scope of this paper. dose equivalent. Risks associated with radiation fall into two categories, Effective dose is used in radiation protection to equate the stochastic risks and deterministic risks. Stochastic risks are stochastic risks due to a nonuniform exposure to the risks those for which the probability of the effect increases with associated with a uniform whole body exposure. Plainly dose. Stochastic effects may occur with higher doses and longer speaking, effective dose is used to estimate cancer risk and exposures, and risks include genetic mutations and cancer. the unit used is rem or Sv. Deterministic risks, also referred to as nonstochastic risks, occur The unit conversions for rad, mGy, mrem, and mSv are as above a threshold dose. Therefore, if the threshold is not follows: reached, the effect is not observed. The severity of determin- 100 rad ¼ 1Gyor1,000mGy istic effects increases with doses above the threshold. 1 Gy (or 1 mGy) absorbed photon dose ¼ 1Sv(or1mSv) Radiation exposure is strictly monitored for all radiation dose equivalent workers. Radiation doses are monitored monthly for inter- 1mrem¼ 0.01 mSv or 100 mrem ¼ 1mSv ventional radiologists with a dosimeter worn outside the lead To keep this article relatively simple, mGy will be used to on their thyroid collar. Some facilities issue a second dosime- express absorbed dose in tissue and mrem will be used to ter to be worn under the lead apron. In the United States, the measure occupational dose. declaration of pregnancy is strictly voluntary and when a pregnant worker declares her pregnancy she is issued a fetal Radiation Risks dosimeter to be worn at the level of the abdomen under any lead protective garments. The monthly dose readings are Risks to the embryo or fetus are divided into preconception monitored by the radiation safety officer to verify that the risks and perinatal risks. The risks associated with precon- regulatory fetal dose limits are not exceeded. The National ception exposures are genetic mutations leading to heredi- Council for Radiation Protection (NCRP) has published rec- tary effects and sterility. The United Nations Scientific ommended dose limits based on a careful review of the Commission on Effects of Atomic Radiation (UNSCEAR) has scientific literature and most states have adopted these analyzed the scientific data from animal studies and survivors recommendations in their regulations. The radiation dose of the atomic bombings at Hiroshima and Nagasaki. The limits are intended to prevent deterministic effects and UNSCEAR 2001 report estimates the total risk of hereditary minimize the risk of stochastic effects. The annual deep effects in humans, which increases by 0.41 to 0.46% per 1,000 This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited. dose equivalent limit for occupational exposure is 5,000 mGy of exposure.6,7 It would take 20 years of maximum mrem. The fetal dose limit is 500 mrem over the duration occupational exposure to reach a dose of 1,000 mGy. Sterility of the pregnancy, or 50 mrem per month.5 What does this is a deterministic effect for which the threshold dose in mean in lay terminology? An electronic search using the key women ranges from 12 Gy or 12,000 mGy before puberty phrases “radiation exposure” and “pregnancy” can produce to 2 Gy or 2,000 mGy in premenopausal women.6 These doses over 100,000 results. Open any one of these articles and one are well above the typical lifetime exposure in interventional may find radiation doses and exposures expressed in mrem, procedures.