PET

Question 1

What is PET?

Answer 1

positron emission tomography

Question 2

How does PET work?

Answer 2

When a positron annihilates an electron two gamma photons are produced. A PET scans means an area is enclosed with a ring of gamma detectors. These measure the time delays of when the annihilations took place.
These times can then be used to find the distance along where the annihilations took place. A lot of annihilations in one area suggests a tumour or growth

Question 3

How are positrons added to the patient?

Answer 3

Flourine-18 is injected into the patient since it is a positron emitter. The body has enough electrons within to cause the annihilations.
This is then added to form FDG (glucose) which helps cancers appear since they require a high level of glucose so they show up as hot spots on the scan