91Ó°ÊÓ

A patient is reported to have been irradiated by a dose of 1 sievert in a nuclear accident. Is he in mortal danger?

Explain the following: (a) It is impossible to have a completely pure sample of any radioactive isotope. (b) Beta emission of a radioactive isotope creates a new isotope with an atomic number one unit higher than that of the radioactive isotope.

Yttrium- \(90,\) which emits beta particles, is used in radiotherapy. What is the decay product of yttrium- \(90 ?\)

The half-lives of some oxygen isotopes are as follows: Oxygen-14 \(=71\) s \(\quad\) Oxygen- \(15=124\) s Oxygen-19 \(=29\) s Oxygen-20 \(=14\) s Oxygen-16 is a stable, nonradioactive isotope. Do the half-lives indicate anything about the stability of the other oxygen isotopes?

\(225 \mathrm{Ac}\) is effective in prostate cancer therapy when 89 administered at kBq levels. If an antibody tagged with \(225 \mathrm{Ac}\) has an intensity of 2 million Bq/mg and if 889 a solution contains \(5 \mathrm{mg} / \mathrm{L}\) tagged antibody, how many milliliters of the solution should you use for an injection to administer 1 kBq intensity?

When \(208 \mathrm{Pb}\) is bombarded with \(^{64} \mathrm{Ni}\), a new element 82 and six neutrons are produced. Identify the new element.

A \(0.4 \mathrm{mg}\) initial sample of radioactive iodine- \(123,\) used to treat thyroid cancer, decreases to \(0.1 \mathrm{mg}\) in 26.4 hours. What is the half-life of iodine- \(123 ?\)

The half-life for the radioactive decay of thallium-201 is 3.0 days. If a sample decays to \(4.0 \mu \mathrm{Ci}\) in 12 days, what was the initial activity, in microcuries, of the sample?

The half-life of oxygen-15 is 124 seconds. If a sample of oxygen-15 has an activity of 6000 Bq, how many minutes will elapse before it has an activity of 375 Bq?

Americium-241, the isotope used in smoke detectors, has a half-life of 432 years, which is sufficiently long to allow for handling it in large quantities. This isotope is prepared in the laboratory by bombarding plutonium-239 with \(\alpha\) particles. In this reaction, plutonium-239 absorbs two neutrons and then decays by emission of a \(\beta\) particle. Write an equation for this nuclear reaction and identify the isotope formed as an intermediate between plutonium-239 and americium- -241