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ULSD ORAD I - 2024 > X-ray Units > Flashcards

X-ray Units Flashcards

1
Q

Tungsten has a ______ atomic number which helps with an efficient production of x-rays.

A

High

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2
Q

What is amperage?

A

Number of electrons moving through a circuit

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3
Q

What is voltage?

A

Electrical force that causes electrons to move from a negative pole to a positive pole.

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4
Q

What are three things to know about the tungsten filament?

A
  • Source of electrons (electric current)
  • Highest tensile strength of any pure metal
  • Highest melting point of any pure metal
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5
Q

When will X-rays be produced?

A

When electrons inside the tube start to accelerate and then collide against a target, thus turning the kinetic energy of the electrons into X-rays

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6
Q

What term? Electrical force that causes electrons to move from a negative pole to a positive pole

A

Voltage

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7
Q

What Term? Number of electrons moving through a conductor

A

Amperage

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8
Q

What is the source of electron from the cathode?

A

Tungsten filament

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9
Q

What is the target of the anode?

A

Tungsten block

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10
Q

Fill in the blank:
The _____ _____ is the part of the unit where x-rays will be produced

A

X-ray tube

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11
Q

Which of the following is not a component of an intraoral unit?
A: tube head
B: extension arm
C: C-Arm
D: control panel

A

C: C-Arm
(component of extraoral units)

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12
Q

What is the function of the collimator?

A

To define the shape and size of the X-ray beam

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13
Q

What is the downside of using portable X-ray units?

A

Longer exposure times to radiation.
Higher risk of exposure of the operator to scattered radiation.

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14
Q

Name the 3 main components of an intraoral x-ray unit

A

1) tube head
2) extension arm
3) control panel

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15
Q

Why do we use tungsten filament in a X-ray tube?
A. It has a high source of electrons.
B. It has high tensile strength.
C. It has a high melting point.
D. All of the above

A

D. All of the above

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16
Q

What are the two main functions of insulating oil?

A

1) Heat convection
2) Electric insulator

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17
Q

X rays will be produced when _______ inside the tube start to accelerate and then collide against a target, turning the kinetic energy of the ______ into x-rays.

A

electrons, electrons

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18
Q

What factors improve the quality of an X-ray?

A

Increased voltage –> Increased electron acceleration –> Increased kinetic energy

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19
Q

What are the different shapes (collimations) for X-ray beams?

A

Cylindrical and rectangular

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20
Q

Increasing the ________ will increase the amount of x-rays produced by a unit.

A

Electrical current or milliamperage

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21
Q

Increasing ________ will increase the mean energy of x-ray photons.

A

Voltage or kV

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22
Q

Compare and contrast the 2 collimator types used in modern dentistry.

A

Rectangular collimators are better at reducing patient and secondary radiation exposure. Rectangular collimators also reduce fog on the image due to less scattered radiation reaching the sensor, which may improve the image quality.

Round collimators result in less technique errors by radiating a larger area, allowing for more human error with sensor placement.

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23
Q

What are the three parts of the X-ray tube?

A

cathode, anode, and evacuated lead glass envelope

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24
Q

What is activated when pushing the exposure button on the x-ray machine?

A

High voltage transformer

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25
Q

What is the low-voltage transformer connected to?

A

The cathode only

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26
Q

What is the collimator made of and what does it do?

A

Lead disc, blocks more divergent photons, collimates the beam area

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27
Q

Which voltage transformer (low or high) is connected to the anode and cathode?

A

high voltage transformer

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28
Q

Why is the cathode a negative electrode?

A

That’s where the e- are before acceleration (before pressing the exposure button)

29
Q

What is the importance of having a lower voltage at the low voltage transformer?

A

To decrease the speed of the electrons in the tungsten filament so it can increase the number of electrons (amperage) before accelerating to the anode

30
Q

What kind of movements does the extension arm make?

A

Horizontal and Vertical

31
Q

T/F : Increase in applied voltage will decrease the electron acceleration and increase kinetic energy.

A

False

32
Q

T/F: Decrease in Focal Spot size will increase divergent rays

A

False

33
Q

What defines the voltage to the High-Voltage Transformer?

A

An Autotransformer
(by adjusting the kVp in the unit’s control panel)

34
Q

What does the tube head consist of?

A

X-ray tube
Low-voltage / filament transformer
High-voltage transformer
Insulating oil
Metal housing - lead coating
Aluminum filter
Collimator
Position-indicating device (PID)

35
Q

What is the most important component for heat dissipation?
What is the second most important component for heat dissipation?

