What is the use of fluorine-18 in a PET scan?
In: Chemistry
Fluorine 18 is a radioactive isotope that emits an positron (anti-electron). That positrons annihilates with nearby electrons and e,it’s two gamma energy photons) back to back. Detectors set around the patient detect those gamma rays and thus give a line in space along which the f18 was initially located.
After many decays you get many lines in space so you get a map of intersecting lines, the areas where many lines interest are those with a high concentration of the fluorine. Since the molecule the fluorine is attached to is a sugar molecule it get carried by the blood stream to areas which take a lot of blood, like tumors, this lets the doctor figure out where the likely tumors are.
In short, the fluorine 18 is a marker for those areas of high blood requirements.
PET (Positron Emission Topography) scans are watching for the results of a positron meeting and electron and shooting two gamma rays out in each direction.
Flourine-18 is handy because when it decays it releases a positron instead of an electron like most things and swaps one of its protons for a neutron to make it Oxygen-18.
When this emitted positron encounters an electron, they’ll merge and become pure energy which is generally in the form of a pair of gamma rays. By detecting these rays and determining where in your body they came from, they can see where the flourine-18 tracer went which tells them about blood flow and metabolic processes.
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