Brainscape's Knowledge GenomeTM

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


See full index

Board Review Final sets a > Mixed Review Deck 4 > Flashcards

Mixed Review Deck 4 Flashcards

1
Q

The annual occupational dose limit is valid for what radiations?

A

Beta, x and gamma

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

Why are alpha particles practically harmless as an external source of radiation?

A

They can only travel a few centimeters in air

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

Who can determine if a patient needs oxygen?

A

Only a physician bc it is considered a drug.

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

What is the unit for spatial frequency?

A

Lp/mm

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

When determining lp/mm with a given pixel size, how wide is the smallest line on the image? How many pixels make a line pair?

A

Line is 1 pixel wide
2 pixels make a line pair

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

Device that monitors the luminance response and uniformity of monitors used in digital imaging?

A

Photometer. There are 2 types, near-range and telescopic.

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

In amorphous selenium FPDs, the term amorphous means…

A

A crystalline material lacking its typical crystalline structure

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

A capacitor discharge mobile unit is a/k/a…

A

A condenser discharge unit

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

What is the major advantage and the major disadvantage of a capacitor discharge mobile unit?

A

Advantage is its light weight due to carrying no batteries so it needs no motor to drive or brake.

Disadvantage is as capacitor discharges its charge, kV decreases throughout exposure, so it must be charged between exposures.

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

Capacitor discharge units use capacitors to power the…

A

Xray tube only (no motor needed to drive it)

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

To compensate for variations in gain across a digital receptor, what maintenance steps should be taken?

A

Conduct a calibration correction for image nonuniformity.

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

A test pattern, such as the TG 18-CT test pattern, is used to qualitatively evaluate

A

The luminance response of a digital display monitor

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

A spinning top test should show ___ dots for every _____ in the generator’s waveform.

A

1 dot per pulse. So if the generator should be producing a waveform with 60 pulses per second, in 1 second the test should show 60 dots.

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

Give the number of pulses pet second produced by a ..

Single phase generator, half wave rectified
Single phase, full wave rectified
3 phase, half wave rectified
3 phase, full wave rectified

A

Single phase, half wave rectified: 60 pps
Single phase, full wave rectified, 120 pps

3 phase, half wave rectified: 180 pps
3 phase, full wave rectified: 360 pps

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

Which projection should be performed and evaluated before performing a Settegast projection for trauma?

A

Lateral patella to rule out a transverse fracture

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

The xray unit of exposure defines…

A

Air kerma

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

SI unit describing dose to biologic material

A

Sv

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

A fractional focus tube will have a focal spot size of ___ or smaller and is used in ______ radiography to maintain ______.

A

0.3 mm, magnification, image sharpness

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

What is the effect of a deeper focusing cup on actual focal spot size?

A

Keep electron cloud confined more effectively (smaller actual focal spot)

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

Dysplasia refers to

A

Abnormal development of tissue

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

Roadmapping in fluoro …

  1. Keeps most recent fluoroscopic imsge on screen
  2. Aids in placement of guidewires and catheters
  3. Reduces need for continuous xray exposure to the patient
A

All 3

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

A 4 diode rectifier in diamond shape produces _____ rectification.

A

Full wave

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

An inverter is part of what type of xray generator?

A

High frequency

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

Define a sentinel event

A

A fluoroscopic skin dose of greater than 15 Gy. This must be reported to the Center for Devices and Radiological Health (CDRH)

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

Leakage radiation (per NCRP 102) must not exceed…

A

1 mGy(air) per hour at 1 m from the tube

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

As the anode target angle increases…
Effective focal spot size _____
Spatial resolution ____
Anode heat capacity _____

A

Effective FSS increases
Spatial resolution decreases
Anode heat capacity is unchanged bc actual FSS is unchanged

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

For a scapula y lateral shoulder, the humeral head should sit…

A

Superimposed over the y junction formed by the acromion and coracoid process

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

3 essential criteria for xray production

A

Source of electrons
Means to accelerate electrons
Target material capable of causing the electrons to decelerate

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

A tube placed into a cavity to introduce or withdraw material

A

Cannula

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

Adult orthoentgenography is radiographic measurement of…
And requires how many exposures?

A

Measurement of long bones of lower extremity
3 exposures: hip, knee and ankle

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

In the CR reader, some of the laser light is redirected to a reference detector by way of…
In order to…

A

A beam splitter
To monitor laser beam intensity to adjust for any fluctuations

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

Define each, and which are most and least radiosensitive?

Myelocyte
Myocyte
Erythroblast
Megakaryocyte

A

Myelocyte is a wbc precursor
Myocyte is a mature muscle cell
Erythroblast is a rbc precursor
Megakaryocyte is a platelet precursor

Least radiosensitive: myocyte
Most radiosensitive: erythroblast

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

How long is each portion of the small intestine?

A

Ileum, 6 to 12 feet
Jejunum, 3 to 6 ft
Duodenum, about 10 inches

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

Acute abdomen series includes

A

AP erect (or L lateral decubitus)
AP recumbent
PA chest (erect)

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

What’s in a 3 way abdomen study

A

AP recumbent
AP erect
L lateral decubitus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Best position to see anterior and posterior aspects of stomach and retrogastric space?

A

Lateral recumbent (usually R lateral)

37
Q

Peristaltic activity is greatest in this position, so it’s best to demonstrate the stomach’s emptying mechanism.

A

RAO (prone)

38
Q

Best position/projection of sigmoid colon

A

PA axial; prone; CR 35 degrees caudal to midline at ASIS level

39
Q

Best position for opening the ascending colon and hepatic flexure

A

RAO (or LPO)

40
Q

Kidneys lie at what vertebral levels

A

T 12 to L3

41
Q

Ureteral filling of contrast is best viewed in what position and projection?

