$^{131}I$ 3700 MBq (100 mCi) Therapy 입원 환자의 선량률(${\mu}Sv/h$), 잔류량(mCi), 배설률(%) 측정

Investigations of the External Dose Rate (${\mu}Sv/h$), the Residual Activity (mCi) and the Excretion Rate (%) of Thyroid Cancer Patients Hospitalized for 3700 MBq (100 mCi) $^{131}I$ Radioiodine Treatment

목적 : 현재 원자력법에 환자의 입원치료, 외래치료의 기준 용량(mCi)과 선량률(${\mu}Sv/h$)이 명확히 고시되어 있지 않아, (IAEA, BSS)기준에 따라 환자를 퇴원시킨다. 그래서 $^{131}I$ 3700 MBq (100 mCi)를 투여하는 갑상선암 치료환자에게 입원기간 동안 선량률(${\mu}Sv/h$)을 측정하여 선량률(${\mu}Sv/h$)과 잔류량(mCi), 배설률(%)에 따라 $^{131}I$ 3700 MBq (100 mCi)가 70%가 감소하여 1110 MBq (30 mCi)가 되는 시간을 확인하여 치료환자들의 퇴원기준 설정에 참고 자료가 되고자 한다. 실험재료 및 방법 : 갑상선제거수술을 받고 $^{131}I$ 3700 MBq (100 mCi)을 투여하는 환자 중 신장 기능에 이상이 없는 42명을 대상으로 하였다. 측정기는 Thermo사의 FH40G-L을 사용하여 $^{131}I$ Capsule을 개봉하고서 $^{131}I$ 3700 MBq (100 mCi)을 투여 후 즉시부터, 거리와 높이 1m에서 1, 2, 4, 8, 20, 24, 40시간째 소변 전/후 20초간 평균 측정하였다. 결과 및 결론 : (IAEA, BSS) 기준에 따라 $^{131}I$ 3700 MBq (100 mCi)를 투여한 후 20시간째 $49{\pm}13\;{\mu}Sv/h$로 100%에서 78%가 배설하여 체내에 814 MBq (30 mCi)가 잔류하여 퇴원 가능한 체내 잔류량 1110 MBq (30 mCi) (1 m에서 $66\;{\mu}Sv$/h) 이하를 만족하였다.

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(${\mu}Sv/h$) of inpatient underwent 3700MBq (100 mCi) $^{131}I$ radioiodine treatment and considering external dose rate(${\mu}Sv/h$), 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 $^{131}I$ 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(${\mu}Sv/h$) 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 $49{\pm}13\;{\mu}Sv$/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).