Brainscape's Knowledge GenomeTM

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


See full index

RT 209 > X-Ray Circuits > Flashcards

X-Ray Circuits Flashcards

1
Q

Three parts of General X-ray Circuit

A
  1. Primary Circuit
  2. Secondary Circuit
  3. Filament Circuit
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

General X-ray Circuit

Main power switch, circuit breakers, the autotransformer, the timer circuit, primary side of the step-up transformer

A

Primary Circuit

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

General X-ray Circuit

Secondary side of the step-up transformer, the milliampere meter, a rectifier bank, and the x-
ray tube (except for the filaments)

A

Secondary Circuit

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

General X-ray Circuit

Rheostat, step-down transformer, the filaments

A

Filament Circuit

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

incorporates a meter to measure the voltage provided to the x-ray machine and a control to adjust that voltage to precisely 220 volts.

A

Line Compensator

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

Included in the primary circuit to protect against short circuits and electric shock

A

Circuit Breakers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Is an adjustable transformer controlled by the kVp selector on the operating console

A

Autotransformer

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

Autotransformer

An autotransformer operates in the principle of?

A

self-induction

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

Autotransformer

When a radiographer selects a ——, he or she determines the number of turns on the —— to be included in the circuit element and with it the output voltage.

A
  • kVp setting
  • secondary side
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Autotransformer is sometimes called

A

kVp selector

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

Autotransformer

The primary Purpose is to provide a ——- that will be increased by the ———- to produce the —— selected at the operating console.

A

*a voltage
* step-up transformer
* kilovoltage

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

The radiographer controls the autotransformer through —————–, and through this directly determines the ——- applied to the x-ray tube to produce x-rays.

A
  • the kVp selector on the operating console
  • voltage
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

When a radiographer selects a kVp setting, he or she determines ——— to be included in the circuit element and with it the output voltage.

A

number of turns on the secondary side

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q
  • Used to increase the voltage from the autotransformer to the kilovoltage necessary for x-ray production.
  • Not adjustable and increases the voltage from the autotransformer by a fixed amount.
A

Step-Up Transformer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Consists of mechanical and electronic devices whose action is to “make” and “break” the high voltage across the x-ray tube.

A

Timer Circuit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q
  • Cause the x-ray tube to emit x-rays for a specific time as determined by the radiographer or by AEC.
  • Controls the length of exposure
A

Exposure Timers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q
  • Simple devices use in some portable and dental units
  • Operates by clockwork
  • inexpensive but not very accurate
  • Exposure times greater than 250 ms
A

Mechanical Timers

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

Minimum exposure time possible 1/60 second

A

Synchronous Timer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q
  • Most sophisticated, most complicated, most accurate
  • Used for rapid serial exposures
  • Exposure time as small as 1 ms
  • Wide range of time intervals
  • Based on the time it takes to charge a capacitor through a variable resistor
A

Electronic Timers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

_________ designed for accurate control of tube current and exposure time, Terminates the exposure once desired mAs is attained and is located in _________

A
  1. mAs timers
  2. secondary circuit
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Automatically terminates the exposure when sufficient radiation to provide the required optical density has reached the image receptor.

A

Automatic Exposure control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Device that measures the quantity of radiation reaching the image receptor.

A

Phototimer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Two types of Phototimer

A
  • Photomultiplier tube
  • Ionization chamber
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Method used to check the accuracy of exposure timer

A

Spinning Top Test

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Is a device placed in the secondary circuit that monitors x-ray tube current

A

mA meter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

assembled into electronic circuits to
convert alternating current into the direct current necessary for the operation of an x-ray tube

A

Rectifiers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

is responsible for converting the low voltage from the electric power company into a kilovoltage of proper waveform.

A

High-Voltage Generator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Three primary parts of a High voltage-transformer
(H, F, R)

A
  • High-voltage transformer
  • Filament transformer
  • rectifiers
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Is a step-up transformer. The secondary voltage is greater than the primary voltage because the
number of secondary windings is greater than the number of primary windings.

A

High Voltage-Transformer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

The ratio of the number of secondary windings to the number of primary windings.

A

Turns Ratio

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Sample Problem: Turns Ratio

The turns ratio of a high-voltage transformer is 700:1, and the supply voltage is peaked at 120 volts.

What is the secondary voltage supplied to the x-ray tube?

A

84,000 Vp or 84 kVp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

process of converting alternating voltage to direct voltage and therefor alternating current to
direct current.

A

Rectification

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Property of an x-ray tube which means that it acts as a valve permitting the flow of current in only one
direction, from the cathode to the anode.

A

Self-Rectification

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Represents condition in which the voltage is not allowed to swing negatively during the negative half of its cycle.
* Contain zero, one, or two diode
* X-ray output is pulsating, with 60 x-ray pulses per second

A

Half-Wave Rectification

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

In Half-Wave Rectification:
* Contains how many diodes
* X-ray output is pulsating with ——- ?

