RT2 Flashcards
1
Q
1 . Low voltage X-ray tubes are generally fitted with windows made of:
a. plastic
b. beryllium
c. glass
d. lead
A
b. beryllium
2
Q
- A monochromatic X-ray beam is:
a. a narrow beam used to produce high-contrast
radiographs
b. also referred to as a heterogeneous X-ray beam
c. a beam containing only characteristic X-radiation
d. a beam consisting of a single wavelength
A
d. a beam consisting of a single wavelength
3
Q
- The general method of producing X-rays involves the sudden deceleration of high velocity electrons in a solid body called a:
a. focus cup
b. filament
c. target
d. cathode
A
c. target
4
Q
- If it were necessary to radiograph a 18 cm (7 in.) thick steel product, which of the following gamma ray sources would most likely be used?
a. Co-60
b. Tm-170
c. lr-192
d. Cs-137
A
a. Co-60
5
Q
- A Co-60 gamma ray source has an approximate practical thickness limit of:
a. 63 mm (2.5 in.) of steel or its equivalent
b. 102 mm ( 4 in.) of steel or its equivalent
c. 23 cm (9 in.) of steel or its equivalent
d. 28 cm (11 in.) of steel or its equivalent
A
c. 23 cm (9 in.) of steel or its equivalent
6
Q
- The absorption of gamma rays from a given source when passing through matter depends on the:
a. atomic number, density, and thickness of the
matter
b. Young’s modulus value of the matter
c. Poisson’s ratio value ofthe matter
d. specific activity value of the source
A
a. atomic number, density, and thickness of the
matter
7
Q
- The fact that gases, when bombarded by radiation, ionize and become electrical conductors make them useful in:
a. X-ray transformers
b. X-ray tubes
c. masks
d. radiation detection equipment
A
d. radiation detection equipment
8
Q
- The velocity of electrons striking the target in an X-ray tube is a function of the:
a. atomic number of the cathode material
b. atomic number of the filament material
c. voltage difference between the cathode and anode
d. current flow in the rectifier circuit
A
c. voltage difference between the cathode and anode
9
Q
- The uneven distribution of developed grains within the emulsion of a processed X-ray film causes the subjective impression of:
a. graininess
b. streaks
c. spots
d. white scum
A
a. graininess
10
Q
- Co-60 is reported to have a half-life of 5.3 years. By how much should exposure time be increased (over that used initially to produce excellent radiographs when the Co-60 source was new) when the source is two years old?
a. no change in exposure time is needed
b. exposure time should be about 11 percent longer
c. exposure time should be about 31 percent longer
d. exposure time should be about 62 to 100 percent longer
A
c. exposure time should be about 31 percent longer
11
Q
- A source of Ir-192, whose half-life is 75 days,
provides an optimum exposure of a given test object today in a period of 20 minutes. Five months from now, what exposure time would be required for the same radiographic density, under similar exposure conditions?
a. 10 minutes
b. 20 minutes
c. 1 hour and 20 minutes
d. 6 hours
A
c. 1 hour and 20 minutes
12
Q
- Of the following, the source providing the most penetrating radiation is:
a. Co-60
b. 220 kVp X-ray tube
c. 15 Me V X-ray betatron
d electrons from Ir-192
A
c. 15 Me V X-ray betatron
13
Q
- The gamma ray intensity at 30 cm (1 ft) from a 37 GBq (1 Ci) source of radioactive Co-60 is nearest to:
a. 15 roentgens per hour
b. 1 000 roentgens per hour
c. 1 roentgen per minute
d. 10 milliroentgens per day
A
a. 15 roentgens per hour
14
Q
- The focal spot in an X-ray tube:
a. is inclined at an angle of 30º from the normal to the tube axis
b. is maintained at a high negative voltage during operations
c. should be as large as possible to ensure a narrow beam of primary radiation
d. should be as small as possible without unduly shortening the life of the tube
A
d. should be as small as possible without unduly shortening the life of the tube
15
Q
- In an X-ray tube, the filament and focusing cup are the two essential parts of the:
a. anode
b. cathode
c. rectifier
d. X-ray transformer
A
b. cathode
16
Q
- The quantity of radiation which will produce, by means of ionization, one electrostatic unit of electricity in 0.001293 g of dry air is known as a:
a. millicurie
b. gamma
c. roentgen
d. curie
A
c. roentgen
17
Q
- The specific activity of an isotopic source is usually measured in:
a. million electron volts (Me V)
b. curies per gram (Ci/g)
c. roentgens per hour (R/h)
d. counts per minute (cpm)
A
b. curies per gram (Ci/g)
18
Q
- Which of the following isotopes has the longest half-life?
