Question

. A vial of 67 Ga containing 200 mCi of was received in a 7ml vial at 8:00am this morning. (The
half-life (T 1/2 ) for 67 Gallium is 78.24 hours).

What will the activity of the vial be at tomorrow at 8:00am?

What is the current concentration?

explain how you did it

If you need to deliver 3mCi to a patient today at 8:00, how much should you draw up in milters?

Answer 1

After t hours , activity decreases by e- t

where is decay constant, = 0.693/T1/2 and T1/2 is half life period

= 0.693 / 78.24 = 8.859 10-3 hr-1

Hence at next day 8-00 AM, after 24 hours remaining activity =

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Current concentration = 200 mCi / 7 ml = 28.57 mCi / ml

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To deliver 3 mCi, required volume = ( 1/28.57 ) 3 = 0.105 ml