Practice 1 Flashcards
1
Q
According to the Standard Model:
A. fundamental particles have an inner structure and can be divided.
B. quarks exist only as solitary particles.
C. electrons are made of quarks.
D. all visible matter in the universe is made of up quarks, down quarks, or electrons.
A
D
2
Q
When antimatter particles interact with matter, they:
A. form leptons.
B. form quarks.
C. mutually annihilate into pure energy.
D. create an antiparticle.
A
C
3
Q
Which of the following types of force carrier particles mediates the strong nuclear force that binds nuclei together?
A. Photons
B. Bosons
C. Gluons
D. Gravitons
A
C
4
Q
Which of the following statements is true of electron orbitals in an atom?
A.”‘S” represents the principal quantum number describing the size of the orbital.
B. The p-type orbital consists of four lobes arranged around the nucleus.
C. No known atom has more than 19 orbitals.
D. Only two electrons may occupy an orbital.
A
D
5
Q
In order for an electron to move from an outer orbital shell to one closer to the nucleus:
A. energy is lost and given up in the form of electromagnetic radiation.
B. energy is lost and given up in the form of particulate radiation.
C. energy must be supplied in an amount equal to the difference in binding energies between the two orbitals.
D. energy must be supplied in an amount equal to the binding energy of the inner orbital.
A
A
6
Q
ß particles most closely resemble a(n):
A. boson.
B. neutron.
C. proton.
D. electron.
A
D
7
Q
The of a particle, the greater is its linear energy transfer (LET).
A. greater the mass
B. greater the velocity
C. lesser the physical size
D. lesser the charge
A
A
8
Q
Which of the following forms of electromagnetic radiation has greater energy
than x rays?
A. infrared radiation
B. gamma (Y) rays
C. microwaves
D. radio waves
A
B
9
Q
The quantum theory of radiation has been successful in correlating experimental data on:
A. diffraction.
B. the production of x rays.
C. polarization.
D. refraction.
A
B
10
Q
High-energy photons such as x rays and y rays are typically characterized by their:
A. energy.
B. wavelength.
C. frequency.
D. magnitude.
A
A
11
Q
Within the x-ray tube:
A. electrons stream from a filament in the anode to a target in the cathode.
B. electrons stream from a filament in the cathode to a target in the anode.
C. photons stream from a filament in the anode to a target in the cathode.
D. photons stream from a filament in the cathode to a target in the anode.
A
B
12
Q
When x rays are being produced, the focusing cup:
A. is made of tungsten.
B. is positively charged
C. is a convex reflector.
D. contains the filament.
A
D
13
Q
More than % of the kinetic energy of electrons produced at the filament is converted to heat at the target.
A. 10
B. 50
C.90
D. 99
A
D
14
Q
The apparent size of the focal spot seen from a position perpendicular to the - beam is smaller than the actual focal spot size because the:
A. anode has many moving parts.
B. target is placed at an angle to the electron beam.
C. speed of the electrons is degraded by air in the x-ray tube.
D. focusing cup focuses the electrons into a narrow beam.
A
B
15
Q
The primary function(s) of the power supply of an x-ray machine is to:
A. provide a high-voltage current to heat the x-ray tube filament.
B. generate a low potential difference between the anode and the cathode.
C. provide a low-voltage current to heat the x-ray tube filament and generate a low potential difference between the a
anode and the cathode.
D. provide a low-voltage current to heat the X-ray tube filament and generate a high potential difference between the
anode and the cathode.
A
D
16
Q
When an x-ray machine is set to 70 kVp, the peak energy of electrons passing through the x-ray tube is:
boosted by the high-voltage transformer to 70 volts.
B. boosted by the high-voltage transformer to up to 70,000 volts.
C. reduced by the filament transformer to 70 volts.
D. reduced by the filament transformer to 70 milliamps.
A
C
17
Q
Current flows through the tube when the target anode is ___
and the filament is ___
A. positive; positive
B. negative; negative
C. positive; negative
D. negative; positive
A
C
18
Q
Which of the following statements is true regarding generation of x-ray pulses w/in an alternating current (AC)
X-ray tube?
A. During the inverse voltage or reverse bias portion of each cycle, the filament becomes negative and the target
becomes positive.
B. When an x-ray tube is powered with 60-cycle AC, 120 X rays are generated each second.
C. No x rays are generated during the inverse-voltage portion of the voltage cycle.
D. When photons produced by the filament strike the focal spot of the target, some of their energy converts to e-.
A
C
19
Q
For a full-wave rectified, high-frequency power x-ray machine:
A. the mean ene of the x-ray beam is lower than that from a conventional half-wave rectified machine operated at the
same voltage.
