According to the radiactive decay law, the activity of the sample at the time t is given by the expression:
A(t)=A(0)⋅2−Ttwhere A(0)=1900 MBq is the activity at the initial moment of time and T=6 hours is the half-life of Technetium-99m.
The time was passed between 06:00, 18th June 2014 and 07:00, 19th June 2014 is 25 hours. Thus, the activity will be:
A(25)=1900 MBq⋅2−625=105.8 MBq To convert this number to Ci, one should multiply it by 2.7⋅10−11 . Thus:
A=105.8⋅106 Bq=105.8⋅106⋅2.7⋅10−11Ci≈2.86 mCi Answer. A = 105.8*10^6, A = 2.86*10^(-3) Ci.
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