Gamma Camera Technology BY M.E.THIRUMURUGAN BSC(AHS) SRMC

Gamma Camera Developed by Hal Anger in 1957 therefore also called Anger camera An electronic device that detects gamma rays emitted by radio pharmaceautical (e.g technetium 99 m) that have been introduced into body as tracers. The position of the source of the radioactivity can be plotted and displayed on a tv monitor

Gamma Camera Is a device used to image gamma radiation radioisotopes this technique is called also scintillation camera. Gamma camera is used to view and analyse images of the human body or the distribution of the medically ingested, injected or inhaled radionuclides. Specific Feature: scan whole body anterior and posterior view simultaneous

Gamma Camera

Gamma Camera Components Collimator Crystal Photo multiplier tubes Other circuits Gantry

Gamma Camera Components COLLIMATOR: It is made from lead Maintains the quality of image Spaces between holes is called septa Collimator constists of a series of holes in a lead plate can be used to select the direction of rays failing on the crystal The collimator provides an interface between the patient and the scintillation crystal by allowing only those photons traveling in an appropriate direction.

Collimators

Collimators Types of collimators: A) By the accepted energy. B) By the geometric shape. C) By the resolution.

High Energy Collimator Medium Energy Collimator Collimators By the accepted energy Low Energy CollimatoR High Energy Collimator Medium Energy Collimator

Converging collimator Collimators By the geometric shape. Diverging collimator Parallel-Hole Pin-Hole Collimator Converging collimator

Collimators Pin-Hole (more resolution & magnification) hip,thyroid Parallel-Hole Diverging Converging

Crystal Any damage to the crystal results in an inoperable scintillation camera and requires costly replacement of the crystal. The large surface area, as well as the hygroscopic and brittle nature of the crystal, calls for constant care to avoid puncturing the housing or otherwise damaging the crystal.

Crystal The chosen material for the crystal is sodium iodide with thallium. The Na-I (Tl) crystal is stationary. The crystal transform the gamma-ray photon ------> Light photon

Photomultiplier tube Dynode Connected to High positive volt Photocathode

Photomultiplier tube The Photocathode transform the light photon --- electron. The PMT multiplies the electron to be a significant detected signal.

Other circuits 1)Pre-Amplefier 2) Amplifier

Advantages of Gamma Camera The imaging time is only 1-2min Relatively inexpensive Cheaper than CT or MRI

Disadvantage of Gamma Camera Radiation exposure Contrast materials sometimes used might produce an allergic reaction