A

PA/prone

42
Q

Define free radical

A

Atom with unpaired electrons, short lived but highly reactive, can travel from its source and break chemical bonds in order to pair with another electron

43
Q

Dynamic range

A

Range of exposures that can be captured by a detector

44
Q

Current flowing thru a coil of wire?
What’s it called if you add a ferromagnetic core?

A

Solenoid
Electromagnet

45
Q

Voltage ripple associated with a 3 phase 12 pulse rectified generator in pulses per half cycle

A

3 pulses per half cycle

46
Q

If 1 rectifier were malfunctioning, the resulting mAs would be…

A

Half that expected

47
Q

Switching from single phase to 3 phase equipment, how to adjust kVp?

A

Reduce by 12%

48
Q

Radiologic imaging uses ___ ___ computer processing

A

Real time

49
Q

Principle reason for image integration in digital fluoroscopy

A

Improves contrast resolution

50
Q

Most common cause of x-ray tube failure

A

Vaporized tungsten on glass envelope

51
Q

Minimum acceptable TV SNR in digital fluoroscopy

A

1000:1

52
Q

The mask image in subtraction imaging is usually the…

A

Image just preceding contrast injection

53
Q

Interrogation time

A

In digital imaging, time it takes to switch on the xray tube

54
Q

If an xray produced using AEC is overexposed bc required exposure is shorter than the minimum response time you should…

A

Decrease mA

55
Q

Flux gain measures increase in ___ due to conversion efficiency of the ____

A

Light photons
Output screen/phosphor (due to increased kinetic energy of the electrons)

56
Q

Define minification gain and it’s formula

A

Increase in brightness or intensity due to number of electrons at the input screen being compressed to a small output screen

INPUT DIAMETER^2 / OUTPUT DIAMETER ^ 2

57
Q

Part of II tube responsible for the liberation of electrons which are then accelerated toward the anode disc

A

Photocathode

58
Q

Name for the process of converting xray and light energies into electrons from a photocathode surface

A

Photoemission

59
Q

What’s the voltage difference (potential difference) between the photocathode and anode in most image intensifiers?

A

25,000 to 30,000 V

60
Q

The input phosphor is composed of

A

Cesium iodide

61
Q

The photocathode is made of

A

A cesium antimony compound

62
Q

The output phosphor is made of

A

Zinc cadmium sulfide

63
Q

Formula for total brightness gain

A

Flux gain X minification gain

64
Q

Formula for Flux gain

A

of light photons at output / # of xrays at input

65
Q

The photocathode converts..

A

Visible light to electrons

66
Q

To maintain brightness gain, a decrease in Flux gain would require…

A

An increase in minification gain

67
Q

Why are the II input phosphor and the photocathode both concave in shape?

A

Reduce distortion (travel distance between photocathode and output phosphor is exactly equal for electrons)

68
Q

The photocathode and input phosphor are ___ in shape

A

Concave

69
Q

Continuous fluoro exposes at a rate of ___ frames per second

A

30

70
Q

In mag mode…
A. Why is minification gain decreased?
2. What compensates for the loss in brightness gain?

A

A. Less photoemission from the photocathode due to less input diameter
B. Increase Flux gain by increasing kV or mA

71
Q

Magnification with multifield image intensification is accomplished by shifting the electron stream focal point forward… how?

A

Place a stronger negative charge on the electrostatic focusing lenses

72
Q

Annual effective dose per person FROM NATURAL BACKGROUND radiation is approx…

A

3.0 mSv

73
Q

An acute dose of ____ is required to produce cataracts

(Or an occupational/fractionated dose of ___ Gy)

A

2 Gy acute
10 Gy fractionated

74
Q

Threshold dose for lymphocyte depletion

A

0.25 Gy

75
Q

Positive beam limitation must be accurate within ___ % of SID for a single side and within ____ % of SID for all sides

A

3% and 4%

76
Q

Threshold doses for each of the 3 forms of ARS

A

Hematopoietic: .7 to 10 Gy
GI: 10 to 100 Gy
CV or CNS 50 Gy

77
Q

What is SED(50) for humans

A

*dose required to produce erythema in 50% of population

Humans: 5 Gy

78
Q

How is oxygen enhancement ratio of cells or tissue determined

A

Dose required to cause effect without oxygen / dose required to cause that effect with oxygen

79
Q

When during the cell cycle are cells most radiosensitive?

A

Gap 2 of interphase and mitosis (M)

80
Q

Divisions of interphase and when are cells least radiosensitive?

A

Gap 1, S (synthesis) and Gap 2

Synthesis (DNA replication), least radiosensitive

81
Q

Give radiation weighting factors for…

X and gamma rays
Protons
Slow neutrons
Fast neutrons
Alpha particles

A

X/gamma rays 1
Protons 2
Slow neutrons 10
Fast neutrons 20
Alpha 20

82
Q

1 angstrom is

A

10 ^ -10 m

83
Q

Wavelength of diagnostic xrays

A

10^-8 to 10^-12 m

84
Q

All electromagnetic radiations travel at what speed

A

Speed of light, 3 x 10^8 meters/sec

Or 186,000 miles/s

85
Q

Length of latent period of ARS is inversely related to …

A

Amount of exposure received

86
Q

Annual US background radiation exposure
1 CXR dose
Whole body CT dose

A

6 mSv
0.10 mSv
10 mSv

87
Q

Dose response curve that predicts deterministic effects

A

Nonlinear threshold

88
Q

Effects whose probability but not severity is dose dependent

A

Stochastic

Board Review Final sets a (12 decks)

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