presentation contain information about gamma camera machine, how works the machine,what are the components and its working

1. Muhammad Musaddiq

2. GAMMA CAMERA Dual Head Gamma Camera Manufacturer: Toshiba Model: GCA-7200A Department: Nuclear Medicine. Specific feature is Scan whole body anterior and posterior view simultaneously.

3. GAMMA CAMERA Developed by Hal Anger at Berkeley in 1957 therefore also called Anger camera An electronic device that detects gamma rays emitted by radio pharmaceautical (e.gtechnetium 99m (Tc-99m)that have been introduced into the body as tracers. The position of the source of the radioactivity can be plotted and displayed on a TV monitor or photographic film.

4. COMPONENTS OF GAMMA CAMERA Collimator NaI(Tl) crystal. Photomultiplier Tubes(PMT) Pre-amplifier Position logic circuits Amplifier Pulse height analyzer Data Analysis Computer Display (Cathode Ray Tube etc). Gantry

5. FLOW DIAGRAM OF GAMMA CAMERA

6. COLLIMATOR Collimator is made from lead. Maintains the quality of image Spaces between holes known as septa Collimator consisting of a series of holes in a lead plate can be used to select the direction of the rays falling on the crystal. There are 4 types of collimator. Parallel-hole collimator Pin-hole collimator Diverging Converging Most collimators in use are parallel hole collimators. A parallel hole collimator is shown schematically in Figure.

7. COLLIMATOR(cont)

8. SCINTILLATOR (CRYSTAL) Sodium iodide with thallium NaI( Tl ) The main function of crystal is convert gamma ray to photons of visible light process called scintillation. Amount of light proportional to deposited energy.

9. CRYSTAL (cont)

11. Gamma Camera contains 37 -91 PMT.

13. PRE AMPLIFIER AND AMPLIFIER Preamps attach above the PMT. The amount of charge given by PMT is very small. Even though we have used a sophisticated photodetector like a PMT we still end up with quite a small electrical signal. A very sensitive amplifier is therefore needed to amplify this signal. This type of amplifier is generally called a pre-amplifier. Afte that use amlifier to amlify the signal as need.

14. POSITION CIRCUITARY & PULSE HEIGHT ANALYSER Position circuitary receive the electrical impulses from the tubes in the summing matrix circuit (SMC). This allows the position circuits to determine where each scintillation event occurred in the detector crystal. The amplitude of each electrical pulse from the amplifiers is measured in the electrical circuits of the pulse-height analyzer Peak height analyzer and a computer convert the light into a useful anatomical image

15. DATA ANALYSIS COMPUTER Finally, a processing computer is used to deal with the incoming projection data and processes it into a readable image of the 3D spatial distribution of activity within the patient. The computer may use various methods to reconstruct an image, such as filtered back projection or iterative reconstruction.

16. GANTRY A gamma camera system attached with gantry. All circuits and motors related to movement ( longitudnal,rotational,up & down)of gamma camera placed in gantry. gantry

17. GAMMA CAMERA SCAN The scan of whole body.

18. APPLICATION OF GAMMA CAMERA GAMMA CAMERA used to locate cancerous tumours,minor bone fractures,abnormal functioning of organs and other medical problems . Iodine-131 is used to detect thyroid (a gland that absorbs Iodine) problems. Technetium-99 is used to find tumours in the body. Gamma camera give structural and functional image of body organs. Bone scan. Myocardial Perfusion Lungs scan. Kidney function. Thyroid uptake Whole body scan.

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