a. Tm-170
b. Co-60
c. Ir-192
d. Cs-137
A
d. Cs-137
19
Q
- The primary form of energy conversion when electrons strike a target in an X-ray tube results in the production of:
a. primary X-rays
b. secondary X-rays
c. short wavelength X-rays
d. heat
A
d. heat
20
Q
- The slope of a straight line joining two points of specified densities on a characteristic curve of a film is known as the:
a. speed of the curve
b. latitude
c. average gradient
d. density
A
c. average gradient
21
Q
- An X-ray film having wide latitude also has, by definition:
a. poor definition
b. low contrast
c. high speed
d. none of the above
A
b. low contrast
22
Q
- The purpose for circulating oíl in some types of X-ray tubes is to:
a. lubricate moving parts
b. absorb secondary radiation
c. decrease the need for high current
d. dissipate heat
A
d. dissipate heat
23
Q
- An X-ray tube with a small focal spot is considered better than one with a large focal spot when it is desired to obtain:
a. greater penetrating power
b. better definition
c. less contrast
d. greater film density
A
b. better definition
24
Q
- One method of reducing radiographic contrast is to:
a. increase the distance between the radiation source and the object
b. decrease the distance between the object and the film
c. decrease the wavelength of the radiation used
d. increase development time within manufacturer’s recommendations
A
c. decrease the wavelength of the radiation used
25
25. Thin sheets of lead foil in intimate contact with X-ray film during exposure increase film density because they:
a. fluoresce and emit visible light which helps expose the film
b. absorb the scattered radiation
c. prevent backscattered radiation from fogging the film
d. emit electrons when exposed to X-and gamma radiation which help darken the film
d. emit electrons when exposed to X-and gamma radiation which help darken the film
26
26. X-ray tubes are often enclosed in a shockproof casing in order to:
a. dissipate heat
b. protect the operator from high-voltage shock
c. shield the tube from secondary radiation
d. increase the efficiency of the rectifier
b. protect the operator from high-voltage shock
27
27. An X-ray tube is rated for a maximum of 250 kVp. This tube may be operated at a maximum of:
a. 250 000 V peak voltage
b. 250 kV effective voltage
c. 250 000 000 V rms voltage
d. 250 kV average voltage
a. 250 000 V peak voltage
28
28. A voltage selector consisting of an iron core
transformer with a single winding having a series of taps at various points on the winding is called:
a. a high-voltage transformer
b. a filament transformer
c. an autotransformer
d. a power transformer
c. an autotransformer
29
29. In X-ray radiography, alternating current must be changed to pulsating direct current in order to satisfy the need for unidirectional current. This change may be accomplished by:
a. transformers
b. rectifiers
c. anodes
d. cathodes
b. rectifiers
30
30. When radiographing to the 2-2T quality level, an ASTM penetrameter for 63 mm (2.5 in.) steel has a thickness of:
a. 13 mm (0.5 in.)
b. 64 μm (2.5 mils)
c. 127 μm (5 mils)
d. 1270 μm (50 mils)
d. 1270 μm (50 mils)
31
31. Valve tubes are used in X-ray equipment to:
a. provide necessary rectification
b. activate and deactivate the X-ray tube
c. heat the filaments in the X-ray tube
d. adjust the size of the target
a. provide necessary rectification
32
32. A good Co-60 radiograph is made on a 76 mm (3 in.) steel casting using an exposure time of 10 minutes and a source-to-film distance of 91 cm (36 in.). If it is necessary to change the source-to-film distance to 61 cm (24 in.), what exposure time would produce a similar radiograph if all other conditions remain the same?
a. 1.6 minutes
b. 4.4 minutes
c. 6.4 minutes
d. 8.8 minutes
b. 4.4 minutes
33
33. When sharp, black, bird-foot shaped marks which are known not to correspond with any discontinuities appear at random on radiographs, they are probably caused by:
a. prolonged development in old developer
b. exposure of the film by natural cosmic ray showers during storage
c. static charges caused by friction
d. inadequate rinsing after fixing
c. static charges caused by friction
34
34. The adjustment of tube current in conventional X-ray tube circuits is made by:
a. adjusting the filament heating current
b. adjusting the target-to-cathode distance
c. inserting resistance in the anode lead
d. opening the shutter on the X-ray tube port
a. adjusting the filament heating current
35
35. In comparison with lower-voltage radiographs, high-energy radiographs show:
a. greater contrast
b. greater latitude
c. greater amounts of scatter radiation relative to primary beam intensity
d. none of the above
b. greater latitude
36
36. Filters used at the port of the X-ray tube:
a. intensify the X-ray beam by contributing secondary radiation
b. filter short wavelength X-ray beams to provide "softer" radiation
c. provide the most readily adjusted means of modifying X-ray intensity
d. filter out "soft" radiation to provide a more homogeneous X-ray beam
d. filter out "soft" radiation to provide a more homogeneous X-ray beam
37
37. An ASTM penetrameter for use when inspecting a 13 mm (0.5 in.) thick steel plate to the 2-2T quality level using a 41 cm (16 in.) source-to-film distance would be made of:
a. 127 μm (5 mil) thick aluminum
b. 1270 μm (50 mil) thick aluminum or steel
c. 254 μm (10 mil) thick steel
d. 51 μm (2 mil) strip of any metallic material
c. 254 μm (10 mil) thick steel
38
38. Filters placed between the X-ray tube and specimen tend to reduce scatter radiation undercutting the specimen by:
