Estimation of radiation exposure to family members of I-131-treated patients in Tanzania using PHITS simulations

Tóm tắt

Radiation therapy using Iodine-131 (I-131) is a widely employed treatment for thyroid disorders; however, it poses potential radiation 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 Ion 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 used to quantify 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 per episode limit but exceeding the 1 mSv annual public dose limit recommended by the International Commission on Radiological Protection (ICRP). Post-hospitalisation, the doses decreased significantly, with the highest exposure caused by close-contact activities. Meanwhile, transportation scenarios showed the exposure to be less than 1 mSv/year for short durations. Nevertheless, strict adherence to maintaining a one-metre distance and minimising the duration of close contact is emphasised. These findings provide critical insights for maintaining public health while ensuring effective thyroid cancer treatment.