1. Dental X-ray Machine
118 Radiology

2. Component Parts
The Dental x-ray machine consists of 3 visible component parts:
The Control Panel
The Extension Arm
The Tubehead

3. Control Panels
Older style
Newer Design

4. The Control Panel 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

5. 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

6. Extension Arm

7. 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

8. 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

10. 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

12. Cathode Negative end of tube
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

13. 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

15. 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

16. 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

17. Collimator
Metal disc (lead) with small opening in center to control size and shape of x-ray beam
Further reduces pt exposure
2 ¾” diameter; round shape and size
Also available in rectangular shape which exactly fits #2 film size exposes over ½ less tissue with rectangular collimator