Uses of Radioactive Material (WJEC GCSE Physics: Combined Science)

Medical Tracers

• A tracer is a radioactive isotope that can be used to track the movement of substances, like blood, around the body
• Gamma emitters are usually used for this purpose
  • Gamma rays are highly penetrating and so will be able to pass through the body and be detected outside the body

• This allows an internal image of the body to be created

Using a Radioactive Isotope as a Tracer

Iodine-131 is an example of a radioactive tracer

• Since gamma rays are less ionising than some other forms of radiation, the harm caused to the patient is also minimised
• As well as choosing a gamma emitter:
  • The amount of isotope used is kept to a minimum to reduce people’s exposure to radiation
  • Isotopes are chosen that have short half-lives of around a few hours: Long enough to carry out the procedure, but not so long that they cause long term harm

Radiotherapy

• Radiotherapy is the name given to the treatment of cancer using radiation
• Although radiation can cause cancer, it is also highly effective at treating it
• Radiation can kill living cells
  • Some cells, such as bacteria and cancer cells, are more susceptible to radiation than others

• During external radiotherapy, beams of gamma rays are directed at the cancerous tumour
  • Surrounding healthy tissue tends to be shielded to avoid causing any damage

Radiotherapy Treatment

During radiotherapy, the beams are moved around to minimise harm to healthy tissue whilst still being aimed at the tumour

• During internal radiotherapy, small pellets of radioactive materials can also be inserted into a tumour exposing it directly to radiation

Sterilising Medical Equipment

• Gamma radiation is widely used to sterilise medical equipment
• Gamma is most suited to this because:
  • It is the most penetrating out of all the types of radiation
  • It is penetrating enough to irradiate all sides of the instruments
  • Instruments can be sterilised without removing the packaging