Pregnant Technologist and a High-Activity I-131 Therapy
A nuclear medicine technologist who is 10 weeks pregnant is assigned to a day that includes an I-131 thyroid ablation for a 70-year-old woman (administered activity 150 mCi) and several diagnostic studies. The department's radiation safety officer has a declared-pregnancy policy. The therapy room is 30 feet from the diagnostic camera room. The technologist's personal dosimeter reading from the prior month was 0.8 mSv. The therapy patient will need post-administration instructions and room preparation.
1. What should the technologist do regarding the I-131 therapy assignment?
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Declare the pregnancy and follow the radiation safety policy.
- The technologist should notify the RSO and supervisor of the pregnancy in writing per the declared-pregnancy policy so that dose constraints and work restrictions can be applied.
- I-131 therapy involves high activity, volatile iodine, and significant exposure potential; pregnant workers are typically restricted from high-dose therapy administration and from handling volatile radioiodine. The assignment should be reassigned to another technologist.
- The prior 0.8 mSv monthly reading is within typical limits but is not the deciding factor; the declared-pregnancy policy and ALARA for the fetus govern.
2. Can the technologist safely perform the diagnostic studies that day?
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Likely yes, with attention to distance and time.
- Diagnostic studies (e.g., Tc-99m bone scan, renal scan) involve much lower activities and external exposure; with standard precautions (distance, shielding, time), the fetal dose is typically small.
- Practical measures: prepare and inject doses behind shielding, maintain distance from the injected patient during uptake, avoid holding patients, and rotate assignments. The therapy room 30 feet away is not a major contributor if the technologist does not enter it.
- The RSO should confirm the specific restrictions and any fetal dose monitoring. Document the discussion and the plan.
3. What post-administration instructions and room precautions apply to the I-131 therapy patient, and how does the technologist's role change?
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The therapy patient needs standard radiation safety instructions, but the pregnant technologist should not deliver them in person.
- Typical instructions: maintain distance from others (especially pregnant women and children), sleep separately for a period, flush twice, use separate utensils, and follow local release criteria. These are given by the authorized user or a designated technologist.
- Room preparation (lining, signage, dedicated supplies) and post-therapy surveys are performed by staff not restricted by pregnancy. The pregnant technologist should not enter the therapy room.
- The technologist should ensure the patient receives the instructions from an appropriate staff member and that documentation is complete, while remaining outside the restricted area.