1. An early x-ray by Wilhem Rontgen
An early x-ray by Wilhem Rontgen
Wikipedia. “ X-Ray.” Wikipedia, pgs Retrieved from:

2. W W F Wavelength x Frequency = Speed of lightW W F
Wavelength x Frequency = Speed of light
Engineering World Health (2015), Great X-Ray Presentation. Retrieved from library.ewh.org

3. Electromagnetic Spectrum
NASA (2007). Electromagnetic Spectrum [image]. Retrieved from

4. Shorter wavelength, higher energy Higher frequency, higher energy
ENERGY
Ability to penetrate
Shorter wavelength, higher energy
Higher frequency, higher energy

5. X-ray Characteristics
X-ray Characteristics
Travel in straight line
Cannot be focused to a point
Differentially absorbed
Cause fluorescence
Harmful to living tissue

6. X-ray Characteristics
X-ray Characteristics
High energy waves
No mass
No charge (neutral)
Travel at speed of light
Invisible

7. X-ray Machine
Tubehead
Support arms
Control panel

8. Strengthening Specialised Clinical Services in the Pacific. User Care of Medical Equipment: A first line maintenance guide for end users. (2015).

9. X-ray Tube
Daniel W. Rickey, Typical Rotating anode X-ray Tube [photograph]. Retrieved from

10. X-ray Tube A- Anode C- Cathode T- Anode Target W- X Ray Window
X-ray Tube
A- Anode
C- Cathode
T- Anode Target
W- X Ray Window
ChumpusRex (2006). Simplified schematic of a x-ray tube in housing [image]. Retrieved from

11. Thermionic Emission
Release of electrons from hot filament when current flows after depressing exposure switch
Deglr6328 (2007), Thermionic filament [photograph]. Retrieved from
The hotter the filament gets, the greater the number of electrons that are released.

12. Anode Dental x-ray machines have stationary anode side view front view
Dental x-ray machines have stationary anode
side view
front view
Target
Copper stem
Target
Engineering World Health (2015), Great X-Ray Presentation. Retrieved from library.ewh.org

13. Medical Radiography Anode (blue edge is tungsten) Filament/
Anode (blue edge is tungsten)
Filament/
Focusing Cup
Electron beam strikes target in this area only
Engineering World Health (2015), Great X-Ray Presentation. Retrieved from library.ewh.org

14. Tungsten (Filament and Target) High atomic number (Z=74)
(Filament and Target)
High atomic number (Z=74)
Transfers heat readily
High melting point (3422º C)
Can be drawn into fine wire

15. Line Focus Principle
The smaller the focal spot (target), the sharper the image (teeth) will be.
During x-ray production, a lot of heat is generated. If the target is too small, it will overheat and burn up.

16. Line Focus Principle PID Target Anode (+) Cathode (-)
Target
Anode
(+)
Cathode
(-)
Apparent (effective)
focal spot size
Actual focal spot size
PID
Engineering World Health (2015), Great X-Ray Presentation. Retrieved from library.ewh.org

17. Line Focus Principle PID Actual focal spot size
Actual focal spot size
(looking perpendicular to the target surface)
Apparent (effective) focal spot size (looking at target surface through PID)
PID
Engineering World Health (2015), Great X-Ray Presentation. Retrieved from library.ewh.org

18. X-ray Machine Components
X-ray Machine Components
X-ray
Tubehead
Control Panel
110, 220 line
Timer
Exposure switch
mA selector
kVp selector
Autotransformer
Step-down transformer
Step-up transformer
X-ray Tube
Wires
Oil
Engineering World Health (2015), Great X-Ray Presentation. Retrieved from library.ewh.org

19. 60-cycle Alternating Current
+ 110, 220
positive
- 110, 220
negative
Direct Current (Constant Potential): 800 cycles/sec.
Engineering World Health (2015), Great X-Ray Presentation. Retrieved from library.ewh.org

20. Number of Impulses Seconds = 60 60 impulses/60 = 1.0 second
1/60
Number of Impulses 60 =
Seconds
60 impulses/60 = second
30 impulses/60 = second
15 impulses/60 = 0.25 second
Engineering World Health (2015), Great X-Ray Presentation. Retrieved from library.ewh.org

21. Exposure Switch
Allows current to flow to complete high and low voltage circuits.
Indicator light and sound
You cannot overexpose by holding
the exposure switch down too long!
Engineering World Health (2015), Great X-Ray Presentation. Retrieved from library.ewh.org

22. milliAmpere (mA) selector
mA setting
OFF 10mA 15mA
milliAmpere (mA) selector
Filament current
Engineering World Health (2015), Great X-Ray Presentation. Retrieved from library.ewh.org

