Radiation safety considerations for post-iodine-131 hyperthyroid therapy

Area of Science:

• Nuclear Medicine
• Radiological Health

Background:

• Hyperthyroidism is a common endocrine disorder.
• Radioiodine therapy using iodine-131 (131I) is an effective treatment for hyperthyroidism.
• Establishing safe patient release criteria is crucial for public health.

Purpose of the Study:

• To develop evidence-based guidelines for resuming close personal contact after iodine-131 (131I) therapy for hyperthyroidism.
• To determine safe timeframes for patient release based on measured radiation exposure rates.

Main Methods:

• External exposure rates were measured in 59 hyperthyroid patients post-131I administration using an ionization survey meter.
• Measurements were taken at various distances (1, 0.6, and 0.3 meters) and time points (Day 0 and Days 2-11).
• Patients received administered doses ranging from 3 to less than 12 mCi of 131I.

Main Results:

• On Day 0, all measured patients (n=40) had exposure rates ≤2.0 mR/hr at 1 meter.
• On Days 2-4, 25 out of 29 patients had exposure rates ≤2.0 mR/hr at 0.6 meters.
• These findings indicate decreasing radiation levels within the first week post-treatment.

Conclusions:

• Rational guidelines for patient release after 131I therapy can be established based on administered dose.
• The developed guidelines align with existing radiologic health standards.
• This research supports informed decision-making for safe patient contact post-treatment.