X-Ray machine components Flashcards

1
Q

Electricity

A

power source of x-ray machines

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2
Q

With direct current (DC), electrons flow?

A

In one direction

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3
Q

With alternating current (AC) power, electrons flow?

A

in two directions

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4
Q

Circuit

A

route the electrical current takes

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5
Q

How many volts does a high voltage circuit use to provide high energy to produce x-rays?

A

65,000 to 100,000 volts

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6
Q

Transformer

A

mechanism used in an electrical circuit to increase or decrease the voltage

Can be a step-up, step-down, or autotransformer type

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7
Q

Step-down transformer decreases the voltage from the incoming 110 or 220 volts to ?

A

3-5 volts, needed in the cathode

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8
Q

Control panel

A

Located outside the radiation room

Displays on-off switches and milliamperage/time/kilovoltage settings

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9
Q

Ampere

A

number of electrons per second

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10
Q

An increase in amperage increases?

A

the number of electrons that “work”

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11
Q

How many mAs do dental machines operate with?

A

5-15 mA

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12
Q

Voltage

A

force that moves electrons

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13
Q

KiloVoltage peak (kVp)

A

peak voltage of an alternating current

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14
Q

How much kVp do dental radiographs require?

A

70-90 kVp

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15
Q

kVp determines ?

A

the speed at which the electrons are propelled from the cathode

the penetrating power of the x-ray beam, called quality

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16
Q

Tubehead

A

protective tightly-sealed metal covering (housing)

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17
Q

The tube head contains?

A

X-ray tube, where x-rays are produced

High/low-voltage transformer alters the voltage of incoming electrical current

Insulating oil helps dissipate the heat

Tubehead seal made of leaded glass or aluminum keeps the oil in the tubehead and acts as a filter for x-ray beams

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18
Q

X-ray tube

A

heart of the system

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19
Q

Lead glass vacuum housing

A

Around 6 inches long and 1 inch in diameter. Air was removed to create a vacuum environment that allows the electrons to flow with minimal resistance

Contains two types of electrodes - the cathode and anode

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20
Q

Cathode (negative) electrode

A

supplies electrons that will generate x-rays

Controlled by milliAmperage (mA) settings

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21
Q

Tungsten filament

A

emits electrons when heated, an electron cloud forms around it

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22
Q

Molybdenum cup

A

focusing cup that keeps electrons suspended in an electron cloud

When the exposure button is pressed, the electrons are expelled towards the anode

23
Q

Anode (positive) electrode

A

acts as the target for the electrons

controlled by kVp settings

24
Q

Tungsten target

A

spot where the electrons hit to produce x-rays

25
Q

Focal spot (target)

A

small area on the target on the anode

The electrons from the focusing cup of the cathode are directed towards this target

X-rays originate at the focal spot

26
Q

Copper stem

A

dissipates excessive heat

X-ray production results in the generation of x-rays (1%) and heat (99%)

27
Q

Position-indicating device (PID)

A

open-ended lead-lined cylinder that extends from the opening of the metal housing

it’s all inherent or attached to the x-ray tube head

28
Q

What does the PID attach to and where does it direct the X-ray beams?

A

Attaches to the tube head and directs the x-ray beams to the object and receptor

29
Q

What shape can the PID be in that allows the reduction of exposure?

A

Cylinder or a rectangle

30
Q

Collimators can further restrict the — of the x-ray beam

A

Size

31
Q

Where is the aluminum filter located?

A

inside the PID in the path of the x-ray beam

32
Q

What is the role of the aluminum filter?

A

filters out non-penetrating, long wavelength radiation

33
Q

Where is the open end of the PID placed?

A

against the patient’s face during receptor exposure

34
Q

which PID further restricts scatter radiation? Long or Short

A

a long PID

35
Q

Extension arm

A

Helps in positioning the tubehead - horizontal and vertical movement

Wires that run from the control panel to the tubehead are enclosed within this extension arm

36
Q

When the machine is not in use the extension should be?

A

Folded in order to prevent the arms from becoming “loose,” which will cause drifting of the tubehead

37
Q

where does the PID guide the primary beam of radiation?

A

Towards the patient

The inside is lined with a metallic layer to restrict the primary beams

38
Q

What as the standard lengths of a PID?

A

8 inches and 16 inches

39
Q

What type of rays do long PIDs (16 inches) produce more of?

A

Parallel rays and it reduces radiation exposure

40
Q

Which type of PID reduces radiation exposure the most?

A

Rectangular lead-lined PID

41
Q

Lead apron

A

0.25-3 mm lead shields protect patients from non-productive scatter radiation

42
Q

What should the lead apron cover

A

The patient from the neck and extend over the lap to protect the reproductive areas

43
Q

How should a thyroid collar be placed?

A

thyroid collar should snuggly wrap around the patient’s neck to protect the thyroid glands

*the thyroid gland, particularly in children, is one of the most sensitive organs

44
Q

T/F: the use of lead aprons and thyroid collars for all patients is recommended in the book “Modern Dental Assistant”

A

True

45
Q

Should lead aprons and thyroid collars be folded?

A

No, it could cause cracks; it should be hung up or laid over a rounded surface instead

46
Q

Beam guiding device

A

Helps achieve paralleling technique better

Placed in the patient’s mouth with a portion positioned towards the x-ray tube

Also reduces exposure to the patient’s hand as the tool holds the receptor

47
Q

Filtration

A

Absorbent materials, usually aluminum discs are placed in the path of the x-rays to filter out longer, non-productive wavelengths

48
Q

Inherent filtrations

A

built into the machine and include glass tube, oil, and 0.5-2 mm thick aluminum layer

49
Q

Added filtration

A

depends on the kVp used

  • Below 70 kVp = 1.5 mm thickness of aluminum
  • At and above 70 kVp = 2.5 mm thickness
50
Q

Total filtration

A

sum of inherent and added filtration

51
Q

Collimation

A

Metal barrier (lead diaphragm) with an opening in the middle that restricts the size and shape of the x-ray beam

52
Q

What are the benefits of collimation?

A

Reduces fog, improves image quality, and restricts patient exposure

53
Q

What does rectangular collimation do?

A

restricts the beam to an area slightly larger than a size 2 receptor and creates 60% less radiation exposure compared to a round PID