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Lesson: Nuclear Radiation in Medicine

Question Video: Understanding Radioactive Tracers


Worksheet: Nuclear Radiation in Medicine • 8 Questions


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

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


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, e, f
  • Bc, d, e
  • Ca, d, f
  • Dc, d, f
  • Eb, c, e


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

  • ASievert (Sv)
  • BJoule (J)
  • CBecquerel (Bq)
  • DWatt (W)
  • EHertz (Hz)