QUESTION ANSWER 1. Calculate the specific activity (in Ci/g) of 2.5 grams of Xe- 133 with 1.85 x 1018 dps. 2. A radionuclide has a half-life of 6 hours. If its activity is currently 5,500 dom, what will its activity be 4 hours from now? 3. How many dps are there in 15 mCi? 4. For Xe-133 in pulmonary ventilation study, the biological half-life is 15 seconds. Calculate the its effective half-life. 5. A radiopharmaceutical has a biological half-life of 4 hours and an effective half-life of 3.075 hours. What isotope was used? 6. A Tc-99m compound has an effective half-life of 1 hour. What is its biological half-life? 7. 1.1 x 103 Ci is equal to how many GBq? 8. The initial activity of I-131 is 30 mCi. What will be its remaining activity after 15 days