Estimation of radiation exposure to family members of patients treated with I-131 in Tanzania

Radiation therapy using Iodine-131 (I-131) is a widely employed treatment for thyroid disorders; however, it poses potential radiation exposure risks to patient caregivers due to gamma emissions from treated patients.This study estimates the radiation doses received by family members of patients undergoing I-131 therapy in Tanzania, where cultural practices and living conditions complicate adherence to international safety guidelines.Using the Particle and Heavy Ions Transport-code System (PHITS), exposure scenarios during hospitalisation and post-discharge phases were modelled, accounting for proximity, activity levels, and caregiver-patient interactions.These models were utilised to estimate the radiation exposure to family members of patients treated with I-131 in Tanzania.Results indicate that family members assisting dependent patients during hospitalisation received doses of 1.53, 2.33, and 2.99 mSv for 3700, 5550, and 7400 MBq, respectively.These doses are below the 5 mSv/episode limit but exceed the 1 mSv/year public dose limit.