1 dental x-ray machine 118 radiology. 2 the dental x-ray machine consists of 3 visible component...
Post on 16-Dec-2015
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• The Dental x-ray machine consists of 3 visible component parts:– The Control Panel
– The Extension Arm
– The Tubehead
Component Parts
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• The Control Panel contains:– On-off switch and an indicator light– The exposure button and an indicator light– Control devices to regulate the x-ray beam
• Time setting• kVp setting• mA setting
The Control Panel
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Miliamperage and Kilovoltage • Miliamperage = MA• controls number of electrons produced at tungsten filament quantity• 7-15 are average dental x-ray unit mA numbers
• Kilovoltage = kV• controls penetrating power of electrons and x-ray quality• how fast they travel from cathode to anode• creates contrast on resulting film image• usually 70 or 90 kVp kilovoltage power
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Extension Arm
• Hollow, holds electrical wires connecting tubehead with control panel
• Used to position tubehead
• Tubehead attached to arm by yoke, which can be moved 360 degrees horizontally
• Folds up when not in use
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Tubehead
• Houses the x-ray tube
• Made of metal; lined with lead to prevent radiation leakage
• Filled with oil to absorb heat which is generated during x-ray production
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X-ray Tube
• Made of glass• 6” long x 1 ½” diameter• Air is removed to create
vacuum to allow electrons to flow freely between cathode and anode
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Cathode
• Tungsten filament gets hot when electricity is sent to tube
• Creates electron cloud
• Focusing cup: Keeps electrons suspended at cathode
• When exposure button is pushed, electrons shoot across tube to anode
Negative end of tube
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Anode
Postive end of tube• Tunsten target• Electrons strike target and
product x-rays• 99% get absorbed by oil• 1% exits the tube at the area
towards the patient• Center of this beam of x-
rays is called the Central Ray
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PID
• Position indicating device• Lead lined• Aims x-ray beam at film in
pt mouth OR at extra oral cassette
• Open end placed against pt face
• 8,12,16 inches long
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Filter• Aluminum disc at port
where the PID is connected to the Tubehead
• Removes (absorbs) low-energy, long wavelength x-rays
• Only allows high energy, short wave length x-rays to pas through
• Both kinds of x-rays are absorbed by the pt’s tissues; only the short wave length , high energy x-rays create image on film
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