Analysis on Distribution of Effective Dose Rate around Patients for Treatment of Thyroid Cancer with I-131

It is required to evaluate the effective dose rate that may influence the family and caregivers of patients in order to realize the radiation protection for people around thyroid cancer patients when treating them with the administration of I-131. To this end, this study measured the surrounding effective dose rate that is emitted in accordance with the rotation angle of patients. For accurate measurement, this study analyzed the height, rotation angle and elapsed time at the distance of 90 cm by manufacturing a wooden frame of geometric form. The surrounding effective dose rate distribution for vertical plane was the highest at the distance of 100 cm and height of 90 cm from the patients 24 hours after the oral administration of I-131 with the mean of 80.77±4.2 μSv/h. This study conducted the experiment based on the three groups, which were the control group of normal fluid intake (2 liter/day), the experimental group A (1 liter/day) with a small amount of fluid intake and the experimental group B (3 liter/day) with a larger amount of fluid intake than the normal fluid intake, in relation to the reduction degree of surrounding effective dose rate through fluid intake. AS for the dose distribution at the distance of 100 cm and the height of 90 cm 24 hours after the oral administration of I-131, the experimental group A had 101.2 μSv/h, whereas the experimental group B had 37.24 μSv/h and the control group had 72.58 μSv/h. As a result of comparing the control group with the experimental group A and B, this study confirmed the reduction effect of radiation exposure by approximately 51 percent depending on the extent of fluid intake when treating thyroid cancer patients with I-131.