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physics > chapter 6 (The x ray imaging system ) > Flashcards

chapter 6 (The x ray imaging system ) Flashcards

1
Q

A falling load generator allow for a _________ exposure when compared to a fixed mA.

A

Shorter

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2
Q

A________ transformer is used to increase filament current.

A

Step- down

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3
Q

The unrectified voltage waveform _________before the x ray tube.

A

has both a positive and negative component.

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4
Q

which of the following is a disadvantage of a three phase power compared to a single phase?

A

Higher costs

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5
Q

what material are most patient tables made of ?

A

Carbon fiber

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6
Q

Assuming the same maximum kvp and mAs, the power rating of a single phase system is ______ a three phase system.

A

less than

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7
Q

_________ is a voltage waveform that results in thousands of pulses per second after rectification.

A

High frequency

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8
Q

A three phase waveform has _______ ripple.

A

13%

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9
Q

The x-ray tube current is monitored on the __________.

A

secondary side of the high voltage transformer.

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10
Q

with half wave rectification current flows through the x ray tube during the ________part of the cycle.

A

positive

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11
Q

The difference in waveform between primary and secondary sides of the high voltage transformer is _______

A

Amplitude

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12
Q

Full wave rectifiers use both the positive and negative parts of a wave, which __________.

A

cuts the exposure time in half

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13
Q

The_____ timer operates based on a wound spring.

A

mechanical

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14
Q

The autotransformer has_____ coil(s).

A

one

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15
Q

The most accurate type of timer is the ________ timer.

A

Electronic

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16
Q

which statement is true about machines using a half-wave rectified voltage waveform?

A

All of the above.
- they require twice the exposure time of full- wave rectified circuits.
- Electrons are accelerated from the cathode to anode of the x ray tube in the positive voltage cycle.
- they do not operate in the negative portion of the waveform
- they have a 100% ripple.

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17
Q

________ require a back up timer.

A

AEC timers.

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18
Q

Variations in power distribution to the x ray machine are corrected by the _________.

A

line voltage compensator.

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19
Q

The three main parts of the x ray imaging system are the ________, ________ and ________.

A
  • X- ray tube
  • operating console
  • high voltage generator.
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20
Q

As the number of pulses increase over a fixed time, the ripple______.

A

decreases.

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21
Q

When high voltage is on the cathode side of a vacuum tube rectifier, _______.

A

there is NO current flow

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22
Q

The automatic exposure control (AEC) terminates the exposure when ________.

A

sufficient radiation reaches the image receptor.

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23
Q

The generator that produces the least penetrating x rays and results in a highest radiation dose to the patient for the same kvp is the _______.

A

single phase half wave rectified.

24
Q

The voltage waveform supplied to the primary side of the high voltage transformer is________.

A

unrectified

25
Q

The first component to receive power in the x ray circuit is the ________.

A

autotransformer.

26
Q

The rectification process converts ________.

A

AC to DC

27
Q

A high frequency waveform has _____ ripple.

A

1%

28
Q

What is the industry standard formula for calculating high voltage generator power rating?

A

Power= f x max mA (@100kvp and 100 ms) x 100 kvp.

29
Q

An autotransformer has a primary current of 800 mA. If there are 350 turns on the primary side and 460 turns on the secondary side, what is true about the transformer?

A

The turns ratio is greater than 1.

30
Q

In modern imaging systems, the components for rectification are_______.

A

solid state semiconductors.

31
Q

Low voltage ripple results in ________ radiation quantity and quality.

A

increased.

32
Q

The x ray machine console allows you to control _____,_______ and _____.

A
  • kV
  • mAs
  • focal spot size
33
Q

The high voltage generator contains the _______ the ______ and the _______.

A
  • high voltage transformer
  • filament transformer
  • rectifiers
34
Q

_______ is a voltage waveform that results in 360 pulses per second after rectification.

A

Three phase.

35
Q

What is the main goal for a mAs timer?

A

minimize the effects of patient motion.

36
Q

What type of time can be used for rapid serial exposure and is very reproducible?

A

Electronic timer.

37
Q

Voltage across the x ray tube is most constant with ______

A

High frequency generators.

38
Q

_____ is measured by mA and _____is measured by mAs.

A

Current , charge.

39
Q

the x ray generator with the lowest power rating is the _________imaging system.

A

single-phase.

40
Q

The high voltage transformer has____

A

a turns ratio greater than one.

41
Q

which of the following results in best utilization of the voltage waveform?

A

full wave rectified.

42
Q

A step - down transformer is located in the _____ circuit.

A

filament

43
Q

semiconductor reciters have two material types a p- type material with excess _____ and an n- type material with excess______.

A

holes, electrons.

44
Q

The filament transformer ______.

A

increases the current.

45
Q

The timer that operates based on a shaft rotating at a set speed is the _______ timer.

A

synchronous.

46
Q

Voltage is______ related to the turns ratio.

A

directly

47
Q

In full wave rectification, the wave applied across the x ray tube is always_______.

A

positive.

48
Q

All the console controls are on the ______ side of the high voltage transformer and the ______side of the filament transformer

A

primary, primary

49
Q

A single phase waveform has ____ripple.

A

100%

50
Q

Ionization chambers are ________in AEC systems.

A

between the patient and the image receptor.

51
Q

the kvp meter is located ________.

A

on the primary side of the high voltage transformer.

52
Q

The _____ circuit provides electrons for the x ray tube current

A

filament.

53
Q

In a semiconductor rectifier, when higher potential is placed on the P -side______.

A

there is Current flow through the diode.

54
Q

Power to the primary side of the high voltage transformer comes from the _____.

A

secondary side of the autotransformer.

55
Q

The inverter is the device that “chops” the waves into smaller shorter waves in a _______.

A

high frequency generator.

56
Q

Current is _____ related to the turns ratio.

A

inversely

physics (4 decks)

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