FluoroPrep Flashcards

1
Q

What does automatic brightness control do?

A

ABC keeps the light output of the image intensifier constant over variations of patient attenuation (different tissue density and thickness)

Syllabus Page 23

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2
Q

Which body area has the largest distribution of fluoroscopic examinations?

A
GI tract
(The gastrointestinal tract has the largest distribution of fluoroscopic examinations, including the barium enema, upper GI series, and KUB. Syllabus pg 1.)
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3
Q

This occurs when an incident x-ray photon is annihilated near the nucleus of an absorbing atom with the subsequent production of an electron and a positron.

A

pair production

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4
Q

What are the three ways in which energy is lost during x-radiation?

A
  1. photoelectric effect
  2. Compton scattering
  3. pair production
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5
Q

This occurs when a collision occurs between an x-ray photon and an INNER orbital electron.

A

photoelectric effect

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6
Q

This occurs when an interaction occurs between an x-ray photon and an outer orbital electron

A

Compton scattering

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7
Q

Digital fluoroscopy systems are commonly used to record images of:

A

vessels

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8
Q

How do you get a reading from a pocket ionization chamber?

A

They are either self-reading OR can be read by a special device.
Pocket ionization chambers discharge a capacitor by ionization of air within a chamber when in the presence of ionizing radiation. The rate of discharge depends on the intensity of the radiation.

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9
Q

This component changes the magnification mode by changing the field of view (FOV).

A

electrostatic lens

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10
Q

Magnification mode increases resolution from about:

A

4lp/mm to 6lp/mm

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11
Q

What is the maximum exposure rate allowed for fluoroscopic equipment manufactured after August 1, 1974, without automatic exposure controls (AEC)?

A

The allowable exposure rate in equipment WITHOUT automatic exposure control is 5 rads/minute.
Syllabus pg 41.

(WITH AEC, the max exposure rate is 10 rads/min)

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12
Q

What is the typical setting (in mA) during spot filming?

A

150 mA

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13
Q

How long does it take for a fluoroscopy table to move from the horizontal to vertical position?

A

20 to 30 seconds

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14
Q

The acceleration of the electron stream inside the image intensifier requires a potential difference (voltage) of?

A

25 kV

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15
Q

The output phosphor of an image intensifier converts ____ to ____?

A

electrons to light

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16
Q

The point in the image intensifier tube where the electrons crossover is called what?

A

The electronic focal point or spot

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17
Q

In order to prevent light from scattering back to the photocathode layer of the image intensifier, a thin sheet of aluminum is placed onto the ?

A

output phosphor

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18
Q

The input phosphor of most modern image intensifiers is made of?

A

cesium iodide

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19
Q

The output phospor of most modern image intensifiers is made of?

A

zinc cadmium sulfide

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20
Q

The electronic signal which carries the information from the television camera to the monitor is termed the?

A

video signal

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21
Q

In order to prevent the flicker effect during viewing of the television image, a technique called __ is used.

A

interlaced horizontal scanning is used.

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22
Q

The electron beam in the television camera tube is produced by?

A

thermionic emission

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23
Q

The target assembly of a television camera tube consists of?

A

target, signal plate, window

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24
Q

In the optical coupling arrangement, which is nearest the television camera tube?

A

camera lens

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25
Q

One television frame rate is equal to?

A

2 television fields

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26
Q

Horizontal television resolution is limited principally by what?

A

bandpass (bandwidth)

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27
Q

The maximum operating potential of most modern fluoroscopic x-ray tubes is approximately?

A

150 kVP

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28
Q

The target or photo-conductive layer of the vidicon tube in the television camera, which serves like tiny capcitorrs, is most often composed of?

A

antimony trisulfide

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29
Q

In the optical coupling arrangement, which is nearest the image intensifier?

A

objective lens

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30
Q

The central portion of the image intensifier tube possess the greatest?

A

resolution

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31
Q

The function of an ABC mechanism of the image intensified fluoroscopic system is to?

A

maintain a fixed dose rate to the image intensifier

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32
Q

In order to create an appearance of motion without flicker, a frame must be complete every?

A

1/30 sec

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33
Q

X-ray tube housing must be so constructed that the leakage radiation at a distance of 1m from the target cannot exceed ?

A

100 mR/hr

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34
Q

A “radiation area” is any area accessible to personnel , in which there exists radiation at such levels that a major portion of the body could receive in any one hour a dose in excess of?

A

5 millirems in any one hour (0.05 mSv)

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35
Q

The output intensity of a fluoroscopy tube is measured iin?

A

milliroentgens (mR)

36
Q

A “HIGH radiation area” is any area accessible to personnel , in which there exists radiation at such levels that a major portion of the body could receive in any one hour a dose in excess of?

A

100 mrem (1.0 mSv) in any one hour

37
Q

A film badge report expressed an individual’s radiation dose equivalent in?

A

Rem

((Roentgen Equivalent Man) - Known as the biological dose. This is used to measure the dose equivalent.

38
Q

When the televised intensified image is viewed on a TV monitor, it will possess ______ than the image on a mirror optic viewing system.

A

higher contrast, and lower patient dose

39
Q

When TV viewing of the image and cine spot films are necessary, a/an ____ is used for image coupling.

A

A tandem mirror device (beam splitter)

40
Q

The most common way of characterizing the quality of an x-ray beam.

A

HVL

41
Q

How many HVLs are in one TVL?

A

3.3

42
Q

The ratio of the luminance in candelas of the output phosphor to the input phosphor exposure rate in milliroentgens/sec. defines?

A

conversion factor

43
Q

The time it takes for the human eye to adjust to low light levels of conventional fluoroscopy is called?

A

dark adaptation time

44
Q

The television camera tube converts the light image from the image intensifier into a/an?

