Radiopharmaceuticals are used to deliver a high dose of radiation to target tiss
ID: 1510886 • Letter: R
Question
Radiopharmaceuticals are used to deliver a high dose of radiation to target tissues in a patient, e.g. a tumor. The drug is designed to be preferentially absorbed by the target tissue and so carries the radioactive source into the target. Consider a patient who swallows a radiopharmaceutical that, utilizes phosphorus-32 (^32_15P), beta^- emitter with a half-life of 14.3 days. The average kinetic energy of the emitted electrons is 744 keV. If the initial sample contained 1.06 times 10^14 atoms, find the number of decays that occur in a 15-day period. Answer in units of decays. (part 2 of 3) 10.0 points Find the total energy of the radiation emitted during the 15 days. Answer in units of J. (part 3 of 3) 10.0 points Find the absorbed dose if the electrons are completely absorbed in the target tissue which has a mass of 149 g. Answer in units of Gy.Explanation / Answer
1) Here, number of decays = 1.06 * 1014 * (0.693/14.3) * 15
= 7.705 * 1013 decays
2) total energy radiated = 744 * 1000 * 1.6 * 10-19 * 15
= 1.7856 * 10-12 J
3) absorbed dose = 1.7856 * 10-12 /0.149
= 1.2 * 10-11 Gy
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