Pregnant Radiographer: Fetal Dose and Reasonable Adjustments
A 32-year-old therapeutic radiographer at a busy cancer centre tells her line manager she is 8 weeks pregnant. She works a mixed role: two days on a 6 MV/10 MV linac treating up to 22 patients per day (including IMRT, VMAT and SBRT), one day in CT simulation, and one day in the planning dosimetry office. Her whole-body TLD badge for the previous three months records 1.1 mSv; her collar badge records 1.4 mSv. The department has a written policy that declares pregnancy voluntarily so that dose to the fetus can be monitored with an additional badge at the waist. The manager is supportive but says staffing is tight and asks whether she can continue her current duties with the abdominal badge. She has had no morning sickness. The department uses 6 MV and 10 MV photons, with occasional 15 MV for deep pelvic cases; there is no sealed-source work.
1. What fetal dose limit applies, and how would you assess her likely fetal dose from the badge records?
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Reasoning
In the UK, once a pregnancy is declared, the legal dose limit for the fetus is 1 mSv for the remainder of the pregnancy under IRR17. Many departments adopt a stricter local ALARA target of 0.5 mSv. The limit applies to the fetus, not to the mother's whole-body badge, so a dedicated waist badge is required and should be worn under any lead apron if one is used.
Her recorded badges are historical and do not measure fetal dose. The whole-body badge of 1.1 mSv over three months and collar badge of 1.4 mSv suggest low occupational exposure, but the collar badge overestimates fetal dose and the whole-body badge may be worn at chest or waist level depending on local practice. A reasonable conservative estimate is that fetal dose is lower than the waist badge and substantially lower than the collar badge for external photon exposure. With a waist badge, the fetal dose can be estimated from the waist reading with a correction for shielding and geometry; if no waist badge has been worn, the whole-body badge is the more conservative available surrogate.
Judgement: her historical dose is well below 1 mSv, but the declared pregnancy starts a new monitoring period. Issue a waist badge immediately, record the declaration date, monitor monthly, and review her duties prospectively against the 0.5 mSv local target. Do not tell her she must stop work solely because she is pregnant.
2. What reasonable adjustments and risk assessment would you put in place, and how would you decide whether she can remain on the treatment unit?
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Reasoning
The risk assessment should be individual and proportionate. The main external exposures are scatter from patients, leakage, and workload from high-MU techniques. At 6–10 MV, photon scatter is the dominant concern; 15 MV can produce minor neutron exposure, so deep pelvic 15 MV cases should be avoided where practical. SBRT and VMAT have high monitor units and longer beam-on time, so they warrant particular caution but are not automatically prohibited if her badge remains low.
Reasonable adjustments could include:
- Rotating her away from the busiest SBRT/VMAT lists and 15 MV cases, or limiting the number of high-MU patients per session.
- Prioritizing CT simulation and planning-office duties, while retaining some treatment work if her waist badge stays well below the local target.
- Avoiding emergency on-call and long shifts; allowing rest breaks and access to facilities.
- Reviewing manual handling, infection risk, and latex exposure.
- Providing a lead apron if she wishes to remain in controlled areas during portable imaging or fluoroscopy, although this is not a substitute for distance and shielding.
The decision should be based on the measured waist badge, not on fear alone. A review after the first month of waist-badge data is sensible. If the projected fetal dose approaches 0.5 mSv, reduce treatment-unit time further. If it remains very low, continuing selected duties is compatible with ALARA. Document the risk assessment, her preferences, and the review dates.
3. What communication, confidentiality and ethical issues arise from her declaration?
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Reasoning
Pregnancy declaration is voluntary. The radiographer should not be pressured to disclose, and disclosure should be handled confidentially and only shared with those who need to know for the risk assessment, such as the line manager, radiation protection supervisor, and occupational health. She should be told why a waist badge is needed, what the dose limits and local targets are, and what adjustments are available.
Ethical points:
- Avoid discriminatory assumptions about her ability or willingness to work. The starting point is that pregnant workers can continue in radiation work with appropriate monitoring and adjustments.
- Respect her choice. If she declines to declare, standard whole-body monitoring continues, but the legal fetal dose limit cannot be applied and adjustments may be harder to justify.
- Explain that the 1 mSv limit is protective and that the department will review her dose monthly.
- Record the discussion and any agreed changes. Ensure colleagues are briefed only on a need-to-know basis and avoid informal gossip.
- Offer occupational health support and a review point if her circumstances change.
The manager's staffing pressure is not a lawful reason to refuse adjustments or to expose her to unnecessary dose.