A
  • Contains zero, one or two diodes
  • 60 x-ray pulses per second
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

the negative half cycle corresponding to the inverse voltage is reversed so that a positive voltage is always directed across the x-ray tube.

A

Full-wave Rectification/ Full-wave rectified circuit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

In Full-wave Rectification:
* Contains how many diodes
* X-ray output is pulsating with ——- ?

A
  • at least 4 diodes
  • 120 x-ray pulses per second
38
Q
  • Results in pulsating x-ray beam
  • Alternate swing from zero to maximum potential 120 times per second
  • Low energy, low penetrability, low diagnostic value
A

Single-Phase Power

39
Q
  • Generates three simultaneous voltage waveforms out of step with one another.
  • Voltage across x-ray tube is nearly constant and never drops to zero during exposure.
  • Requires additional size and cost
A

Three-Phase Power

40
Q
  • Can be place in the x-ray tube housing
  • Produce nearly constant potential
  • Improves image quality
  • Lower patient dose
A

High-Frequency Generator

41
Q
  • Are high-speed switches, or choppers, that convert DC into a series of square pulses.
  • Used by a high-frequency voltage generation.
A

Inverter Circuits

42
Q

Uses nickel-cadmium (NiCd) battery

A

Capacitor Discharge Generator

43
Q

delivers the maximum possible mA for the selected kVp by considering the instantaneous heat load characteristics of the x-ray tube.

A

Falling-load capability

44
Q

This delivers the desired amount of radiation to the image receptor in the shortest possible exposure time.

A

Falling-load Generator Control Circuit

45
Q

Failing-load Generator Control Circuit

During capacitor , the voltage falls approximately?

A

1 kv/mAs

46
Q

works on the principle that a small current is drawn from the mains to charge a capacitor before the x-ray exposure, and this capactor is allowed to discharge through the x- ray tube during exposure.

A

Capacitor Discharge mobile

47
Q

Is the variation in peak voltage waveform.

A

Voltage Ripple

48
Q

100% voltage ripple
* The voltage varies from zero to its maximum value

A

Single-phase Generator

49
Q

Three-phase Generator

3-phased, 6 pulse generator = ?
3-phased, 12 pulse generator = ?

A
  • 13% voltage ripple
  • 4 % voltage ripple
50
Q

Less than 3% voltage ripple

A

High-Frequency Generator

51
Q

Formula for Power Rating

A

Power = current x potential
Watts = Amperes x volts

52
Q

When specifying high-voltage generators, the industry standard is to use the maximum tube current(mA) possible at 100 kVp for an exposure of 100 ms.

A

Maximum Available Power

53
Q

3 phase generator and high frequency formula for power rating

A

Power Rating = mA x kVp/ 1000

54
Q

Sample Problem: Power Rating

A radiographic single-phased unit installed in a private office has a maximum capacity of 100 ms of 120 kVp and 500 mA. What is its power rating?

A

42 kW

55
Q

A variable resistor controlled by the mA selector on the operating console

A

Rheostat

56
Q

When the radiographer adjusts milliamperage on the operating console, he or she is adjusting this ——- and ultimately the amount of current applied to the filament (filament current) in the x-ray
tube.

A

Rheostat

57
Q

Rheostat

The higher milliamperage station number, the ?

A

the lower resistance

58
Q

The goal of it is to literally boil electrons out of the filament wire.

A

Filament circuit

59
Q

Normally, a rather large filament current of ——— required to produce a tube current in the range of milliamperes.

A

5 to 7 amperes

60
Q

FIlament Circuit

Rheostat controls ?

A

filament temperature

61
Q

Used in filament circuit to increase the current by reducing the voltage that is applied to the filament.

A

Step-down Transformer

62
Q

The purpose is to control the degree and duration that the filament is heated, which in turn controls the number of electrons boiled off that will ultimately become the tube current.

A

Filament Circuit

63
Q

Two kinds of Filaments

A

Small and Large filaments

64
Q

Represented on the operating console by the “large focal spot” and “small focal spot”.

A

Filaments

65
Q

Principles of Circuit Operation

  • The ——- adjusts the autotransformer and determines the number of turns on the secondary side necessary to produce a voltage, through self-induction, that will be sent to the step-up transformer.
  • The ———— increases this voltage by a fixed amount and, through mutual induction, produces the kilovoltage selected on the operating console.
  • This ——- must be rectified.
  • The ——– draws electricity from the autotransformer, which then travels to the rheostat.
  • The ————- sets the resistance in the filament circuit.
  • From the rheostat, electricity travels to the ——.
  • The kilovoltage applied to the x-ray tube creates a ——— on the anode and a ——— on the cathode.
A
  • kVp selected
  • step-up transformer
  • kilovoltage
  • filament circuit
  • selected mA station
  • step-down transforment
  • large positive charge and large negative charge
66
Q

Allows radiographer to control the x-ray tube current and voltage so that the useful x-ray beam is of proper quality and quantity.

A

Operating Console/Control Panel

67
Q

X-ray Quantity and Quality

Refers to the number of x-rays or intensity of the beam usually expressed in mR or mR per
mAs.

