PET Scanning

This lesson covers:

  1. What Positron Emission Tomography (PET) scanning is
  2. Why the isotopes used in PET scans must be produced nearby

PET scans

Positron emission tomography (PET) is a medical imaging technique that uses radioactive isotopes to visualise organ function and diagnose medical conditions. 

How PET scans work


  1. Radioactive isotopes, known as a tracers, are injected into the patient's bloodstream.
  2. The tracers spread throughout the body and emits gamma radiation. Most of the tracers will go to the sites in the body that are most metabolically active (as they will have the best blood supply).  
  3. The patient will lie in a PET scanner which will detect where the gamma radiation is being emitted from.
  4. By seeing where most of the gamma radiation is being emitted from, the doctors can see where the tracers are concentrated, and use this to diagnose medical conditions. 

The tracers must to be made nearby


The radioactive isotopes used in the tracers have short half-lives (to minimise harm to the patient).


This means that they have to be made near the hospital as otherwise they would decay before they can be used. Some hospitals have their own cyclotrons to make their own tracers. 

What does PET stand for?


positron
emission
tomography

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3

What is another name for the radioactive material that is injected into the patient before a PET scan?

Drug

Source

Tracer

Emitter

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What type of radiation is detected in PET scans?

Gamma

Beta

Alpha

X-rays

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