A Positron Emission Tomography(PET) is a nuclear medical imaging technique which produces an image of functional processes in the body.Complete presentation file(PDF) is available for download.
Summary of Positron Emission Tomography (PET):
Positron emission or beta plus decay (+ ) is a particular type of radioactive decay, in which a proton inside a radionuclide nucleus is converted into a neutrino while releasing a positron.Tomography is derived from two Greek words, tome (“cut”) or tomos (“part” or “section”) and graphein (“to write”). Tomography refers to imaging by sections through use of any kind of penetrating waves. PET is based on the annihilation coincidence detection of the two collinear 511-keV -rays resulting from the mutual annihilation of a positron and a negatron, its antiparticle.
- PET scan machine consists of:
(a)Detectors ring (cylindrical, hexagon)
(b) Detectors block each composed of
i. Scintillator crystal
ii. Photomultiplier tubes (PMT’s)
- Approx. 24-32 rings of detector crystals
- Hundred of crystals/ring
Applications of PET:
- Detect cancer.
- Determine effectiveness of treatment such as
- Detect return of a cancer.
- Determine blood flow to heart muscles.
- Determine the effects of heart attack on areas
- To map normal human brain and heart
- Evaluate brain abnormalities; tumors; memory
disorder and other nervous system disorder
Risks of PET:
- Injection of radioisotopes may
cause pain and redness.
- Expensive due to cyclotrons need to produce short-lived
- Low accessibility
- Take time