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

Introduction: The relation between patient Body Mass Index (BMI) and the external dose rate of thyroid cancer patients treated with 131I has been investigated. Methods: 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. Results: 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. Conclusion: 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.