1. Exercise
a) In a sample of 20 000 atoms, if 400 decay in 8 seconds, what is the de radioactivity measured in mCi of the sample?
b) In orde to produce a level of radioactivity of 1 mCi, how many nuclei of 99mTc (λ =3.22x10^-5 s^-1)must be present? What mass of the radiotracer does this correspond to? (Avogrado´s number is 6.02x10^23)
c) A radioactive sample of 99mTc contains 10mCi activity at 9am. What is the radioactivity of the sample at 12 pm on the same day?
2. Exercise
A dosage of 18F-FDG has 20mCi at 10am wednesday. Calculate the activity of the dosage at 7am anda 2pm that day. Tha half life of 18F is 110min.