A

1st = Copper block
2nd = Insulating oil

36
Q

What are examples of inherent filtration?

A

Insulating oil and X-ray tube glass

37
Q

What is the difference between filtration and collimation?

A

Collimation allows a shape of the beam through, blocking the other divergent photons
Filtration has no opening and only allows high energy beams through, filtering out the lower energy photons

38
Q

What is the material surrounding the focal point made of that helps with heat dissipation?

A

Copper

39
Q

What material is the additional filter made of?

A

Aluminum

40
Q

What are the two types of x-ray units?

A

-intraoral
-extraoral

41
Q

What happens as a result of an increase in the amperage of the cathode?

A

This leads to an increase of the temperature of the filament and the number of electrons in the electric current, increasing the electron cloud around the filament.

42
Q

T/F: The function of the molybdenum cup is for electric insulation of the tube head.

A

F: The molybdenum cup’s function is to help focus the electrons so they travel directly from the cathode to the anode (target).

The insulating oil is for electric insulation of the tube head.

43
Q

What has the highest melting point of any pure metal?

a) Iron
b) gold
c) tungsten
d) titanium

A

c) tungsten

44
Q

Which of the following is not a component of the tube head of an x-ray unit?
a) insulating oil
b) collimator
c) exposure button
d) position-indicating device

A

c) exposure button (part of the control panel)

45
Q

What is the focusing cup of the cathode made of?
a) tungsten
b) aluminum
c) copper
d) molybdenum

A

d) molybdenum

46
Q

What percentage of the electrons’ kinetic energy in X-ray production leaves as X-ray photons?

A

1% or less

47
Q

If you increase mA (electrical current), do you increase or decrease amount of X-rays produced?

A

Increase

48
Q

T/F: The extension arm does only horizontal movements.

A

FALSE. The extension arm can do vertical and horizontal movements.

49
Q

Why should the x-ray tube head be pointed away from the patient when not in use?

A

Just in case there is a malfunction in the x-ray unit to avoid hot insulating oil getting onto the patient (highly unlikely to happen; but still should take precautions)

50
Q

T/F Collimation is the same as filtration?

A

False

51
Q

What is the thickness of the Aluminum filter of the tube head?

A

0.5 - 3mm

52
Q

Total filtration of the tube head is the combination of:

A

inherent filtration and additional filtration

53
Q

What is the difference between the blocks used for the Target and Heat Dissipation?

A

Target uses a Tungsten block. Tungsten has a high melting point, and a high atomic number with more electrons in the orbitals - is the site where X-rays are being generated.

Heat Dissipation uses a Copper block. Copper is very effective at dissipating the heat generated during X-ray production.

54
Q

What is the most commonly used anode in dental units?

A

Most commonly used: Stationary anode

Least commonly used: Rotating anode

55
Q

Which of the following is the correct degree for an anode angle?
A. 15
B. 20
C. 25
D. 37

A

D. 20 degree

56
Q

What is the correct heat dissipation in a tube head?

A

Heated tungsten block -> Copper block -> Insulating oil

57
Q

What type of collimator in the tube head may result in unnecessary additional x-ray exposure to the patient?

A

Round

58
Q

If you increase the voltage applied (kV), what happens to electron acceleration and kinetic energy?

A

They both increase

59
Q

What does an autotransformer do?

A
  • Defines the voltage to the High-Voltage Transformer
  • kV selector
  • Stabilized and ideal voltage
60
Q

Lead disc that blocks the more divergent photons

A

Collimator

61
Q

What are the three ways an intraoral X-Ray unit can be installed?

A
  • fixed to the wall
  • on a mobile stand
  • portable
62
Q

What is the PID of an intraoral X-ray unit?

A

Position indicating device
(aiming cylinder that will assist aligning the x-ray photons to the area to be exposed)

63
Q

(T/F) In X-ray production, electron acceleration is from cathode to anode

A

True

64
Q

The control panel of the x-ray unit includes:

A. Exposure button
B. Indicator Light
C. Anatomical regions preset
D. All above answers are correct

A

D. All above answers are correct

65
Q

What percent of energy in X-ray production is given off as heat?

A

99% or more

66
Q

Only with the use of this type of x-ray unit a clinician may stand directly beside the patient during x-ray production.

A

Portable x-ray unit.

67
Q

What settings on the unit’s control panel can be changed?

A
  • Exposure time
  • Kilovoltage
  • Milliamperage

As well as presets for anatomical regions and adult/children settings.

68
Q

What charge does an anode have?

A

a positive electrode (+)

ULSD ORAD I - 2024 (8 decks)

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