B. the images a for a given voltage setting and radiographic density will have a shorter contrast scale compared with
conventional x-ray machines.
C. at a given voltage setting and radiographic density, the pt receives a lower dose compared w/ conventional x-ray machines.
D. X rays will not be generated during the inverse voltage portion of the voltage cycle.
A
C
20
Q
A 15-impulse exposure is equivalent to ___
second for a conventional 60-cycle AC, half-wave rectified
x-ray machine.
A. 1
B. 0.5
C. 0.25
D. 0.125
A
C
21
Q
The duty cycle of a dental x-ray machine:
A. is the lifetime of the machine in years permitted by law before it must be replaced.
B. is the number of x-ray exposures permitted by law before it must be replaced.
C. reflects the frequency with which successive exposures can be made
D. describes the longest exposure time the tube can be energized for a range of voltages and tube current values with
risk of damage to the target from overheating.
A
C
22
Q
The primary source of radiation from an x-ray tube is caused by:
A. bremsstrahlung radiation.
B. characteristic radiation.
C. electrons from the filament directly hitting the nucleus of atoms in the target.
D. electrons from the filament directly hitting electrons in the target.
A
A
23
Q
The shape of the x-ray beam may be modified by altering the:
A. exposure duration.
B. exposure rate.
C. collimation.
D. intensity.
A
D
24
Q
When exposure time is doubled, the # of photons generated at all energies in the x-ray emission spectrum is:
A. the same, and the range of photon energies is unchanged.
B. the same, but the range of photon energies doubles.
C. doubled, but the range of photon energies is unchanged.
D. doubled, and the range of photon energies doubles as well.
A
C
25
A machine operating at 15 mA for 2 secs produces the same quantity of radiation when operated at 10 mA for ___
second(s).
A. 1
B. 2
C. 3
D. 4
C
26
Increasing the kVp will:
A. increase the number of photons generated, but neither their mean energy nor their maximal energy.
B. increase the number of photons generated and their mean energy, but not their maximal energy.
C increase the number of photons generated, their mean energy, and their maximal energy.
D. decrease the number of photons generated, but will increase their mean energy and their maximal energy.
C
27
Dental x-ray beams are usually collimated to a circle ___ in diameter.
A. 1.0 mm
B. 2.5 mm
C. 2.75 inches
D. 8 inches
C
28
The patient exposure resulting from a 1.0-second exposure using a 16-inch cone would be equivalent to a
-second exposure with an 8-inch cone if the kVp and mA are kept constant.
A. 0.25
B. 0.5
C. 1.0
D. 2.0
A
29
The primary means of dental x-ray beam attenuation is caused by:
A. coherent scattering.
B. photoelectric absorption.
C. Compton scattering.
D. pass-through with no interaction.
C
30
Photoelectric absorption occurs when a(n) ____ of the absorbing medium.
A. low-energy incident photon passes near the outer electron of an atom
B. photon interacts with an outer orbital electron
C. incident photon interacts with an electron in an inner orbital of an atom
D. photon interacts with the nucleus
C
31
_____ will result in the loss of an electron and ionization of the absorbing atom.
A. Coherent scattering, photoelectric absorption, and Compton scattering
B. Coherent scattering and photoelectric absorption, but not Compton scattering
C. Coherent scattering, but neither photoelectric absorption nor Compton scattering
D. Photoelectric absorption and Compton scattering, but not coherent scattering
D
32
As an x-ray beam passes through matter, the intensity of the beam ___
and the mean energy of the residual
beam ___
y preferential removal of low-energy photons.
A. increases; decreases
B. decreases; increases
C. decreases; decreases
D. increases; increases
B
33
When the energy of the incident photon is raised to match the binding energy of the 1s orbital electrons of the
absorber, the probability of photoelectric absorption ___
and the number of transmitted photons ___
A. increases; increases
B. increases; decreases
C. decreases; increases
D. decreases; decreases
B
34
The SI unit of exposure is the:
A. Gray.
B. Sievert.
C. air kerma.
D. Becquerel.
C
35
Which of the following statements is true concerning direct effects of radiation on living systems?