a. absorbing the longer wavelength components of the primary beam
b. absorbing the shorter wavelength components of the primary beam
c. absorbing backscatter radiation
d. decreasing the intensity of the beam
a. absorbing the longer wavelength components of the primary beam
39
39. Besides serving as a filter, screens of high atomic numbers, such as lead and lead antimony, also:
a. decrease the source-to-film distance needed for a proper radiograph
b. provide some image intensifying action
c. permit the use of higher speed film
d. decrease the graininess in a radiograph
b. provide some image intensifying action
40
40. The range of thickness over which densities are obtained that are satisfactory for interpretation is a measure of the:
a. subject contrast of a radiograph
b. sensitivity of a radiograph
c. latitude of a radiograph
d. definition of a radiograph
c. latitude of a radiograph
41
41. Almost all gamma radiography is performed with:
a. natural isotopes
b. Ir-192 or Co-60
c. radium
d. Tm-170
b. Ir-192 or Co-60
42
42. The amount of unsharpness or blurring of a radiograph is:
a. directly proportional to the object-to-film distance and inversely proportional to the size of the focal spot
b. directly proportional to the size of the focal spot and inversely proportional to the source-to-object distance
c. inversely proportional to the object-to-film distance and directly proportional to the source-to-object distance
d. inversely proportional to the size of the focal spot and the object-to-film distance
b. directly proportional to the size of the focal spot and inversely proportional to the source-to-object distance
43
43. Images of discontinuities close to the source side of the specimen become less clearly defined as:
a. source-to-object distance increases
b. the thickness of the specimen increases
c. the size of the focal spot decreases
d. the thickness of the specimen decreases
b. the thickness of the specimen increases
44
44. The inherent filtration of an X-ray tube is a function of the:
a. thickness and composition of the X-ray tube port
b. voltage setting of the instrument
c. source-to-object distance
d. material used as a target
a. thickness and composition of the X-ray tube port
45
45. X-ray films with large grain size:
a. will produce radiographs with better definition than film with small grain size
b. have slower speeds than those with a relatively small grain size
c. have higher speeds than those with a relatively small grain size
d. will take longer to expose properly than film with relatively small grain size
c. have higher speeds than those with a relatively small grain size
45
46. As the effective energy of the radiation increases up to about 250 kV:
a. film graininess increases
b. film graininess decreases
c. radiographic definition increases
d. film speed decreases
a. film graininess increases
45
47. The specific activity of Co-60 depends on the:
a. time the material has been in the reactor
b. atomic number of the material
c. gamma ray flux to which it was exposed
d. Young' s modulus value of the material
a. time the material has been in the reactor
45
48. The most commonly used target material in an X-ray are:
tube is:
a. copper
b. carbon
c. carbide
d. tungsten
d. tungsten
46
49. The purpose for including a disc-shaped target that rotates rapidly during operation in some X-ray tubes is to:
a. increase the intensity of X-radiation
b. decrease the voltage needed for a specific quality of radiation
c. increase the permissible load
d. none of the above
c. increase the permissible load
46
50. A device which is basically a combination of magnet and transformer designed to guide and accelerate electrons in a circular orbit to very high energies is called a:
a. electrostatic belt generator
b. linear accelerator
c. betatron
d. toroidal electromagnetic type X-ray tube
c. betatron
47
51. Two isotropic sources of a given strength have two different specific activity values. The source with the higher specific activity value will:
a. have a smaller physical size than the source with a
lower specific activity
b. have a shorter half-life than the source with a
lower specific activity
c. produce harder gamma rays than the source with a
lower specific activity
d. have a larger physical size than the source with the
lower specific activity
a. have a smaller physical size than the source with a
lower specific activity
48
52. A gas-filled region located in an electrical field
created by electrodes across which a potential
difference is applied forms the major portion of:
a. a low voltage X-ray tube
b. a megger
c. a hot cathode X-ray tube
d. an ionization chamber
d. an ionization chamber
49
53. Two serious obstacles to high-intensity fluoroscopy are:
a. the inability to reproduce results and the need for
periodic replacement of screens
b. the limited brightness and large grain size of
fluoroscopic screens
c. cost and slow speed
d. the need for using long wavelength X-rays and the
lack of X-ray intensity associated with this method
b. the limited brightness and large grain size of fluoroscopic screens
50
54. In general, the quality of fluoroscopic equipment is
best determined by:
a. densitometer readings
b. penetrameter sensitivity measurements
c. discontinuity area measurements
d. reference standards
b. penetrameter sensitivity measurements
51
55. In fluoroscopic testing, a fundamental difficulty is the relative low brightness level of the images. One method for increasing brightness utilizes one of the following which converts light energy from the initial phosphor surface to electrons which are accelerated and focused onto a smaller fluorescent screen.
