Abstract
The Iodine Therapy is rapidly increasing and is becoming one of the most common treatment modality for thyroid cancer, in this type of treatment the thyroid is treated with large doses of radioactive iodine, this dose is much higher than the other thyroid treatments; which then is putting high demand from radiation protection point of view. The main objective of the present study was to investigate what is the optimum time for patient discharge. This is done by analyzing the radiation dose rate levels emitted from the patients following I-131 administration, and compares it with the maximum allowed dose rate according to the national regulations. To do that,74 thyroid cancer patients were included in this study, in which the radiation emitted from patients was measured at 1m distance from patients using a survey meter at various time intervals 48, 72 and 96 h after administration. Patients were divided into groups according to body mass indexes BMI; underweight <18.5 normal range between 18.5 and 24.9, overweight from 25 up to 29.9, and obese for BMI ≥30. All patients were discharged after 96h from dose administration. The mean radioactivity administered to the patients was 113.8 ± 17.6 mCi, with a range between 80 mCi to a maximum of 170 mCi. The radiation dose rate was found to be 30.3 ± 14.1 μSv h−1, 18.7 ± 12 μSv h−1, and 11.7 ± 7.9 μSv h−1 at 1 m distance from the patient's neck level after 48h, 72 and 96 h respectively. Our results showed that regardless of the patient gender, and administrated dose, the external dose rate values increases as BMI increases except for underweight group. It was concluded that The BMI values may be taken into account in the radiation protection optimization process.
•The external dose rate values in thyroid cancer patients treated with I131 decrease as BMI increases.•The external dose rate values in normal BMI range patient group were higher compared to other groups.•Three days may be considered an appropriate isolation period.