Positron Emission Tomography (PET)

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.

positron emission tomography(PET)

positron emission tomography(PET)


  • PET scan machine consists of:
    Positron camera
    (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
    cancer therapy.
  • Detect return of a cancer.
  • Determine blood flow to heart muscles.
  • Determine the effects of heart attack on areas
    of hearts.
  • 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

Download PDF File Here:

  1. Positron Emission Tomography (PET)

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