a. betatron
b. electron amplifier
c. image amplifier or intensifier
d. electrostatic belt generator
c. image amplifier or intensifier
52
56. A general rule governing the application of the geometric principies of shadow formation states that the:
a. X-rays should proceed from as large a focal spot as
other considerations will allow
b. distance between the radiation source and the
material examined should be as small as practical
c. film should be as far as possible from the object
being radiographed
d. central ray should be as nearly perpendicular to the
film as possible to preserve spatial relationships
d. central ray should be as nearly perpendicular to the
film as possible to preserve spatial relationships
53
58. The radiographic absorption of a material will tend to become less dependent upon the composition of the material when:
a. the kilovoltage is increased
b. the source-to-film distance is decreased
c. the kilovoltage is decreased
d. a filter is used
a. the kilovoltage is increased
54
57. In order to utilize the principies of geometric
enlargement (placing the film at a distance from the
specimen):
a. the source-to-specimen distance must be half the
source-to-film distance
b. the source of radiation must be extremely small
c. a magnetic focusing coil must be used near the
port of the X-ray tube
d. the specimen must be of uniform thickness
b. the source of radiation must be extremely small
55
59. The formula (milliamperes x time)+distance2 is:
a. used to calculate film gradient
b. the reciprocity law
c. used to determine radiographic contrast
d. the exposure factor
d. the exposure factor
56
60. The load that can be handled by an X-ray tube focal spot is governed by:
a. the composition of the cathode
b. the size of the focal spot and the efficiency of the
cooling system of the anode
c. the distance from the anode to the cathode
d. the high-voltage waveform
b. the size of the focal spot and the efficiency of the
cooling system of the anode
57
61. X-ray exposure holders and cassettes often
incorporate a sheet of lead foil in the back which is not in intimate contact with the film. The purpose of
this sheet of lead foil is:
a. to act as an intensifying screen
b. to protect the film from backscatter
c. both a and b
d. neither a nor b
b. to protect the film from backscatter
58
62. A lead sheet containing a pinhole may be placed
halfway between the X-ray tube and the film in order
to:
a. determine the approximate size of the focal spot
b. measure the intensity of the central ray
c. filter scatter radiation
d. soften the X-radiation
a. determine the approximate size of the focal spot
59
63. In certain cases, it may be advantageous to pack lead shot around a specimen. The purpose for doing this is to:
a. prevent movement of the specimen
b. increase the subject contrast
c. generate smaller wavelength X-radiation
d. decrease the effect of scattered radiation
undercutting the specimen
d. decrease the effect of scattered radiation
undercutting the specimen
60
64. When radiographing steel with a thickness less than 25 mm (1 in.):
a. Co-60 would give greater radiographic sensitivity
than a 250 kV X-ray machine
b. a 250 kV X-ray machine would give greater
radiographic sensitivity than Co-60
c. the use of fluorescent screens would result in a
radiograph of better quality than would lead foil
screens
d. the use of lead foil screens will require a shorter
exposure time than will fluorescent screens
b. a 250 kV X-ray machine would give greater
radiographic sensitivity than Co-60
61
65. A radiograph made with an exposure of 12 mA per minute has a density of 0.8 in the region of maximum interest. It is desired to increase the density to 2.0 in this area. By reference to a characteristic curve of the film, it is found that the difference in log E, between
a density of 0.8 and 2.0 is 0.76. The antilogarithm of log 0.76 is 5.8. What must the new exposure time be to produce a radiograph with a density of 2.0?
a. 9.12 mA per minute A.19.17
b. 21.12 mA per minute
c. 69.6 mA per minute
d. 16 mA per minute
c. 69.6 mA per minute
62
66. The absorption of radiation by a material varies:
a. directly with the square of the distance from the source
b. with the thickness of the material
c. inversely with the amount of scattering in the
material
d. in an approximately exponential manner with the thickness of the material
d. in an approximately exponential manner with the thickness of the material
63
67. In the microradiographic technique:
a. soft X-rays are usually used
b. a kilovoltage range of 5-50 kV is usually used
c. the photographic material is often finer grained
than an ordinary X-ray film
d. all of the above
d. all of the above
64
68. In order for a radiograph to have a penetrameter sensitivity of 2-2T or better:
a. the radiographic procedure has to be able to differentiate a 2 percent difference in specimen
thickness
b. the radiographic procedure must be able to define the 2T hole in a penetrameter which is 2 percent of the thickness of the specimen
c. the radiograph must be able to distinguish a discontinuity with a length equivalent to 2 percent of the specimen thickness
d. none of the above
b. the radiographic procedure must be able to define the 2T hole in a penetrameter which is 2 percent of the thickness of the specimen
65
69. For practical purposes, the shape of the characteristic curve of an X-ray film is:
a. independent of the type of film used
b. independent of the quality of X- or gamma radiation
c. drastically changed when the quality of X-ray radiation is changed
d. primarily determined by the subject contrast
b. independent of the quality of X- or gamma radiation
66
70. The term which describes the total absorption of the useful beam caused by the X-ray tube wall, the wall of the tube housing, and any material between the the tube and housing is:
a. stray absorption
b. source absorption
c. characteristic filtration
d. inherent filtration
d. inherent filtration
67
71. The interval between the time a film is placed in a fixer solution and the time when the original diffuse, yellow milkiness disappears is known as:
a. clearing time
b. fixing time
c. hardening time
d. oxidation time
a. clearing time
68
72. Improper geometric factors, poor contact between film and lead foil screens, and graininess of film are possible causes of:
