Calculating Time Needed for 1.0 mCi of 3215P to Deliver 36 Gy

[Rath123]

A 1.0 mCi source of 3215P (in NaHPO4), a β emitter, is implanted in a tumor where it is to administer 36 Gy. The half-life of 3215P is 14.3 days and 1 mCi delivers about 10 mGy/min. Approximately how long should the source remain implanted?

I'm calculating 2.19 days but doing something wrong, because this answer is incorrect? any ideas?! thanks

 

[SteamKing]

A 1.0 mCi source of 3215P (in NaHPO4), a β emitter, is implanted in a tumor where it is to administer 36 Gy. The half-life of 3215P is 14.3 days and 1 mCi delivers about 10 mGy/min. Approximately how long should the source remain implanted?

I'm calculating 2.19 days but doing something wrong, because this answer is incorrect? any ideas?! thanks

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