A

electronic image

45
Q

When the video signal is modulated, that means its ____ is changing in a controlled fashion?

A

frequency

46
Q

The point in the imaging chain where the fewest number of x-ray or light photons are used to convey the signal is referred to as:

A

quantum sink

47
Q

The brightness of an image intensified-fluoroscopic image is about ____ greater than a conventional fluoroscopic image.

A

5,000 to 20,000 times

48
Q

How thick do primary barriers need to be?

A

1.5mm of aluminum OR (1/16 of inch lead)

49
Q

In a fixed R/F room, the minimum height of a primary barrier is?

A

6.8 feet (80 inches)

~7 ft

50
Q

NCRP states that the risk to the embryo/fetus is considered to be negligible at 5 rads or less when compared to other risks of pregnancy. The risk of malformations is significantly increased above control levels at doses above ?

A

15 rads

51
Q

Tabletop equivalent thickness must not exceed

A

1mm Aluminum

52
Q

In cinefluorography, the maximum magnification is achieved with

A

total overframing

53
Q

What serves as the primary protective barrier for a dedicated C-arm fluoroscopic unit?

A

input phosphor of the image intensifier

54
Q

An area controlled by state regulation and in which radiation safety rules are enforced and occupational exposure of personnel is under the supervision of the radiation safety officer is called?

A

controlled area

55
Q

Fluoroscopic systems operating with a grid in place will have exposure rates

A

1.5 to 2x higher

56
Q

During cinefluorography, the patient dose is directly proportional to the :

A

size of the frame
time of exposure
frames per second

57
Q

According to the California Radiation Control Regulations the target-to-tabletop distance for fluoroscopic x-ray equipment SHOULD NOT be less than __ inches and SHALL NOT be less than __ inches.

A

18; 12 inches

58
Q
Which of the following does not affect the amount of scattered radiation produced?
A. body thickness
B. collimation
C. focal spot size
D. kVP
A

focal spot size

59
Q

What is the formula for calculating the maximum permissible lifetime dose for a technologist?

A

Age x 1 REM (OR age x 10mSv)

60
Q

A high radiation area is defined as an area in which an individual could receive ?

A

100 millirems in any one hour.

61
Q

Which of the following will decrease patient exposure without decreasing the brightness?
A. increasing field size (collimation)
B. increasing kVP
C. increasing the distance of patient to image intensifier
D. increasing TPD

A

increasing TPD (target-to-panel distance)

62
Q

The component in the image intensifier that changes the field of view from the standard to magnification mode is the?

A

electrostatic lenses

63
Q

The California Radiation Control Regulations require that individual radiation monitoring records be preserved by the employer after termination of employment for how long?

A

indefinitely

64
Q

The maximum exposure level while using the boost position is ?

A

20R/min

65
Q

During a CINE exam in which 35 mm film and frame rate of 30 frames/second are utilized, the approximately exposure to the skin for one minute of CINE is

A

1000-5000 mR/min

66
Q

Any fluoroscopic unit with AEC or cine camera must be calibrated by a physicist at least

A

every year

67
Q

When positive contrast media are used, the primary x-ray interaction taking place within the contrast media is

A

the photoelectric effect

68
Q

The output intensity of a fluoroscopic tube is measured in?

A

mR

69
Q
Exposure rate is least effected by which of the following?
A. film recording device
B. kVP
C. mA
D. filtration
A

film recording device

70
Q

The central portion of the image intensifier tube possesses the greatest

A

detail

71
Q

Image quality utilizing an image intensifier is improved as the size of the xray beam is tightly collimated because:

A

less scattered radiation reaches the input phosphor

72
Q
When the xray source is below the patient, the majority of scatter radiation is directed towards the: 
A. floor
B. ceiling
C. image receptor
D. upper body of medical worker
A

floor

73
Q

The acute form of radiation dermatitis results from an exposure of __ Gy.

A

2-8 Gy

74
Q

Grid removal may reduce patient dose by a factor of __ or more.

A

2 or more

75
Q

Which organization ensures uniform reporting of data and information on radiation risks and protection?

A

ICRU (International Commission on Radiation Units and Measurements)

76
Q

Public Law 90-602 is related to what?

A

the creation of the CDRH (Center for Devices of Radiological Health)

77
Q

What is the focus of the BEIR Report?

A

comprehensive risk estimate for cancers and other health effects from low levels of ionizing radiation exposure

78
Q

The Consumer-Patient Radiation Health and Safety Act of 1981 mandates the federal government to set minimum standards for:

A

the accreditation of education programs for people who administer radiologic procedures and the certification of those practitioners

79
Q

The average horizontal travel distance of the telescoping C-arm is __ cm.

A

20 cm

80
Q

The average C-arm height manipulation range is __cm.

A

46 cm

81
Q

The audible 5-minute fluoroscopy timer may be reset after __ seconds.

A

2 sec

82
Q

Advantages of fixed fluoroscopy systems over mobile fluoroscopy systems include:

A

better image quality

reduced radiaiton exposure

83
Q
The process of "leveling and windowing" of digital images determines the image \_\_\_\_?
A. spatial resolution
B. contrast
C. pixel size
D. matrix size
A

contrast

84
Q

What does window WIDTH control in radiography?

A

contrast
Increasing width will reduce display contrast , whereas decreasing the width increases the brightness interval between two consecutive pixel values.

85
Q

What does window LEVEL control in radiography?

A

brightness

86
Q

What is “windowing”?

A

also known as grey-level mapping, contrast stretching, histogram modification or contrast enhancement is the process in which the CT image greyscale component of an image is manipulated via the CT numbers; doing this will change the appearance of the picture to highlight particular structures.