uses and dangers of radiation

• What is the process of exposing objects to beams of radiation called?

  Irradiation
• Why does shining a torch beam on a hand light it up?

  Because the hand has been exposed to light
• What types of radiation does the term irradiation apply to?

  All types of radiation including radiation from the nuclei of atoms
• How can irradiation from radioactive decay affect living cells?

  It can damage living cells
• How is irradiation used to preserve fruit sold in supermarkets?

  By exposing the fruit to a radioactive source like cobalt-60
• What do gamma rays emitted by cobalt-60 do to bacteria on fruit?

  They destroy any bacteria on the fruit
• Does the process of irradiation cause the irradiated object to become radioactive?

  No, it does not cause the irradiated object to become radioactive
• What is one medical use of irradiation?

  Sterilisation of surgical instruments
• What is a gamma knife used for?

  To kill cancerous tumours deep inside the body
• How are gamma rays aimed at a tumour during treatment?

  From many different directions to maximise the dose on the tumour
• Why is it important to calculate the dose of gamma rays carefully?

  To kill the tumour without damaging surrounding healthy tissue
• What factors are considered to ensure that medical irradiation does not cause long-term effects?

  The nature of decay, half-life, and toxicity
• What happens if the half-life of a radioactive source is too long?

  The damaging effects of the radiation would last too long
• What is one advantage of using irradiation for sterilisation?

  Sterilisation can be done without high temperatures
• What is one disadvantage of irradiation?

  It may not kill all bacteria on an object
• What is contamination?

  When an object has radioactive material introduced into it
• How is an apple that is irradiated different from one that is contaminated?

  An irradiated apple is exposed to radiation, while a contaminated apple has radioactive material injected into it
• How can injected radioactive sources be used in medical imaging?

  As tracers to make soft tissues show up
• What do gamma rays emitted from isotopes do in medical imaging?

  They easily pass through the body to a detector outside
• What can changes in the amount of gamma emitted indicate?

  How well the isotopes are flowing or if there is a blockage
• What precautions are taken to ensure contamination does not cause long-term effects?

  Choosing isotopes with very short half-lives and that are not poisonous
• How can contamination be used to check for leaks in water supplies?

  By using a gamma-emitting radioactive isotope to find leaks
• What must the isotope used for leak detection be?

  A gamma emitter with a half-life of several days and not poisonous
• What are the advantages and disadvantages of contamination?

  Advantages:

  • Radioactive isotopes can be used as medical and industrial tracers
  • Use of isotopes with a short half-life limits exposure
  • Imaging processes can replace some invasive surgical procedures

  
  

  Disadvantages:

  • Radioactive isotopes may not go where they are wanted
  • Difficult to ensure full removal of contamination
  • Exposure to radioactive materials can damage healthy cells
• How do irradiation and contamination differ?

  Irradiation:

  • Occurs when an object is exposed to radiation from outside
  • Does not make the object radioactive
  • Can be blocked with shielding
  • Stops when the source is removed

  
  

  Contamination:

  • Occurs if the radioactive source is on or in the object
  • Makes the object radioactive
  • Cannot be blocked once contaminated
  • Difficult to remove all contamination
• What are some effects of radiation on the human body?

  High doses can cause cataracts, cancer, DNA damage, sterility, burns, and leukaemia
• What increases the risk associated with radioactive materials?

  High exposure levels or prolonged exposure to radioactive materials
• What precautions can be taken to reduce the risk of using radioactive sources?

  • Keep radioactive sources shielded when not in use
  • Wear protective clothing
  • Avoid contact with bare skin
  • Wear face masks
  • Limit exposure time
  • Handle materials with tongs
  • Monitor exposure using detector badges
• What is background radiation?

  Low-level radiation exposure from natural and man-made sources
• How does background radiation affect people?

  It mainly affects people through irradiation and a small amount through contamination
• What is the simplest measure of radioactivity?

  The Becquerel (Bq)
• What does one Becquerel (Bq) represent?

  One decay per second from an unstable nucleus
• How does the type of particle emitted affect its impact on the body?

  Alpha particles cause more damage in a shorter distance, while beta particles have less damage due to low ionisation power
• What is the unit used to measure radiation dose?

  The Sievert (Sv)
• How is the Sievert (Sv) related to milliSieverts (mSv)?

  1,000 mSv = 1 Sv
• What is a typical fatal dose of radiation?

  10 Sv
• What is the radiation dose for eating a banana that contains radioactive potassium?

  0.000000098 Sv
• What is the radiation dose for cabin crew on airliners per year?

  0.0016 Sv
• What is the radiation dose for 6 months on the International Space Station?

  0.08 Sv
• What was the highest dose to a worker during the Fukushima disaster?

  0.67 Sv