Comparing Imaging Techniques

• What must be balanced against the positive outcomes of imaging scans?

  Potential risks of the scan
• What is necessary for a scan to image the target clearly?

  High enough resolution
• Why is performing an X-ray scan on a foetus considered risky?

  Other scans provide good enough resolution
• When identifying a potential tumour, what is more critical than the risks of the scan?

  High resolution of the scan
• What are the advantages and disadvantages of CT scans?

  Advantages:

  • Show different tissue types
  • High resolution

  
  

  Disadvantages:

  • Expensive
  • Large radiation dose
• What are the advantages and disadvantages of external X-rays?

  Advantages:

  • Cheap, fast, and easy operation
  • High resolution

  
  

  Disadvantages:

  • Cannot distinguish different tissues
  • Cannot image some organs
• What are the advantages and disadvantages of MRI scans?

  Advantages:

  • Distinguish types of tissue
  • No radiation risk

  
  

  Disadvantages:

  • Expensive and time-consuming
  • Uncomfortable for some patients
• What are the advantages and disadvantages of PET scans?

  Advantages:

  • Shows the function of organs
  • Good for imaging the brain

  
  

  Disadvantages:

  • Expensive and time-consuming
  • Does not work for every organ
• What are the advantages and disadvantages of ultrasound scans?

  Advantages:

  • No radiation danger
  • Safe for use on a foetus

  
  

  Disadvantages:

  • Cannot show certain organs (e.g., brain)
  • Lower resolution, hard to operate
• What are the advantages and disadvantages of ingested gamma sources?

  Advantages:

  • Shows function of organs
  • Relatively simple to use

  
  

  Disadvantages:

  • Lowest resolution
  • Radiation risk associated
• Which imaging method is most appropriate for a patient with a lower-body injury?

  External X-ray imaging
• Why is external X-ray imaging appropriate for a lower-body injury?

  It shows potential bone damage quickly
• Why is a CT scan not appropriate for a lower-body injury?

  Higher radiation dose and unnecessary detail
• Why is ultrasound inappropriate for a lower-body injury?

  Real-time scanning is not needed
• Why is gamma imaging inappropriate for a lower-body injury?

  Function of organs is not needed
• What imaging method is best for a patient with a suspected lung tumour?

  CT scan
• Why is a CT scan appropriate for a lung tumour?

  It highlights cancer tissue against healthy tissue
• Why is ultrasound not suitable for imaging a lung tumour?

  Ultrasound is absorbed by air in the lungs
• Why is X-ray scanning not suitable for a lung tumour?

  It may not differentiate tissues well
• Why is an ingested gamma source not suitable for a lung tumour?

  It may not provide a detailed enough image
• What imaging method is appropriate for a patient with a hyperactive thyroid?

  Ingested gamma source
• Why is an ingested gamma source suitable for a hyperactive thyroid?

  It shows the function of tissues
• Why are ultrasound, X-ray, and CT scans not suitable for a hyperactive thyroid?

  They show structures, not function levels
• What should you focus on when comparing imaging techniques in exams?

  • Image resolution
  • Convenience
  • Safety issues