Quick facts about PET scans and image acquisition!
Fun fact(s) from today that I learned about PET Imaging (in bullet point format!). This will be a quick one!
1. At the core, a PET (positron emission tomography) scan is used to detect emitted gamma rays from radioisotope labeled molecules introduced into the body.
2. Gamma rays are emitted when an electron and a positron collide with one another. During this collision, the electron and positron are annihilated, and 2 gamma rays are emitted.
3. A positron is a positively charged particle with the same mass as an electron. Positrons are emitted from nuclei containing too many protons (11 C, for example).
4. Other examples of radioisotopes that have too many protons are 13N, 15O, and 18F. These can all be used for PET imaging.
5. Positrons are emitted spontaneously from these radioisotopes so that the nuclei become stable. Emitted positrons eventually come in contact with electrons (See point 2).
6. An example: Cancer cells 'love' glucose. So we can use a labeled glucose analog to visualize tumor cells. 18F fluorodeoxyglucose (FDG) is a 18F labeled glucose analog used for PET imaging.
7. Below is an example of a F18 FDG PET scan. Small black areas are metastasized tumors. The brain uses a lot of glucose, so it also shows as black. Additionally, FDG is filtered by kidneys into the bladder, so these areas are black as well.
8. PET scans are often combined with CT (PET/CT) so that additional information is gained about the anatomy surrounding the tumor. This can help with determining specifics for treatment options or surgery.
See the following for further information:
The video that inspired this blog: https://www.youtube.com/watch?v=l2OVu-JSU2Y