Brainscape's Knowledge GenomeTM

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


See full index

Physics II Exam 1 > Chapter Six > Flashcards

Chapter Six Flashcards

You may prefer our related Brainscape-certified flashcards:
Physics 101 flashcards AP® Physics flashcards
1
Q

list the external components of the x ray tube

A
  1. support system (i.e.. floor to ceiling, ceiling, C-arm)
  2. protective housing
  3. enclosure (glass or metal)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

name the internal components of the x ray tube

A
  1. cathode (filament and focusing cup)

2. anode (rotating, stationary)

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

describe the protective housing for the x ray tube

A

lead-lined (made of metal) w/ two electrical wires that attach to the tube through a high voltage connector

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

what are the roles of the protective housing

A

provides mechanical support for the time
electrical insulator
heat dissipater

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

what is leakage radiation

A

anything that exits outside of the window (light field)

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

true or false; there is never leakage radiation

A

False…there is ALWAYS leakage radiation

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

were older or newer tube enclosures made of glass

A

older

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

what material are newer tube enclosures made of

A

metal

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

why was there a switch to metal enclosures from glass

A

the glass allowed gases to form and diminished the tube life due to arcing

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

what is the advantage to a metal enclosure

A

maintains consistency and made for a longer tube life

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

the ______ is the positive side and the _______ is the negative side

A

anode

cathode

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

true or false; the cathode and the anode from a diode

A

true, they are both electrodes and together they form a diode

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

what are the two primary parts the cathode

A

filament

focusing cup

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

what is the filament made of

A

thorium

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

why is thorium a material of choice

A

aides in thermionic emission and makes it more efficient

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

what is the purpose of the focusing cup

A

makes electrons travel in a specific direction

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

true or false; the focusing cup has a charge, if so what is the charge

A

true, negative charge

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

what are the four things that make the focusing cup effective

A

size
shape
location
charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

true or false; the beam is confined when using a focusing cup and decreases the consistency
explain

A

False: while the beam is confined when using a focusing cup it INCREASES the consistency

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

true or false; filament current affects tube current

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

low filament current = _____ tube current

A

no

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

a _____ increase in filament current = a large increase in tube current

A

small

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

what is the range for a low kVp

A

0-50

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

in what unit is:
tube current
filament current measured in

A

tube: miliamperes (mA)
filament: amperes (A)

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

true or false; there is no charge created in thermionic emission

A

false! thermionic emission creates a space charge

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

list the steps of the space charge

A

electrons leave filament
electron cloud surrounds filament
cloud repels new electrons from filament

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

describe the space charge effect

A

makes it harder to boil off new e- b/c there is no where for them to go

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

what is a saturation current

A

at a given filament current a point reaches a maximum level at which all of the e- have been used

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

at what point is something space charge limited

A

thermionic emission at low kVp and high mA

30
Q

how many focal spots do most diagnostic x ray tubes have

A

two
one large
one small

31
Q

describe the types of focal spots

A

small: better spatial resolution
large: large body parts; high heat

32
Q

what are the functions of the anode

A

conducts electricity
contains the target
radiates heat (heat dissipator)

33
Q

how many types of anodes are there and name them

A

two; stationary and rotating

34
Q

list the materials that can be used in the anode

A

tungsten, copper, molybdenum, graphite

35
Q

in what kind of case is a stationary anode used in

A

dental

36
Q

what is the advantage of a rotating anode

A

higher heat tolerance

37
Q

what can be adde to tungsten to make it more durable and strong

A

rhenium

38
Q

where is copper used in the anode and why

A

it is used in the shaft and it conducts electricity

39
Q

what is the purpose of rotating the anode

A

so that heat diets just hit one place

40
Q

what is the RPM range for the anode

A

3,400-10,000 RPM

41
Q

what is the target

A

the area struck by the e- from the cathode

42
Q

why is tungsten a good material to be used in the anode

A

high atomic #
thermal conductivity
high melting point

43
Q

what materials is the inner portion of the anode made of

A

graphite and molybdenum

44
Q

describe the stator

A

electromagnets arranged to allow for electromagnetic induction and rotation

45
Q

the rotor is made of ____ and _____

A

copper and soft iron

46
Q

true or false; the rotor is outside of the glass envelope while the stator is on the inside of the glass

A

false; the STATOR is outside of the glass envelope while the ROTOR is on the inside of the glass

47
Q

how does the stator work

A

it energizes winding creating a magnetic field and inducting rotation

48
Q

what is the effective focal spot

A

the portion that the patient views

49
Q

the target can also be called ______

A

focal spot

50
Q

describe the line focus principle (LFP)

A

an angle is created on the anode to allow for detail and heat capacity

51
Q

in regard to the LFP what is done with the focal spots

A

the effective focal spot is made smaller than the actual focal spot

52
Q

what is the common anode angle

A

5-20 degrees

53
Q

true or false; the effective focal spot is controlled by the actual focal spot

A

true

54
Q

the _____ the effective focal spot the smaller the coverage area

A

smaller

55
Q

small angle _____ effective focal spot

A

small

56
Q

true or false; the intensity of the beam is altered due to the LFP

A

True

57
Q

the anode heel effect is a consequence of what

A

LFP

58
Q

describe the anode heel effect

A

x ray intensity is greater on the cathode side of the tube

59
Q

the smaller the anode angle the _____ the heel effect

A

greater

60
Q

what is off-focus radiation

A

rebounding e- causing x rays to be produced outside the focal spot

61
Q

off-focus radiation is also called what

A

extra focal radiation

62
Q

what does extra focal radiation do to image contrast

A

reduces it

63
Q

what is the most common cause of tube failure

A

excessive heat especially by using maximum techniques

64
Q

what are the three ways to dissipate heat in the x-ray tube

A

radiation
conduction
convection

65
Q

what is conduction

A

transfer of heat through touch; one area of material to another

66
Q

describe convection

A

liquids or gases; in the tube: oil bath that it is submerged in

67
Q

infra red is associated with what kind of heat dissipation

A

radiation

68
Q

what is the most frequent cause of abrupt tube failure

A

electron arcing from the filament to the enclosure b/c of vaporized tungsten

69
Q

name the three types of rating charts

A

radiographic rating chart
anode cooling chart
housing cooling chart

70
Q

what is the heat unit (HU) conversion for a single phase

A

HU= (kVp)(mA)(s) = 0.7J

71
Q

what is the heat unit (HU) conversion for a three phase

A

HU = 1.4 (kVp)(mA)(s) = 1J

Physics II Exam 1 (1 decks)

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