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

Objectives Ra-223 is used for the medicine of castration-resistant prostate cancer (CRPC) and which emits α-ray of 2 Mev that is used for therapy. However Ra-223 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 Ra-223.

Methods We calculated external radiation expose dose rate using γ-constant of Ra-223, 99mTc based on ICRP 107. Ra-223 of 3.5 MBq and 99mTc of 740 MBq were applied. external radiation expose dose rate 15 times from 1 cm, 1m by survey meter

Results γ-contant of Ra-223, 99mTc from 1m distance based on ICRP 107 is 0.0469, 0.0215. calculated value of external radiation expose dose rate was 16 ㎲v, 34 ㎲v which activity is Ra-223 of 3.5 MBq and 99mTc of 740 MBq from 1 m . measured mean value of 10 cm distance was 120 ㎲v/h , 1810 ㎲v/h. and which of 1 m was 0.7 ㎲v/h, 18 ㎲v/h .

Conclusions : γ-constant of 223-Ra is higher than 99mTc based on ICRP 107. however calculated maximum external radiation expose dose rate of 223-Ra is lower than 99mTc due to actually used quantity of activity of Ra-223 is small. measured value of Ra-223 is also lower than 99mTc. Therefore external radiation expose dose rate of γ-ray of Ra-223 is very low.