brain scans

• PET SCANS:

  Injects radioactive tracer into participant

  the most active areas of the brain use glucose and radiation detectors can ‘see’ the radioactive areas

  builds up a picture of the activity in the brain.
• strengths of PET scans:

  • Take between 10-40 minutes to complete and are painless.
  • Can show the brain ‘in action’
  • Reveal chemical information not available via other scans
  • can differentiate between benign and malignant tumours.
• weaknesses of PET scans:

  • Very costly (£900+) - not easily available for psychological research.
  • injected with radioactive substance - it can only be used a few times.
  • Less precise than MRI
• MRI SCANS:

  • Uses a magnetic field
  • causes the atoms of the brain to change their alignment when on and emit radio signals when off.
  • A detector reads the signals and uses them to map the structure of the brain.
• strengths of MRI scans:

  • Gives a more detailed image of the soft tissue in the brain than CAT scans
  • fMRI measures changes in blood flow = no radioactive substances
  • Both anatomical AND functioning information by taking repeated images of the brain
  • Can have multiple scans as no radiation
  • less harmful
• weaknesses of MRI scans:

  • Take a long time and can be uncomfortable + movement can affect images
  • No cause & effect relationships can be established.
  • costly (£300 - £700)
• CAT SCANS:

  • series of X-rays and combined to form a 2D/3D picture of the area being scanned.
  • Usually a dye is injected into the patient as a contrast material then placed in a cylindrical CAT scan.
• strengths of CAT scans:

  • High quality images
  • Useful for revealing abnormal structures in the brain
• Weaknesses of CAT scans

  • Can only provide structural information
  • Requires more radiation than traditional x-rays