a. high film density
b. poor definition
c. fogged film
d. low film density
b. poor definition
69
73. In fluoroscopy, the most common way to minimize operator fatigue is to:
a. equip operators with special glasses
b. place a filter over the viewing screen
c. vary the intensity of the background light
d. change operators periodically
d. change operators periodically
70
74. Which of the following X-ray generators would produce the narrowest cone of X-radiation?
a. 10 MeV
b. 15 Me V
c. 25 Me V
d. 1 MeV
c. 25 Me V
71
75. A radiograph is taken at a voltage of 500 kV. If the voltage is increased with a resultant increase in the energy of radiation, while all other conditions remain
the same:
a. the graininess of the film will increase radiation significantly if a high-speed film is used
b. the graininess of the film will decrease significantly if a low-speed film is used
c. the graininess of the film will increase significantly if a Class I film is used
d. there will be little significant change in the
graininess of the film
d. there will be little significant change in the
graininess of the film
72
76. A radiograph of a steel weldment is made using a 15 MeV betatron. When the radiograph is developed, there is an overall film mottling. A possible cause for such mottling is:
a. incorrect exposure time
b. excessive object-to-film distance
c. failure to use a lead screen during exposure
d. excessive exposure to ultraviolet rays
c. failure to use a lead screen during exposure
73
77. A basic difference between a radiograph and a fluoroscopic image is:
a. the fluoroscopic image is more sensitive
b. the fluoroscopic image is a positive whereas the
radiograph is a negative transparency
c. the fluoroscopic image is brighter
d. there is no basic difference between the two
b. the fluoroscopic image is a positive whereas the
radiograph is a negative transparency
74
78. Which of the following factors will not materially influence the image density of a radiograph?
a. the type of film used
b. the size of the film
c. the total amount of radiation emitted by the X-ray
or gamma ray source
d. the intensifying action of the screen
b. the size of the film
75
79. A 1000 kVp X-ray machine used in conjunction with a lead foil screen has an approximate practical thickness limit of:
a. 38 mm (1.5 in.) of steel or its equivalent
b. 76 mm (3 in.) of steel or its equivalent
c. 127 mm (5 in.) of steel or its equivalent
d. 41 cm (16 in.) of steel or its equivalent
c. 127 mm (5 in.) of steel or its equivalent
76
80. Because of geometrical factors such as source size, source-to-specimen distance, and specimen-to-film distance, there can be a lack of perfect sharpness at the edges of indications. The unsharpness caused by geometrical factors may be referred to as the:
a. astigmatic effect
b. penumbral shadow
c. focus variation
d. none of the above
b. penumbral shadow
77
81. Two factors which greatly affect the suitability of the target material in an X-ray tube are:
a. tensile strength and yield strength
b. melting point and magnetic strength
c. electrical resistance and tensile strength
d. atomic number and melting point
d. atomic number and melting point
78
82. The reason the exposure time must be increased by a factor of four when the source-to-film distance is doubled is that:
a. the intensity of radiation decreases at an exponential rate when the source-to-film distance is increased.
b. the quality of radiation is inversely proportional to the square root of the distance from the source to the film.
c. the intensity of radiation is inversely proportional to the square of the distance from the source to the film.
d. the scattered radiation effect is greater as the source-to-film distance increases.
c. the intensity of radiation is inversely proportional to the square of the distance from the source to the film.
79
83. The most important factor for determining the amount of X-ray absorption of a specimen is the:
a. thickness of the specimen
b. density of the specimen
c. atomic number of the material
d. Young' s modulus of the material
c. atomic number of the material
80
84. The approximate radiographic equivalent factors for steel and copper at 220 kV are 1.0 and 1.4 respectively. If it is desirable to radiograph a 13 mm (0.5 in.) plate of copper, what thickness of steel would require about the same exposure characteristics?
a. 18 mm (0.7 in.) of steel
b. 6 mm (0.35 in.) of steel
c. 36 mm (1.4 in.) of steel
d. 25 mm (1 in.) of steel
a. 18 mm (0.7 in.) of steel
81
85. Which of the following technique variables is most
commonly used to adjust subject contrast?
