4.3 Hazards & Uses of Radioactive Emissions and Background

• What is background radiation?

  The radiation that exists around us all the time
• Why has human activity increased background radiation levels?

  Human activity has added to the radiation exposure
• What are the two types of background radiation sources?

  • Natural sources
  • Man-made sources
• What are cosmic rays?

  Particles from space that contribute to radiation
• What does a dosemeter measure?

  The amount of radiation in particular areas
• What is the unit of measurement for radiation dose?

  Sieverts (Sv)
• What is the typical annual radiation dose a person receives?

  About 3 mSv (0.003 Sv)
• What are the differences between background radiation and cosmic microwave background radiation (CMBR)?

  • Background radiation: constant low-level radiation on Earth
  • CMBR: radiation from the Big Bang, stretched to microwave region
• What is the half-life of Francium-218?

  1 millisecond (0.001 seconds)
• What is the half-life of Uranium-235?

  About 700 million years
• Why can short half-life isotopes be advantageous?

  They quickly lose their radioactivity
• What is a risk of long half-life isotopes?

  They remain radioactive for a long time
• What are the misconceptions about radioactive decay?

  • Mass decreases with each decay
  • Short half-lives emit more radiation per decay
• What is a medical tracer?

  A radioactive isotope tracking substances in the body
• Why are gamma emitters used as medical tracers?

  They are highly penetrating and detectable
• What is the purpose of radiotherapy?

  Treating cancer using radiation
• How does external radiotherapy minimize damage to healthy tissue?

  By rotating beams to target the tumor
• What is the main use of gamma radiation in medicine?

  Sterilizing medical equipment
• Why is gamma radiation suitable for sterilizing medical equipment?

  It is the most penetrating type of radiation
• What are the risks associated with the use of radiation in medicine?

  It can kill cells and cause cancer
• Why might the benefits of radiation outweigh the risks in some medical situations?

  Radiation can treat life-threatening conditions
• What factors affect background radiation levels and radiation dose?

  • Occupation (e.g., nuclear industry workers)
  • Location (proximity to radiation sources)