The impact of body mass index on the external dose rate from patients treated with radioiodine-131: A preliminary study

The relation between patient Body Mass Index (BMI) and the external dose rate of thyroid cancer patients treated with 131I has been investigated. A total of 183 patients treated with 131I were selected randomly and divided according to their administrated activity into three groups: 3.7GBq, 5.5GBq and 7.4GBq. They were also stratified into three groups according to their BMI values namely normal, overweight and obesity. A telescopic radiation survey meter was used to measure the dose rate at 1 meter from patient neck level. The measurement was effectuated after 1, 24 and 48 hours post dose administration. Our findings showed that regardless the patient sex, age, and administrated dose, the external dose rate values in normal BMI range patient group were higher by 11% (as an average) as compared to overweight and obesity groups when the dose administrated was 150 and 200 mCi while it was higher by 49% for patient received 100 mCi. The BMI patient value may be taken into account in the radiation protection optimization process by the physicist during isolation period and general public after patient discharge.