a. source-to-film distance
b. milliamperage
c. kilovoltage
d. focal point size
c. kilovoltage
82
86. Films that are left between lead screens too long in a high-temperature and high-humidity atmosphere may:
a. show increased speed but decreased quality characteristics
b. become fogged
c. become mottled
d. show tree-shaped light areas in the finished
radiograph
b. become fogged
83
87. The quantitative measure of film blackening is referred to as:
a. definition
b. photographic density
c. film contrast
d. radiographic contrast
b. photographic density
84
88. A curve that relates density with the logarithm of exposure or of relative exposure is called:
a. a sensitivity curve
b. a density-exposure curve
c. an H&D curve
d. X-ray intensity curve
c. an H&D curve
85
89. Subject contrast is affected by:
a. thickness differences in specimen
b. radiation quality
c. scattered radiation
d. all of the above
d. all of the above
86
90. Which of the following instruments would exhibit the best sensitivity and most likely be used to detect small leaks in a radiation barrier?
a. a film badge
b. a fountain pen type of ionization chamber
c. a Geiger counter
d. a dosimeter
b. a fountain pen type of ionization chamber
87
91. At voltages above 400 kV, the use of lead to provide protection may present serious problems. If this is a serious problem, which of the following materials would most likely be used as a substitute?
a. aluminum
b. concrete
c. steel
d. boron
b. concrete
88
92. A qualitative term often used to indicate the size of the smallest detail that can be seen in a radiograph is:
a. radiographic sensitivity
b. radiographic definition
c. radiographic contrast
d. subject contrast
a. radiographic sensitivity
89
93. The slope (steepness) of a characteristic curve is a measure of:
a. subject contrast
b. radiographic definition
c. radiographic contrast
d. film contrast
d. film contrast
90
94. A special radiographic method requiring two radiographs taken during separate exposures from two different positions to give the visual impression of a three-dimensional display when viewed in an optical device simultaneously is called:
a. fluoroscopy
b. xeroradiography
c. stereoradiography
d. parallel radiography
c. stereoradiography
91
95. The depth of a discontinuity can be estimated by making two exposures on a single film from two different positions of the X-ray tube. The depth of the discontinuity is computed from the shift in the shadow of the discontinuity with respect to the images of fixed markers on the front and back of the specimen. The method is called:
a. stereoradiography
b. xeroradiography
c. fluoroscopy
d. the parallax method of depth location
d. the parallax method of depth location
92
96. Constant agitation of the developer during the development process by means of mechanical stirrers or circulating pumps may:
a. speed the developing cycle
b. help replenish the developer
c. cause undesirable, preferential flow of developer along certain paths
d. cause reticulation
c. cause undesirable, preferential flow of developer along certain paths
93
97. The activity of the fixer diminishes after being used for a period of time because the:
a. active ingredients evaporate
b. active ingredients are absorbed by the radiograph
c. fixer solution accumulates soluble silver salts
d. active ingredients settle to the bottom of the tank
c. fixer solution accumulates soluble silver salts
94
98. In processing radiographs, the hourly flow of water in the wash tank should be:
a. 2-3 times the volume of the tank
b. 4-8 times the volume of the tank
c. at least 151 L ( 40 gal) per hour
d. varied continuously in proportion to the number of radiographs being developed
b. 4-8 times the volume of the tank
95
99. A zinc cadmium sulfide fluoroscopic screen that is continually exposed to bright daylight, sunlight, or other sources of ultraviolet radiation will:
a. need to be recharged to regain its original
fluorescence
b. become discolored and lose some of its brilliance
c. require a higher kilovoltage of the X-ray generator to produce a satisfactory image
d. all of the above
b. become discolored and lose some of its brilliance
96
100. Increasing the X-ray or gamma ray energy will:
a. significantly decrease the average gradient of a characteristic curve
b. significantly increase the average gradient of a characteristic curve
c. increase the slope of a characteristic curve
d. have little effect on the shape of a characteristic
curve
d. have little effect on the shape of a characteristic
curve
97
101. As the development time increases:
a. the characteristic curve grows steeper and moves to the left
b. the characteristic curve grows steeper and moves to the right
c. the characteristic curve remains the same in shape but moves to the left
d. there is little effect on the characteristic curve
a. the characteristic curve grows steeper and moves to the left
98
102. A distinctive characteristic of high-voltage
radiography is that:
a. it results in comparatively high subject contrast
b. it results in comparatively high radiographic
contrast
c. it is applicable to comparatively thick or highly absorbing specimens
d. all of the above are distinctive characteristics of high-voltage radiography
c. it is applicable to comparatively thick or highly absorbing specimens
99
103. Lead screens are used for almost all exposures when using:
a. the fluoroscopic technique
b. low-voltage radiography
c. high-voltage radiography
d. xeroradiography
c. high-voltage radiography
100
104. Which of the following glasses would most likely be used as an X-ray barrier window on fluoroscopic equipment?
a. Pyrex™
b. lead glass
c. optical glass
d. barium oxide glass
b. lead glass
100
105. The maximum practical speed of scanning a test object for conventional fluoroscopic inspection has been estimated to be about:
a. 18 cm (7 in.) per s
b. 25 mm (1 in.) per s
c. 30 cm (12 in.) per s
d. 76 mm (3 in.) per s
d. 76 mm (3 in.) per s
101
106. When other operating conditions are held constant, a change in tube current causes a change in radiation intensity emitted from an X-ray tube, the intensity being approximately proportional to tube current. What is the primary factor that prevents this from being exactly proportional?