23. Step-Down Transformer
110 volt – 5 volts
Filament Circuit

24. Step-Down Transformer
110 volts
current flow
Primary
3-5 volts
current flow
Secondary
Engineering World Health (2015), Great X-Ray Presentation. Retrieved from library.ewh.org

25. kiloVolt peak (kVp) selector
kVp control
kVp readout
Engineering World Health (2015), Great X-Ray Presentation. Retrieved from library.ewh.org

26. Autotransformer Controls voltage between anode and cathode
Autotransformer
Controls voltage between anode and cathode
Regulated by kVp selector
(Similar to a rheostat)

27. Autotransformer 110 V current flow 65 V 80 V
110 V
current flow
65 V
80 V
Engineering World Health (2015), Great X-Ray Presentation. Retrieved from library.ewh.org

28. Step-Up Transformer 65 - 90 V 65,000 - 90,000 V (65 kVp - 90 kVp)
Step-Up Transformer
V , ,000 V
(65 kVp - 90 kVp)
kVp = kiloVoltage peak

29. Step-Up Transformer Primary Secondary 110 volts 65,000 to 90,000 volts
Step-Up Transformer
110 volts
current flow
Primary
65,000 to
90,000 volts
current flow
Secondary
Engineering World Health (2015), Great X-Ray Presentation. Retrieved from library.ewh.org

30. X-ray Machine Components
oil
exposure
button
filament
filter
Engineering World Health (2015), Great X-Ray Presentation. Retrieved from library.ewh.org

31. kVp 3-5 volts 65-90 volts filament <110 volts 110 volts 65,000 to
kVp
3-5 volts
65-90 volts
filament
<110 volts
110 volts
65,000 to
90,000 volts
Engineering World Health (2015), Great X-Ray Presentation. Retrieved from library.ewh.org

32. X-ray Production 3
Engineering World Health (2015), Great X-Ray Presentation. Retrieved from library.ewh.org

33. Exposure Factors
kVp mA
Exposure time

34. kVp (kiloVolt peak) Number of X-rays X-ray Energy (keV) 90 kVp 70 kVp
90 kVp
Number of X-rays
70 kVp
maximum energy 70 90
average energy
X-ray Energy (keV)
Engineering World Health (2015), Great X-Ray Presentation. Retrieved from library.ewh.org

35. Increasing kVp results in:
Increasing kVp results in:
Higher average energy of x-rays
Greater maximum energy x-rays
More x-rays

36. mA (milliamperes) Number of X-rays X-ray Energy (keV) 10 mA 5 mA
10 mA
Number of X-rays
5 mA
maximum energy
(no change) 70
X-ray Energy (keV)
average energy
(no change)
Engineering World Health (2015), Great X-Ray Presentation. Retrieved from library.ewh.org

37. Exposure time Number of X-rays X-ray Energy (keV) 10 impulses
10 impulses
Number of X-rays
5 impulses
maximum energy
(no change) 70
X-ray Energy (keV)
average energy
(no change)
Engineering World Health (2015), Great X-Ray Presentation. Retrieved from library.ewh.org

38. Increasing mA or Exposure Time results in:
Increasing mA or Exposure Time results in:
An increase in the number of
x-rays produced
No change in the energy of the
x-ray beam

39. mAs or mAi milliamperes (mA) x seconds (s)
milliamperes (mA) x impulses (i)
60 impulses = 1 second
10 mA x .5 seconds = 5 mAs
20 mA x .25 seconds = 5 mAs
mAi = 60 x mAs

40. Collimation Regulates the size and/or shape of the x-ray beam
Regulates the size and/or shape of the x-ray beam
area covered (less patient
exposure)
scatter radiation

41. Scatter Radiation primary x-ray scattered x-ray
primary x-ray
scattered x-ray
Engineering World Health (2015), Great X-Ray Presentation. Retrieved from library.ewh.org

42. Collimation front views side view collimated beam collimator target
front views
side view
collimated
beam
collimator
target
(x-ray source)
2.75 inches (7 cm) = maximum diameter of circular beam or maximum length of long side of rectangular beam at end of PID.
Engineering World Health (2015), Great X-Ray Presentation. Retrieved from library.ewh.org

43. Quality
average energy
Quantity
number of x-rays

44. Inverse Square Law
The intensity of radiation varies inversely as the square of the target-film distance *
* target = source, focal spot, focus

45. Engineering World Health (2015), Great X-Ray Presentation. Retrieved from library.ewh.org

46. Inverse Square Law D D 1 1 100 10 1 100 UI = KI UI 2 X KI = 2
Inverse Square Law D 2 KI
X KI = UI D UI 2 1 1
100 = 10 1
100
X 100 = 1
Engineering World Health (2015), Great X-Ray Presentation. Retrieved from library.ewh.org

47. ?
Questions?