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서울대학교병원 핵의학과

조성욱·윤석환·승종민·김태엽·임정진·김진의

The Evaluation of External Radiation Exposure dose rate for Radium-223 Dichloride

Seong Wook Cho, Seok Hwan Yoon, Jong Min Seung, Tae Yub Kim, Jeong Jin Im, Jin Eui Kim

Department of Nuclear Medicine, Seoul National University Hospital

Purpose :

223Ra-Dichloride is used for the medicine of castration-resistant prostate cancer (CRPC) and which

emits α-ray of 28 Mev that is used for therapy. However 223Ra-Dichloride emits β-ray of 3.6% and

γ-ray of 1.1%(80,156,270 keV) aside from α-ray in decay. Therefore we would like to evaluate

external radiation expose dose rate of γ-ray of 223Ra-Dichloride.

Materials and Methods :

We calculated external radiation expose dose rate using γ-constant of 223Ra-Dichloride, 99mTc based

on Health physics(2012). 223Ra-Dichloride of 3.5 M㏃ and 99mTc-MDP of 740 M㏃ were applied. external

radiation expose dose rate 15 times from 1m by survey meter.

Results :

γ-contant of 223Ra, 99mTc-MDP from 1m distance based on Health physics(2012) is 0.0469, 0.0215.

calculated value of external radiation expose dose rate was 16 μ㏜, 34 μ㏜ which activity is

223Ra-Dichloride of 3.5 MBq and 99mTc-MDP of 740 M㏃ from 1 m . and measured mean value of 1 m

was 0.7 μ㏜/h, 18 μ㏜/h.

Conclusion :

γ-constant of 223Ra is higher than 99mTc based on Health physics(2012). however calculated maximum

external radiation expose dose rate of 223Ra-Dichloride is lower than 99mTc due to actually used

quantity of activity of 223Ra-Dichloride is small. measured value of 223Ra-Dichloride is also lower

than 99mTc-MDP. Therefore external radiation expose dose rate of γ-ray of 223Ra-Dichloride is very

low.

Key Words : 223Ra-Dichloride, external radiation expose dose