- A radiopharmaceutical has a biologic half-life of 10 hr in humans
and a physical half-life of 23 hr. What is the effective half-life of the
radiopharmaceutical? - If the radioactivity of^111 In (t1/2=2.8 days) is 200 mCi (7.4 GBq) on
Monday noon, what is the activity (a) at 10:00 a.m. the Friday before
and (b) at 1:00 p.m. the Wednesday after? - How long will it take for a 10-mCi (370-MBq) sample of^123 I (t1/2=
13.2 hr) and a 50-mCi (1.85-MBq) sample of 99mTc (t1/2=6 hr) to possess
the same activity? - What is the time interval during which^111 In (t1/2=2.8 days) decays to
37% of the original activity? - For antibody labeling, 5 mCi of^111 InCl 3 is required. What amount of
(^111) InCl
3 should be shipped if transportation takes 1 day?
- What are the specific conditions of transient equilibrium and secular
equilibrium? - How long will it take for the decay of 7/8 of an^18 F (t1/2=110 min)
sample? - What fraction of the original activity of a radionuclide has decayed in
a period equal to the mean life of the radionuclide? - A radioactive sample initially gives 8564 cpm and 2 hr later gives
3000 cpm. Calculate the half-life of the radionuclide. - If Natoms of a sample decay in one half-life, how many atoms would
decay in the next half-life? - The^99 Mo (t1/2=66 hr) and 99mTc (t1/2=6 hr) are in transient equilibrium
in a Moly generator. If 600 mCi (22.2 GBq) of^99 Mo is present in the
generator, what would be the activity of 99mTc 132 hr later, assuming that
87% of^99 Mo decays to 99mTc? - A radionuclide decays with a half-life of 10 days to a radionuclide
whose half-life is 1.5 hr. Approximately how long will it take for the
daughter activity to reach a maximum?
Suggested Readings
Cherry SR, Sorensen JA, Phelps ME. Physics in Nuclear Medicine. 3rd ed.
Philadelphia: W. B. Saunders; 2003.
Friedlander G, Kennedy JW, Miller JM.Nuclear Chemistry and Radiochemistry. 3rd
ed. New York: Wiley; 1981.
Saha GB.Fundamentals of Nuclear Pharmacy. 5th ed. New York: Springer-Verlag;
2004.
Suggested Readings 33