1. 1
   An airline pilot who flies long-haul routes at high altitude for many years is found to receive a higher annual radiation dose than an office worker at sea level, purely from natural background sources.

   (a)

   What is the main reason for this difference?

   [1 mark]

   • AOffice buildings are built from materials that emit no background radiation at all
   • BAircraft engines produce radioactive exhaust gases that increase the pilot's dose
   • CPilots are exposed to radiation from the aircraft's radio and radar equipment
   • DAt higher altitude there is less atmosphere to absorb cosmic rays from space, so exposure to background radiation is greater

   (b)

   Which of the following is an example of a man-made (rather than natural) source contributing to background radiation that a person might be exposed to?

   [1 mark]

   • ACosmic rays arriving from space
   • BFallout from past nuclear weapons testing
   • CRadioactive rocks in the ground
   • DRadon gas released from granite

   (c)

   Explain why the radiation dose a person receives from background radiation depends on both their occupation and their location, giving one example of each.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A hospital uses a radioactive tracer to explore the internal structure of a patient's kidneys, following the tracer's movement through the body using an external detector. In a separate department, the same hospital uses a different, more intense radioactive source aimed carefully at a tumour to destroy cancerous cells.

   (a)

   What is this medical use of nuclear radiation an example of?

   [1 mark]

   • ASterilisation of surgical instruments using nuclear radiation
   • BControl or destruction of unwanted tissue using nuclear radiation
   • CExploration of internal organs using nuclear radiation
   • DSmoke detection using nuclear radiation

   (b)

   In the hospital's separate cancer treatment department, a more intense radioactive source is carefully aimed at a tumour to destroy the cancerous cells. What is this use of nuclear radiation known as?

   [1 mark]

   • ACarbon dating
   • BExploration of internal organs
   • CHousehold smoke detection
   • DControl or destruction of unwanted tissue

   (c)

   Explain why medical staff must carefully evaluate the perceived risks of using nuclear radiation for both diagnosis (the kidney tracer) and treatment (destroying the tumour), even though both uses can benefit the patient.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A local council must decide whether to approve a new medical isotope facility close to a residential area. Residents are worried about the hazards of the radioactive sources that will be stored there.

   (a)

   Explain why the hazard associated with a radioactive source depends on the half-life of the isotope involved.

   [3 marks]

   (b)

   Evaluate the perceived risks of approving the medical isotope facility, using the idea that the risks and benefits of using nuclear radiation must be judged in context. Include a discussion of how the facility's precautions can reduce the actual risk to residents.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A government health agency is reviewing safety guidance for workers in the nuclear medicine industry.

   (a)

   Explain the difference between radioactive contamination and irradiation, and discuss the precautions that should be taken to protect workers from each type of hazard.

   [6 marks]

   (b)

   The agency must also communicate to the public why some uses of nuclear radiation are considered acceptable despite the known hazards. Discuss how the benefits and risks of medical uses of nuclear radiation should be balanced, using the examples of diagnostic imaging and cancer treatment.

   [6 marks]

   Total for question 4: 12 marks

End of questions