A. Exposure to radiation initiates a complex series of chemical changes in water that result in the radiolysis of water.
B. The energy of a photon or secondary electron ionizes biologic macromolecules.
C. The interaxn of hydrogen and hydroxyl free radicals w/ organic molecs results in formation of organic free radicals
D. Approximately two thirds of the biologic effects of x-ray exposure result from direct effects.
B
36
The primary cause of radiation-induced cell death, heritable (genetic) mutations, and cancer formation
(carcinogenesis) is damage to a cell's:
A. protein.
B. lipid.
C. carbohydrate.
D. DNA.
D
37
For deterministic effects:
A. the severity of the clinical effect is independent of dose.
B. it is an all-or-none response; an individual either has the effect or does not have the effect.
C. all individuals show the effect when the dose is above the threshold.
D. the frequency of the effect is proportional to the dose.
C
38
If a radiation-induced break occurs in Stage ___of mitosis, before the DNA in a chromosome has replicated, the
damage manifests as a break in both arms at the next mitosis.
A. G1
B. G1 or early S
C. mid- and late S or G2
D. G2
D
39
When a population of slowly dividing cells is irradiated, ___
are required for induction of ___
effects than when a rapidly dividing cell system is involved.
A. smaller doses and longer time intervals; deterministic
larger doses and shorter time intervals; stochastic
C. larger doses and longer time intervals; deterministic
D. larger doses and longer time intervals; stochastic
C
40
The most radiosensitive cells are those that have a:
A. low mitotic rate, undergo many future mitoses, and are most primitive in differentiation.
B. high mitotic rate, undergo many future mitoses, and are the most primitive in differentiation.
C. high mitotic
rate, undergo many future mitoses, and are the most advanced in differentiation.
D. low mitotic rate, undergo few future mitoses, and are the most advanced in differentiation.
B
41
Which of the following cells have the greatest radiosensitivity?
A. Striated muscle cells
B. Basal cells of oral mucous membrane
C. Parenchymal cells of liver, kidney, and thyroid
D. Fibroblasts
B
42
When considering deterministic effects, often a clinical threshold dose exists below which no adverse effects ar
seen. In all individuals receiving doses above the threshold level, the amount of damage is proportional to the dose.
A. Both statements are true.
B. Both statements are false.
C. The first statement is true; the second statement is false.
D. The first statement is false; the second statement is true.
A
43
Fractionation of a total x-ray dose into multiple small doses during radiation therapy:
A. decreases cellular repair of normal tissues, which are believed to have less capacity for recovery than tumor cells.
B. decreases cellular repair of normal tissues, which are believed to have a greater capacity for recovery than tumor
cells.
C. provides less tumor destruction than possible with a single large dose.
D. increases the mean oxygen tension in an irradiated tumor, rendering the tumor cells more radiosensitive.
D
44
Which of the following statements is true concerning the effects of irradiation on major salivary glands?
A. The stroma of the glands is rather radiosensitive, and the parenchyma is not.
B. The extent of reduced salivary flow is independent of dose.
C. The residual saliva is more viscous than usual because serous cells are more radiosensitive than mucous cells.
D. The small volume of saliva that is secreted usually has a pH value above normal.
C
45
Which of the following statements is true regarding radiation therapy to the jaws of children?
radiation therapy precedes dental calcification, it may destroy the tooth bud.
B. The eruptive mechanism of teeth is extremely sensitive to radiation; irradiated teeth w/ normal root anatomy will
not erupt.
C. Irradiated teeth with altered root form will not erupt.
D. Irradiation after calcification will accelerate general growth.
A
46
The best method of reducing radiation caries is:
A. prophylactic removal of all previously restored teeth.
B. daily application of a viscous topical 1% neutral sodium fluoride gel in custom-made applicator trays.
C. rinsing daily with an alcohol-containing mouthwash.
D. applying a fluoride-containing cavity varnish to all exposed root surfaces
B
47
Osteoradionecrosis is:
A. more common in the maxilla than in the mandible.
B. primarily caused by radiation-induced damage to the vasculature of the trabecular bone.
C. caused by an insult, such as infection in bone compromised by radiation therapy.
D. less likely to occur, the higher the radiation dose absorbed by the bone.
C
48
Whenever possible, patients who have had radiation therapy should avoid having intraoral radiographs during the
first ___ after completion of radiotherapy, to allow time for mucous membrane to heal.
A. 2 weeks
B. 2 months
C. 6 months
D. There is no minimal suggested time; the question is incorrect.
C
49
GI symptoms will be seen as a component of acute radiation syndrome when the dose is ___ Grays (Gy).
A. 2 to 4
B. 4 to 7
C. 7 to 15
D. 50
C
50
Which of the following blood cells are least affected by whole-body exposure to radiation 10 days after
exposure?
A. granulocytes
B. platelets
C. erythrocytes
D. lymphocytes
C
51
Which of the following organs has the lowest susceptibility to radiation-induced cancer?