a. the voltage and voltage waveform of an X-ray
machine transformer varíes with load
b. wavelength changes are not exactly proportional
c. current cannot be changed at a linear rate
d. scatter radiation does not vary at a proportional rate
a. the voltage and voltage waveform of an X-ray
machine transformer varíes with load
101
107. When viewing a radiograph, an image of the back of the cassette superimposed on the image of the specimen is noted. This is most likely due to:
a. undercut
b. overexposure
c. the X-ray intensity was too high
d. backscatter
d. backscatter
102
108. The half-value layer of lead for Co-60 is
approximately 13 mm (0.5 in.). If the radiation level on the source side of a 38 mm (1.5 in.) lead plate is 64 R/h, the radiation level on the opposite side is:
a. 8 R/h
b. 211 13 R/h
c. 10213 R/h
d. 32 R/h
a. 8 R/h
103
109. Which of the following is not a factor in determining subject contrast?
a. nature of the specimen
b. the radiation quality used
c. type of film used
d. intensity and distribution of the scattered radiation
c. type of film used
104
110. If an exposure time of 60 s and a source to-film distance of 1.2 m (4 ft) is necessary for a particular exposure, what exposure time would be needed for an equivalent exposure if the source-to-film distance is changed to 1.8 m (6 ft)?
a. 27 s
b. 49 s
c. 135 s
d. 400 s
c. 135 s
105
111. Developer solution should be discarded when the quantity of replenisher added equals:
a. the original quantity of developer
b. 2-3 times the original quantity of developer
c. 5-6 times the original quantity of developer
d. 10 times the original quantity of developer
b. 2-3 times the original quantity of developer
106
113. A 250 kVp X-ray machine used in conjunction with a lead foil screen has an approximate practical thickness limit of:
a. 38 mm (1.5 in.) of steel or its equivalent
b. 51 mm (2 in.) of steel or its equivalent
c. 15 cm (6 in.) of steel or its equivalent
d. 19 cm (7.5 in.) of steel or its equivalent
b. 51 mm (2 in.) of steel or its equivalent
106
112. If a specimen is radiographed at 40 kV and again at 50 kV with time compensation to give the radiographs the same density, which of the following statements would be true?
a. the 40 kV exposure would have a lower contrast and a greater latitude than the 50 kV exposure
b. the 40 kV exposure would have a higher contrast and greater latitude than the 50 kV exposure
c. the 50 kV exposure would have a lower contrast and a greater latitude than the 40 kV exposure
d. the 50 kV exposure would have a higher contrast and greater latitude than the 40 kV exposure
c. the 50 kV exposure would have a lower contrast and a greater latitude than the 40 kV exposure
107
114. The degree of concentration of the radioactive material in a gamma ray source is referred to as the:
a. specific activity of the source
b. quality of the source
c. atomic weight of the source
d. half-life of the source
a. specific activity of the source
108
115. In million-volt radiography, filtration at the tube:
a. increases the generation of short wavelength
X-rays
b. decreases the generation of short wavelength X-rays
c. improves the radiographic quality by decreasing scatter radiation
d. offers no improvement in radiographic quality
d. offers no improvement in radiographic quality
109
116. Film selection for an X-ray exposure depends on:
a. the thickness of the part
b. the material of the specimen
c. the voltage range of the X-ray machine
d. all of the above
d. all of the above
110
117. While using an X-ray tube for radiography, the operator wants to increase the radiation intensity. To do so, the:
a. kilovoltage should be lowered
b. tube current should be increased
c. test specimen should be moved further from the film
d. tube current should be decreased
b. tube current should be increased
111
118. Lead screens are put in direct contact with the film to:
a. increase the photographic action on the film
b. absorb the longer wavelength scattered radiatíon
c. intensify the photographic effect of the primary more than the scattered radiation
d. do all of the above
d. do all of the above
111
119. Because of geometrical factors such as source size, source-to-specimen distance, and specimen-to-film distance, there can be a lack of perfect sharpness at the edges of indications. The unsharpness caused by these factors may be called the:
a. astigmatic effect
b. penumbral shadow
c. focus variation
d. none of the above
b. penumbral shadow
111
120. The main purpose of the X-ray generator controls on the equipment is to:
a. maintain the direction and width of the X-ray beam
b. enable the operator to obtain the intensity, quality, and duration of exposure desired
c. allow the operator to adjust Film Focal Distance remotely
d. change alternating current to increase X-ray
intensity
b. enable the operator to obtain the intensity, quality, and duration of exposure desired
112
121. Fluoroscopic screens, as mounted and used, are easily damaged by which of the following?
a. washing with a soft cotton cloth
b. exposure to ultraviolet radiation or sunlight
c. poor handling
d. X-radiation
b. exposure to ultraviolet radiation or sunlight
113
122. When X-rays, gamma rays, light, or electrons strike the photographic emulsion, a change takes place in the silver halide crystals. This change is called:
a. photographic density
b. photographic sensitivity
c. latent image
d. characteristic curve
c. latent image
114
123. If 3.7 GBq (1 Ci) of lr-192 produces a dose rate of 5 900 mR/h at 0.3 m (1 ft), how many mR will 3 700 GBq (10 Ci) produce at the same distance?
