Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

135 Dental Radiography > X-Ray Machine > Flashcards

X-Ray Machine Flashcards

1
Q

What are the 3 parts that compose the x-ray machine?

A

Tubehead
Control Panel
Arm of the machine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the two types of elecric current

A

Direct current and alternating current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is direct current?

A

DC

Current flows in only one direction in an electric circuit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is alternating current?

A

AC

Current flows in one direction and then flows in the opposite direction in the circuit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a cycle (in AC)?

A

refers to the flow of current in one direction, then the reversal, and flowing of the current in the opposite direction

60 cycles/sec

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is voltage?

A

Describes the electric potential or force that drives an electric current through a circuit

Volt= the unit of measurement
kVp= max peak or voltage in AC
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is amperage?

A

amount or quantity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is an ampere?

A

Measures the amount of current flowing through a circuit

Milliampere (mA)= 1/1000 of an ampere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is a transformer?

A

Regulates voltage. Can increase or decrease the voltage in an electric current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is a step up transformer

A

when the transformer increases the voltage (from 110/220 to 65,000-100,000)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a step down transformer?

A

When the transformer decreases the voltage (from 110/220 to 3-5v)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does an autotransformer do?

A

Serves as a voltage compensator that corrects minor fluctuations in the current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a coolidge tube used for?

A

Thermionic emission tube invented by Dr. W.D. Coolidge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

3 Basic elements of an x-ray tube used to produce x-rays

A
  • Source of electrons within the tube
  • High voltage potential to accelerate electrons across the tube
  • Target to stop the electrons
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the 2 sides of the x-ray tube?

A

Negative side= cathode
Positive side= anode

Current flows from cathode to anode

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Devices on control panel for regulating the x-ray beam

A

On/off switch
Activating button
Regulating devices- kVp regulator, mA regulator, timer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the main source of electrons in the x-ray tube?

A

Tungsten filament found at the cathode

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

As the filament becomes hotter, what is happening?

A

More electrons are being produced at the cathode

Emits electrons at a rate proportional to the temperature of the filament

19
Q

What is Thermionic Emission Effect?

A

Production, or boiling off, of electrons from the heated tungsten filament

20
Q

How big is the tungsten filament? How is it mounted?

A

2mm in diameter, 1cm or less in length.

Mounted on 2 stiff wires

21
Q

What does the milliamperage dial do?

A

Controls the amount of current in the filament circuit and the number of electrons that boil off

22
Q

What is the molybdenum focusing cup?

A

Negatively charged, concave reflector that surrounds the tungsten filament and directs electrons towards the anode that contains the target

Parabolic shape. Electrostatically focuses the electrons into a narrow beam

23
Q

What is the tungsten target/focal spot?

A

Small rectangular area on the anode.

Electrons move in this direction and are repelled by the negatively charged cathode and attracted to the positively charged anode

24
Q

Characteristics of tungsten

A

High atomic number
High melting point
Low vapor pressure

Does not have a high degree of thermal conductivity– embedded in a copper stem to carry the heat generated away to the cooling system

25
Q

What does the on/off switch do?

A

Completes the filament circuit

Heats tungsten filament

26
Q

What do the milliamperage settings do?

A

Low voltage current, controls the number of electrons (quantity)
Controls temperature of the tungsten coil
the higher the mA, the hotter the coil; the greater the # of electrons produced in the cloud to be propelled to the target

27
Q

What does the kVp setting do?

A

High voltage current, regulates the speed of the electrons (quality) traveling from the tungsten coil to the target
The higher the kVp, the faster the electrons will travel

28
Q

What is the exposure time of one impulse?

A

1/60 of a second

29
Q

What creates the formation of electron cloud at the cathode as filament circuit is activated?

A

X-ray tube

30
Q

What is the electron cloud?

A

The electrons that stay at the filament

31
Q

What is the cathode ray?

A

Stream of electrons crossing the tube from the cathode to the anode

32
Q

What are soft x-rays?

A

lower energy or less penetrating x-rays

Do not penetrate tissue; produce secondary radiation

Filtered out before they leave the tube

33
Q

What is used in the tube head for filtration?

A

An aluminum disc placed below the porte

2.5mm thick

34
Q

What is collimation?

A

The x-ray beam is limited before it leaves the tube head

Diameter of the beam is limited by a lead diaphragm

Opening is 2.75” and collimator is placed below the aluminum disk

35
Q

What is the central ray?

A

x-rays located at the center of the divergent beam

36
Q

What is penumbra?

A

That part of a shadow of an object which is larger than a point and yet represents a single point on the object

Area of partial shadow
The unsharpness of the image

37
Q

What is umbra?

A

Area of total shadow

38
Q

What is the ideal kVp for viewing carious lesions?

A

65-70 kVp

Higher than this results in an image with a broad scale of contrast making viewing caries more difficult

39
Q

What is density?

A

The degree of blacking on an xray image

Controlled by milliamperage and exposure time

40
Q

What is contrast?

A

The difference in densities between adjacent areas

Primary controlling factor for contrast is kVp. High or low contrast images can be produced

41
Q

Properties of a high contrast image

A

Great deal of black and white with little gray

Produced by low kilovoltage- 45-50kVp range

42
Q

Properties of low contrast image

A

Also referred to as long scale contrast
High kilovoltage range 90-100 kVp
Many tones of gray in addition to whites and blacks

43
Q

What is fogging?

A

Overall grayness on a radiograph resulting from secondary radiation

135 Dental Radiography (23 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions