Worksheet: Nuclear Radiation in Medicine

In this worksheet, we will practice determining the suitability of a radioisotope for use in different medical applications.

Q1:

Polonium-210 is a radioactive isotope of polonium with a half-life of 138 days. It decays via alpha decay to lead. Which of the following are reasons why polonium-210 cannot be used as a radioactive tracer?

  1. Polonium-210 is too expensive to be used as a radioactive tracer.
  2. Polonium-210 decays too slowly and thus would remain in a person’s system for too long.
  3. Polonium-210 is a very rare isotope, and thus refining it for use in medicine is too difficult.
  4. Polonium-210 decays too quickly and thus would not remain in a person’s system long enough to be useful.
  5. Polonium-210 decays to lead, which is highly toxic.
  6. Polonium-210 decays via alpha decay. Radioactive tracers have to emit gamma rays. The alpha particles released by polonium would be absorbed by the body’s cells.
  • Ab, c, e
  • Ba, d, f
  • Cc, d, f
  • Db, e, f
  • Ec, d, e

Q2:

Which of the following correctly explains why gamma radiation is used for radiation beam therapy rather than alpha or beta particles?

  • AGamma radiation is more easily contained than alpha and beta radiations.
  • BGamma radiation is more ionizing than alpha or beta radiation and is therefore more effective in destroying cancerous cells.
  • CGamma-ray sources have longer half-lives than alpha and beta sources and therefore do not have to be replaced as often.
  • DGamma radiation can penetrate further into the body than alpha or beta radiation and can thus reach the organs that contain cancerous tissue.
  • EGamma-ray sources are cheaper than alpha and beta sources.

Q3:

Which of the following is the correct unit for ionizing radiation dose?

  • AHertz (Hz)
  • BBecquerel (Bq)
  • CWatt (W)
  • DSievert (Sv)
  • EJoule (J)

Q4:

Polonium-218 is a radioactive isotope with a half-life of 3.1 minutes. It can decay via alpha decay or beta decay. Which of the following correctly explains why polonium-218 is not suitable for use in gamma-ray beam therapy?

  • AThe half-life of Polonium-218 is too long, and thus a very large sample of it is needed to produce enough gamma rays to be useful.
  • BPolonium-218 decays to lead, which is highly toxic; thus, the radioactive waste is difficult to dispose of.
  • CPolonium-218 is very expensive.
  • DPolonium-218 does not emit any gamma rays.

Q5:

The table shows four different radioactive isotopes. Which isotopes would be suitable for use in a radioactive implant?

Isotope Rubidium-82 Cobalt-60 Ruthenium-106 Radon-222
Decay Type 𝛽 𝛽 , 𝛾 𝛽 𝛼
Half-Life 1.27 minutes 5.27 years 1.02 years 3.82 days
  • ARubidium-82 and radon-222
  • BRubidium-82 and ruthenium-106
  • CCobalt-60 and radon-222
  • DCobalt-60 and ruthenium-106
  • ECobalt-60 and rubidium-82

Q6:

Rubidium-82 is a radioactive isotope of rubidium that decays via beta decay with a half-life of 1.27 minutes. Which of the following correctly explains why rubidium-82 is not suitable for use in radioactive implants?

  • ARubidium-82 decays too slowly to be of any use in radioactive implants.
  • BRadioactive implants require an isotope that decays via alpha decay, but rubidium-82 decays via beta decay.
  • CRubidium-82 does not exist naturally and producing it would be too expensive.
  • DRubidium-82 decays too quickly to be of any use in radioactive implants.

Q7:

The table shows five different radioactive isotopes. Which isotopes would be suitable for use in gamma-ray beam therapy?

Isotope Iridium-192 Neodymium-144 Cesium-137 Uranium-238 Polonium-218
Decay Type 𝛽 , 𝛾 𝛼 𝛽 , 𝛾 𝛼 𝛼 , 𝛽
Half-Life 73.8 days 2 . 3 × 1 0   years 30.2 years 4 . 5 × 1 0  years 3.1 minutes
  • ANeodymium-144 and polonium-218
  • BIridium-192 and polonium-218
  • CNeodymium-144 and uranium-238
  • DIridium-192 and cesium-137
  • ECesium-137 and uranium-238

Q8:

The table shows four different radioactive isotopes. Which isotopes would be suitable for use as radioactive tracers?

Isotope Iodine-129 Technetium-99m Rhodium-106 Iodine-123
Decay Type 𝛽 , 𝛾 𝛾 𝛽 , 𝛾 𝛾
Half-Life 15.7 million years 6 hours 30 seconds 13.2 hours
  • AIodine-129 and rhodium-106
  • BIodine-129 and technetium-99m
  • CRhodium-106 and iodine-123
  • DTechnetium-99m and iodine-123

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