Hazards, Uses of Radioactive Emissions Background Radiation

• What is background radiation?

  The radiation that exists around us all the time
• Why has human activity affected 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 is a natural source of background radiation?

  Radon gas from some types of rock

  
• What are examples of man-made sources of background radiation?

  Nuclear weapons fallout and medical testing
• What is the background radiation count determined by in a Geiger-counter experiment?

  Results after 1 metre from the source
• What is the background radiation count measured in the example?

  15 counts per minute
• How is the dose of radiation measured?

  In sieverts (Sv)
• What does one sievert represent?

  A very big dose causing acute radiation poisoning
• What is the typical annual radiation dose received by a person?

  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 source of cosmic rays?

  Particles from the Sun or nearby stars
• How do cosmic rays interact with the Earth's atmosphere?

  They send showers of smaller particles down
• What is the purpose of a dosemeter?

  To measure the amount of radiation received
• How does a person's occupation affect radiation exposure?

  Some jobs expose individuals to higher radiation
• What is the UK limit for nuclear industry employees' radiation dose?

  20 mSv in one year
• What is emitted by all living things, including bananas?

  A small amount of radiation
• What are the three different units related to radiation?

  • Becquerels (Bq): amount of radiation emitted
  • Counts per second (cps): rate of radiation hitting a location
  • Sieverts (Sv): received dose of radiation
• What is the definition of half-life?

  The time for activity to decrease by half
• Which isotope has a half-life of 1 millisecond?

  Francium-218
• Which isotope has a half-life of about 700 million years?

  Uranium-235
• What happens if an isotope has a short half-life?

  It decays quickly and emits a lot of radiation

  
• What is the risk of using isotopes with long half-lives?

  They present a risk of long-term contamination
• 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
• What type of radiation is usually used for medical tracers?

  Gamma emitters
• Why are gamma rays chosen for medical tracers?

  They are highly penetrating and detectable
• What is an example of a radioactive tracer?

  Iodine-131
• Why is the amount of isotope used in medical procedures minimized?

  To reduce people's exposure to radiation
• What is radiotherapy used for?

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

  By rotating beams to target the tumor
• What is the purpose of internal radiotherapy?

  To expose the tumor directly to radiation
• Why is gamma radiation used to sterilize medical equipment?

  It is the most penetrating type of radiation
• What are the requirements for a suitable medical tracer?

  Penetrate the body and have a short half-life
• What are the risks associated with the use of radiation in medicine?

  Kill or damage cells, cause cancer
• Why might the benefits of radiation outweigh the risks in some medical cases?

  Risks are smaller than untreated conditions
• What should you consider when evaluating the risk of nuclear radiation?

  • Compare potential dangers with benefits
  • Assess the severity of untreated conditions