A

Quantity

68
Q

X-ray Quantity and Quality

Refers to the penetrating qualities of the x-ray beam and is expressed by kVp or HVL

A

Quality

69
Q

Factors that Affect X-ray Quantity

A
  • mAs
  • kVp
  • Distance
  • Filtration
70
Q

Factors that Affect X-ray Quality

A
  • kVp
  • Filtration
71
Q

Some Basic Controls For Every Panel

A
  • On/off switch
  • mAs selection
  • kVp selection
  • Table or wall unit activation
  • Exposure switch.
  • mAs and kVp meters.
72
Q

Extending Tube Life

  • X-ray tube life may be extended by using ————– appropriate for each examination.
  • Use of ———
  • ——— results in reduced x-ray tube life.
A
  • minimum radiographic factors of ma, kVp, and exposure time
  • faster image receptors.
  • Excessive heat
73
Q

Extending Tube Life

  • X-ray tube life may be extended by using ————– appropriate for each examination.
  • Use of ———
  • ——— results in reduced x-ray tube life.
A
  • minimum radiographic factors of ma, kVp, and exposure time
  • faster image receptors.
  • Excessive heat
74
Q

Prepares the x-ray tube to receive high heat load.

A

Warm up Procedures

75
Q

An example of a warm-up technique
an initial exposure of ——————
followed by a second exposure in which the mA is raised to —

A
  • 50 kVp, 100 mA, at 1/30 second
  • 200
76
Q

Other Ways of Extending Tube Life

  • Minimize ——- (preparation) time.
  • Limit ——– operations.
  • Use ———— (mA).
  • Do not make a ——- on a cold tube.
  • Adhere to ————–
  • Limit operations to —- of maximum single exposure ratings.
  • Do not exceed the ————– or dissipation rate of the target.
  • Do not ———- rapidly from one position to another.
  • Avoid —— between spot-films
A
  • filament boost
  • rotor/start/stop
  • lower tube current
  • high mA exposure
  • rating charts and anode heating and cooling curves
  • 80%
  • anode thermal capacity
  • rotate the tube housing
  • long intervals
77
Q

X-ray Tube Aging

  • ———- to the internal surface of the glass envelope will cause some electrons strike the glass envelope
A

Deposition of Filament Tungsten

78
Q

X-ray Tube Aging

———– at tube window will add ———–,
will harden the beam (less useful x-ray will emit from tube window).

A
  • Tungesten layer deposited
  • extra filtration
79
Q

X-ray Tube Aging

By the time, glass envelope that struck by electrons ————-, which cause tube failure due to x-ray tube is not vacuum anymore.

A

produces gas (gassy tube)

80
Q

X-ray Tube Aging

can be diagnosed, as oil sucked into the tube insert, when the tube is turned, can easily be heard.

A

Punctured Tube

81
Q

X-ray Tube Aging

Careless handling might break the glass envelope, stress fracture may occur (affect vacuum condition).

A

Carelessness

82
Q

X-ray Tube Aging

  1. Damages to Anode
    * ———— - cause to different expansion and reduce the radiation output.
    * ———— - sudden injection of great heat. (not apply warm up)

Damages to Anode

A
  • Surface crazing (rough)
  • Anode disc may crack
83
Q

X-ray Tube Aging

cause to slow rotation / not rotate. Due to surface melting, it will release gas (gassy
tube) because the heat applied to small area.

A

Bearing Damage

Damages to Rotor and Bearings

83
Q

X-ray Tube Aging

Recommendations
* —— (as necessary only)
* provide —— to reduce speed after exposure (special unit)
* ———– prevent or terminate exposures if anode is not rotating

Damages to Rotor and Bearings

A
  • minimize time
  • braking
  • interlock circuit
84
Q

X-ray Tube Aging

Filament thin with age or time through evaporization or mechanical damage.

A

Damages to Filament

85
Q

X-ray Tube Aging

1) As filament becomes thinner (evaporization), its ——– decreases - reducing mA.
2) ——— (on and off) fault — problem on filament circuit

A
  • resistance
  • Intermittent
86
Q

X-ray Tube Aging

Reccomendations:
1. boosting the filament the ——– as possible
2. avoid the use of —— unnecessarily

Damages to Filament

A
  • shortest time as possible
  • high mA
87
Q

X-ray Tube Aging

Oil escape from tube will cause a reduction of insulation level and it is harmful to operator.

A

Damages to Tube Housing

88
Q

X-ray Tube Aging

Evidences of leakage:
* —- outside the housing
* a ——- on the floor under the tube

A
  • oil
  • a spot of oil
89
Q

X-ray Tube Aging

Broken in stator windings (which provide electromagnetic field) will cause no or intermittent rotation.

As a result, it will harm to the —–.

A
  • Damages to Stator
  • anode target
90
Q

Recommendation
* Provide safety circuit to ——

Damages to Stator

A

terminate exposure

91
Q

single phase power rating

A

V = (0.7) kV x mA/1000

RT 209 (4 decks)

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