¹³¹I 3700 MBq (100 mCi) Therapy 입원 환자의 선량률(μSv/h), 잔류량(mCi), 배설률(%) 측정

Investigations of the External Dose Rate (μSv/h), the Residual Activity (mCi) and the Excretion Rate (%) of Thyroid Cancer Patients Hospitalized for 3700 MBq (100 mCi) ¹³¹I Radioiodine Treatment

Purpose: As Korean nuclear law doesn’t have any clear guideline about the dose and the external dose rate(uSv/h) requiring hospitalization in radioactive iodine treated patients, the patients are discharged when they meet the guideline of IAEA Basic Safety Standards(BSS). We measured external dose rate(μSv/h) of inpatient underwent 3700MBq (100 mCi) ¹³¹I radioiodine treatment and considering external dose rate(μSv/h), residual activity(mCi) and excretion rate(%) we found the time for RA to be lowered from 3700MBq (100 mCi) to 1110 MBq (30 mCi) to give reference to set a guideline for discharge. Materials and Methods: Forty-two patients underwent thyroidectomy and scheduled for radioiodine treatment, who received 3700MBq (100 mCi) of ¹³¹I orally and had no renal disease were examined. After 1, 2, 4, 8, and 20, 24, 40 hours iodine uptake and before/after the urination, the external dose rate(μSv/h) measured using FH40G-L(Thermo Fisher Scientific Inc., MA) at a distance and a height of 1 m for 20 sec on the average. Results and Conclusions: At 20 hours, the external dose rate was decreased to 49±13 μSv/h, namely, 78% of administrated radioactivity was excreted and 814 MBq (30 mCi) was residual, and it met the accepted limit for discharge of (IAEA, BSS) under 1110 MBq (30 mCi) (1 m at 66 uSv/h).