8/20: Production of X-Rays Flashcards
1
Q
- What are the numbers listed on the X-ray machine?
A
a. Exposure time
b. kVp
c. mA selectors
d. Exposure button
e. Indicator light and audible signal
2
Q
- What are the parts of the X-ray machine?
A
a. Control panel
b. Tube head
c. Extension arm
3
Q
- What is the tube head composed of?
A
a. Power supply + x-ray tube
4
Q
- Is the cathode or anode associated with the step-down transformer?
A
Cathode
5
Q
- Is the cathode or anode associated with the step-up transformer?
A
Anode
6
Q
- What liquid surrounds the cathode and anode?
A
a. Insulating oil
7
Q
- The x-ray beam must pass through what?
A
a. Aluminum filter
8
Q
- What 2 things are in a cathode?
A
a. Filament
b. Focusing cup
9
Q
- What is the cathode filament made of?
A
a. Tungsten
10
Q
- What is the source of the electrons in the cathode?
A
a. filament
11
Q
- The filament in the cathode emits what?
A
a. Electrons
12
Q
- The cathode is heated with a low voltage source and emits electrons at a rate proportional to its temperature. This is known as (step-down transformer will control heat!!!!!!!!!)
A
a. Thermionic emission
13
Q
- What is the cathode focusing cup composed of?
A
a. Molybdenum
14
Q
- What is true regarding the step-down transformer?
A
a. Controls heat to cathode (thermionic emission)
15
Q
- The focusing cusp focuses the electrons into a
A
a. Focal spot
16
Q
- Is the cathode positive or negative?
A
Negative
17
Q
- Is the anode positive or negative?
A
Positive
18
Q
- What 2 things make up the anode?
A
a. Tungsten target
b. Copper stem
19
Q
- The focal spot is located on the
A
a. Tungsten target of the anode
20
Q
- Where do the electrons hit
A
a. Tungsten target on the anode
21
Q
- This transforms the kinetic energy of the colliding electrons into x-ray photons
A
a. Tungsten target
22
Q
- What occurs at the tungsten target?
A
a. Produces X-rays
23
Q
- Is the tungsten target efficient or inefficient?
A
a. Inefficient 99%, 1% efficient
24
Q
- The tungsten target is attached to what part of the anode?
A
a. Copper stem
25
25. This works as a thermal conductor to remove the heat from the tungsten avoiding target melting
a. Copper stem
26
26. Why is tungsten a good target material?
a. High atomic number
b. High melting point
c. High thermal conductivity
d. Low vapor pressure
27
27. What are the conditions necessary for X-ray production?
a. Separation of electrons
b. Production of high-speed electrons
c. Concentration of electrons
d. Sudden stoppage of electron steam
28
28. Does having a higher atomic number help with efficient production of X-rays
Yes
29
29. Separation of electrons is called
a. Thermionic emission (in the cathode filament)
30
30. High potential difference is produced between the cathode and anode by applying what
a. High voltage between them
31
31. To what speed are electrons accelerated?
a. 0.5x speed of light
32
32. What does the copper stem do to the tungsten?
a. Remove the heat because it is an inefficient process
33
33. Do you want a bigger or smaller focal spot?
a. Smaller
34
34. Why is size important for the focal spot?
a. The smaller = higher spatial resolution
35
35. The smaller the focal spot, the heat _____
a. Accumulates
36
36. When the focal spot is smaller, you get more heat accumulation. What 2 ways can you overcome this problem?
a. Rotating anodes
b. Stationary anodes
37
37. Stationary anodes are also known as what principle?
a. Line-focus principle
38
38. This allows heat at the focal spot to spread out over a large surface
a. Rotating anode
39
39. Rotating anodes can be identified by
a. Dark band
40
40. Rotating anodes are used in
a. Medical devices
41
41. This is when you angle the target to achieve a smaller effective focal spot than the actual focal spot
a. Line-focus principle (stationary anode)
42
42. The projection of the focal spot perpendicular to the target
a. Actual focal spot
43
43. the projection of the focal spot perpendicular to the electron beam
a. Effective focal spot
44
44. What is true of Stationary anode (life-focus principle)?
a. The effective focal spot is smaller and has sharper resolution
45
45. In the line-focus principle, what is smaller?
a. Effective focal spot
46
46. This provides a low-voltage current to heat the x-ray tube filament
a. Step-down transformer
47
47. This generates a high potential difference to accelerate electrons from the cathode to the anode
a. Step-up transformer
48
48. This is a electromagnetic device that either increases or decrease the voltage on a circuit
a. Transformer
49
49. What are the 3 types of transformers in an X-ray device?
a. Step-down
b. Step-up
c. Autotransformer
50
50. This is a filament transformer
a. Filament transformer
51
51. This is a high voltage transformer
a. Step-up
52
52. The step-down transformer is regulated by
a. mA switch
53
53. The step-up transformer is regulated by
a. kV setting
54
54. Increasing the number of electrons emitted
a. Increasing mA
55
55. Increasing the energy of the electrons traveling from the cathode to anode
a. Increasing kV
56
56. kV is associated with what?
a. High voltage, step-up transformer
57
57. mA is associated with what?
a. Low voltage, step-down transformer
58
58. This determines the amount of time the high voltage circuit is applied across the x-ray tube
a. Exposure time
59
59. This is the delay of 1⁄2 of a second to heat the filament
a. Time delay circuit
60
60. This is the actual time of exposure
a. Timing circuit
61
61. Few coils to many coils =
a. Step-up transformer
62
62. Many coils to few coils =
a. Step-down transformer
63
63. Low-voltage =
a. Step-down
64
64. High voltage =
a. Step-up
65
65. This controls the acceleration of electrons from the cathode to the anode
a. kV (kilovoltage)
66
66. This controls heating of the filament
a. mA (milliamperage)
67
67. This controls the time in which x-rays are produced
a. Exposure time
