Pregnant MRTs notify their employers of their pregnancy and take steps to minimize their exposure to radiation
Radiation during pregnancy
- Avoiding unnecessary exposure to the developing fetus or embryo is essential due to the radiosensitivity of rapidly dividing cells1.
- Exposure of the unborn fetus to ionizing radiation increases the risk of somatic effects as well as genetic effects that could be passed to subsequent generations1.
- Federal and provincial regulations exist to address occupational exposure to radiation, and include considerations for pregnant workers.
- MRTs should be familiar with the regulations that apply to their jurisdictions and facility
Ionizing radiation dose limits
- An MRT can continue working during pregnancy, but must take measures to keep effective fetal dose below prescribed limits2.
- The whole body effective dose limit for pregnant MRTs (both radiation and nuclear energy workers) in Canada is 4 mSv, from the time that pregnancy is declared until the end of term1,3.
- After an MRT has declared her pregnancy, the effective dose to the surface of the abdomen should not exceed 2 mSv for the remainder of the pregnancy.
- There are relevant provincial regulations in some jurisdictions, as well4-9.
- Additional radiation monitoring equipment may be provided, depending on the facility.
- Health Canada recommends dosimeters are monitored closely and checked for radiation doses every 2 weeks10.
- The recommended dose limit applies to the fetal dose and it is not directly comparable to the dose measured on a personal dosimeter2.
- A personal dosimeter may overestimate fetal dose by a factor of 10 or more
- If the dosimeter has been worn outside a lead apron, the measured dose is likely to be about 100 times higher than the fetal dose
- In radiation therapy, doses are not likely to exceed 25% of the personal dosimeter measurement
Considerations for radiologic technology
- An MRT who becomes aware that she is pregnant must notify her employer1.
- Personal protective equipment is used1.
- There are no limitations to the performance of diagnostic x-ray procedures, including the use of mobile units1.
- There are no limitations to the performance of interventional procedures including the use of fluoroscopy1.
Considerations for nuclear medicine
- An MRT who becomes aware that she is pregnant must notify her employer in writing, as well as the Radiation Safety Officer3.
- Personal protective equipment is used1.
- Performance of procedures that result in high exposure to radiation (e.g., therapeutic procedures, preparation of radiopharmaceuticals) is considered in the context of total fetal dose limit for the pregnancy.
Considerations for radiation therapy
- An MRT who becomes aware that she is pregnant must notify her employer3.
- Personal protective equipment is used1.
- Radiation therapists are restricted from handling brachytherapy sources and may be restricted in treating patients on a Cobalt unit.
- Radiation therapists may perform simulations, linear accelerator administered external beam radiation therapy and image guidance.
Considerations for magnetic resonance
- An MRT who becomes aware that she is pregnant must notify her employer.
- Pregnant MRI technologists are permitted to work in and around the MRI environment throughout all stages of their pregnancy11-12.
- MRI technologists are advised not to remain in the scanner room during actual data acquisition or scanning11.
References
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Health Canada. Safety Code 35: Safety Procedures for the Installation, Use and Control of X-ray Equipment in Large Medical Radiological Facilities. Available from: http://www.hc-sc.gc.ca/ewh-semt/pubs/radiation/safety-code_35-securite/index-eng.php. [Accessed 12 Dec 2019]
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International Atomic Energy Agency. Radiation Protection of Patients. Pregnancy and Radiation Protection in Diagnostic Radiology. Available from: https://rpop.iaea.org/RPOP/RPoP/Content/SpecialGroups/1_PregnantWomen/Pregnancyandradiology.htm. [Accessed 27 Mar 2013]
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Government of Canada. Justice Laws Website. Radiation Protection Regulations (SOR/2000-203). Available from: http://laws.justice.gc.ca/PDF/SOR-2000-203.pdf. [Accessed 29 Jan 2018]
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Health Canada. Environmental and Workplace Health. Dose Limits. Available from: https://www.canada.ca/en/health-canada/services/environmental-workplace-health/occupational-health-safety/occupational-radiation/national-dosimetry-services/resource-centre/dose-limits.html. [Accessed 27 Apr 2018]
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Government of British Columbia. Workers Compensation Act. Occupational Health and Safety Regulation. Available from: http://www.bclaws.ca/EPLibraries/bclaws_new/document/ID/freeside/296_97_05. [Accessed 4 Oct 2013]
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Government of Alberta. Radiation Protection Act. Radiation Protection Regulation. Available from: http://www.qp.alberta.ca/1266.cfm?page=2003_182.cfm&leg_type=Regs&isbncln=0779731042. [Accessed 4 Oct 2013]
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Government of Saskatchewan. The Radiation Health and Safety Regulations, 2005. Available from: http://www.qp.gov.sk.ca/documents/English/Regulations/Regulations/R1-1r2.pdf. [Accessed 4 Oct 2013]
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Government of Manitoba. Manitoba Workplace Safety and Health Act and Regulation. 2016. Available from: https://www.gov.mb.ca/labour/safety/pdf/1_2016_wsh_ar_oc.pdf. [Accessed 30 Apr 2018]
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Government of Ontario. Occupational Health and Safety Act (R.R.O. 1990, Regulation 861: X-ray Safety). Available from: http://www.e-laws.gov.on.ca/html/regs/english/elaws_regs_900861_e.htm. [Accessed 30 Apr 2018]
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Health Canada. Healthy Living: It’s Your Health. Occupational Exposure to Radiation. Available from: https://www.canada.ca/en/health-canada/services/healthy-living/your-health/environment/occupational-exposure-radiation.html. [Accessed 27 Apr 2018]
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Kanal E, Barkovich J, Bell C, et al. ACR Guidance Document on MR Safe Practices: 2013. J Magn Reson Imaging 2013;37:501-530.
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Shellock FG. Reference Manual for Magnetic Resonance Safety, Implants, and Devices. 2012 ed. Los Angeles, CA: Biomedical Research Publishing Group; 2012.