By: a guest on Jul 17th, 2012
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Positron Emission Tomography detects photon pairs which are created when electrons from the body encounter positrons from an injection of the radioactive substance caked flurodeoxyglucose (FDG, which is a sugar with the radioactive fluorine-18 attached to it). The positrons are released when the radioactive fluorine decays. However different radioactive medicines may be used and attached to other natural substances such as ammonia or water depending on what needs to be detected.
PET scanners are used to understand what is happening metabolically in the body, rather than being able to view certain parts of the body. They produce 3D colour images. The photon pairs produce and image which will show where the photons (radioactive glucose) have been transported around the body, which detects problems that may be causing the radioactive glucose to either be blocked from going to certain areas, or may be causing it do go areas where it shouldn’t.
While the gamma rays (also known as photons) are incredibly dangerous, they are only injected in small amounts and are transport and remove themselves from the body quickly, therefore are not dangerous towards patients.
They are used to detect cancers in the body and to detect the effects of cancer treatment and also for heart disease and tumours in the brain. Cancers can be detected as they use glucose differently from normal body tissue, therefore showing up differently in the scan.