a. 590
b. 590 000
c. 59
d. 59 000
d. 59 000
115
124. With respect to quality, what three factors must be considered in selecting a source-to-film distance?
a. source activity, type of film, type of screens
b. source activity, size of film, thickness of material
c. source size, source activity, specimen-to-film
distance
d. source size, specimen thickness, geometric
unsharpness
d. source size, specimen thickness, geometric
unsharpness
116
125. On a radiograph of a pipe weld, there is a very light irregularly-shaped small image in the weld. This image would most likely be due to the presence of:
a. porosity
b. slag inclusion
c. tungsten inclusion
d. inadequate buildup
c. tungsten inclusion
117
126. A larger physical size source may produce an equivalent quality radiograph if:
a. the source-to-film distance is increased
b. more backing lead is used
c. a faster film is used
d. exposure time is decreased
a. the source-to-film distance is increased
118
127. A light image of a backing "B" on a processed radiograph is probably caused by:
a. excessive density
b. backscatter
c. kilovoltage set too low
d. poor film handling
b. backscatter
119
128. Co-59 becomes Co-60 when it is placed in a nuclear reactor where it captures:
a. an electron
b. a neutron
c. a proton
d. contamination
b. a neutron
120
129. When a faster speed film is substituted for a slower one to improve the economics of the exposure, which of the following conditions occur?
a. the film must receive special processing
b. the definition will improve
c. the image resolution will be reduced
d. none of the above will be experienced
c. the image resolution will be reduced
121
130. For a given change in the radiation exposure, film contrast is the inherent ability to show:
a. a difference in density
b. no graininess
c. grammess
d. no appreciable change in density
a. a difference in density
122
131. The ability of a material to block or partially block the passage of X-rays and gamma rays is called:
a. penetration
b. absolution
c. absorption
d. latitude
c. absorption
123
132. Source size, specimen thickness, and source-to specimen distance are the three factors that determine the:
a. density of the radiograph
b. exposure of the radiograph
c. film size
d. unsharpness recorded on the radiograph
d. unsharpness recorded on the radiograph
124
133. The range of specimen thicknesses that can be adequately recorded on the radiograph is called:
a. sensitivity of the radiograph
b. latitude of the radiograph
c. accuracy of the radiograph
d. intensity of the source
b. latitude of the radiograph
125
134. Approximately how long would it take for a 370 GBq (10 Ci) Co-60 source to decay to 93 GBq (2.5 Ci)?
a. 5.3 days
b. 5.3 years
c. 10.6 years
d. none of the above
c. 10.6 years
126
135. The "photoelectric" effect involves:
a. the visible electromagnetic spectrum
b. an electric camera
c. complete absorption of a photon
d. all of the above
c. complete absorption of a photon
127
136. Radiographic undercutting is caused by:
a. side scatter
b. poor geometry
c. lead screens
d. free electrons
a. side scatter
128
137. The developer solution is:
a. acid
b. alkaline
c. saline
d. colloidal
b. alkaline
129
138. A general rule governing the application of the geometric principies of shadow formation states that the:
a. X-rays should proceed from as large a focal spot as other considerations will allow
b. distance between the radiation source and the material examined should be as small as practical
c. film should be as far as possible from the object being radiographed
d. central ray should be as nearly perpendicular to the film as possible to preserve spatial relationships
d. central ray should be as nearly perpendicular to the film as possible to preserve spatial relationships
130
139. The half-life of radioactive Cs-137 is nearest to:
a. 36 days
b. 6 years
c. 30 years
d. 526 days
c. 30 years
131
140. The slope of the H&D curve of a radiographic film is called:
a. speed
b. latitude
c. gamma or gradient
d. density
c. gamma or gradient
132
141. The projected area of the target of an X-ray tube is called:
a. focal spot
b. focus
c. effective focal spot
d. geometric unsharpness
c. effective focal spot
133
142. The correct equation for determining geometric unsharpness Ug , is:
a. Ug= f/td
b. f= Ug=t/td
c. Ug =dt/f
d. Ug=ft/d
d=source-to-object distance
t=object-to-film distance
f=size of radiation source
d. Ug=ft/d
134
143. An exposure technique is established to obtain a 2.0 density using type "D" film and automatic processing at 27 ºC (81 ºF). In order to obtain comparable results using manual processing at 20 ºC (68 ºF) and 5-minute development time, it would be necessary for the original exposure time to be:
a. reduced by approximately 30 percent
b. increased by approximately 99 percent
c. increased by approximately 30 percent
d. reduced by approximately 99 percent
b. increased by approximately 99 percent
