PET scanning (Edexcel GCSE Physics Combined Science): Flashcards
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What does PET stand for?
What does PET stand for?
Positron Emission Tomography
Main use of PET scanning
Main use of PET scanning
See how organs function and diagnose conditions like cancer
What PET scans show
What PET scans show
Areas of high metabolic activity
Why cancer cells show clearly on PET scans
Why cancer cells show clearly on PET scans
Higher metabolism - use more energy than healthy cells
Substance injected in PET scanning
Substance injected in PET scanning
Radioactive substance (tracer) with positron-emitting isotope
Example of tracer used in PET scans
Example of tracer used in PET scans
Glucose containing radioactive isotope
What happens when a positron meets an electron?
What happens when a positron meets an electron?
They annihilate each other
What positron-electron annihilation releases
What positron-electron annihilation releases
Gamma rays in opposite directions
How many gamma ray pairs needed to locate a tumour?
How many gamma ray pairs needed to locate a tumour?
3 pairs
Method to pinpoint tumour location in PET scan
Method to pinpoint tumour location in PET scan
Triangulation
Why are short half-life isotopes used in PET scans?
Why are short half-life isotopes used in PET scans?
Decay quickly, don't stay in body too long
What machine makes isotopes on-site at hospitals?
What machine makes isotopes on-site at hospitals?
Cyclotron
Why isotopes made close to hospital
Why isotopes made close to hospital
Decay fast; activity decreases too much if transported far
Where tracer collects in body
Where tracer collects in body
Areas with high metabolism, such as cancer cells