A. lung
B. thyroid
C. stomach
D. salivary glands
D
52
Which of the following statements reflects basic principles of radiation genetics?
. Radiation causes increased induction of new mutations rather than increased frequency of spontaneous mutations.
B. There is evidence of a minimal threshold of mutations caused by radiation.
C. Dose rate is not important.
D. Males are much more radiosensitive than females.
D
53
The average annual effective dose of background radiation from cosmic and terrestrial sources is about 2.4
millisieverts (mSv) worldwide and 3.0 mSv in the United States because of:
A. fallout from the nuclear fuel cycle.
B. residual radiation from nuclear tests.
C higher radon levels.
D. nuclear
power plants.
C
54
The majority of the radiation exposure of the world's population from natural sources iS caused by:
decay or radioactive nuclides in the soil.
B. radon.
C. ingestion of radionuclides.
D. cosmic radiation.
B
55
Dental x-ray examinations are responsible for % of the average man-made exposure.
A. 90
B. 50
C. 10
D. less than
D
56
Dose limits from man-made sources for members of the general public, not occupationally exposed, have been
established at ___
% of that of occupationally exposed individuals.
A. 10
B. 25
C. 50
D. 75
A
57
The average dose for individuals occupationally exposed in the operation of dental x ray equipment is about_%
of the allowable exposure.
A. 40
B. 4.0
C. 0.4
D. 0.001
C
58
Which of the following statements is true regarding the risk for cancer being induced in humans as a result of
exposure to low doses of radiation?
A. The data for the cancer risk from radiation exposure involve exposures many times smaller than those involved
with dental radiology.
B. The incidence of cancer that may result from dental exposure is easily detected by direct measurement.
C. Radiation-induced cancers are clinically and histologically distinguishable from cancers induced by other causes.
D. The time between radiation exposure and the development of cancer may be years to decades, during which
individuals may be subjected to many other carcinogens.
D
59
The 33 uSv for a full-mouth x-ray series delivered to 1,000,000 people would result in about ___ additional cancer deaths over the lifetime of the exposed individuals.
A. 2
B. 20
C. 200
D. 2000
A
60
If a person living in an
average location in the United States had
complete mouth surveys made by optimized
techniques every year, he or she would incur only the same risk as a person living in Denver who was not exposed to
dental radiography.
A. 2
B. 4
C. 6
D. 14
D
61
The principle of ___
obligates the dentist to do more good than harm.
A. justification
B. optimization
C. dose limitation
D. ALARA
A
62
ALARA stands for:
A. as long as radiation applies.
B. as low as reasonably accountable.
C as low as reasonably achievable.
D. as low as radiology allows.
C
63
Which of the following statements is true of intraoral film speed?
A. D-speed film is the fastest speed.
B. F-speed film requires about 75% the exposure of D-speed film.
C. Film speed refers to the amount of exposure required to produce a standard amount of darkening.
D. F-speed film should not be used for dental radiographs.
C
64
Contemporary intensifying screens used in extraoral radiography:
A. primarily use the rare earth elements (thallium, niobium, terbium).
B. emit green light on interaction with x rays.
C. are made of calcium tungstate.
D. require doses of radiation that are significantly reduced by replacement with digital imaging.
B
65
When a 16-inch focal source-to-skin distance is contrasted with an 8-inch focal source-to-skin distance, use of
the long source-to-skin distance results in a(n) ___
in exposed tissue V because the beam is ___
divergent.
A. increase; more
B. increase; less
C. decrease; more
D. decrease; less
D
66
Federal guidelines and state regulations require that the x-ray beam used in intraoral radiography be collimated
so that the field of radiation at the patient's skin surface has a ___
when the x-ray tube is operated
above 50 kVp.
A. size of no more than 3.2 x 4.1 cm
B. size of no more than 3.5 x 4.4 cm
C. diameter of no more than 2¾ inches
D. diameter of no more than 3.2 cm
C
67
The purpose of the aluminum filter is to remove ___ of relatively ___ energy.
A. electrons; higher
B. electrons; lower
C. photons; higher
D. photons; lower
D
68
to protect personnel during exposure of dental radiographs:
A. the operator should stand at least 2 feet from the tube head.
B. it is necessary to line the walls of the area with lead.
C. the operator should stand at an angle of 90 to 135 degrees to the central ray of the x ray beam and at least 6 feet
away from the patient.
D. walls must be of sufficient density or thickness so that the exposure to occupationally exposed individuals is no
greater than 110 Gy per year.
C
69
If correct film placement and retention are not possible because of a patient limitation, the ____ should hold films or sensors in place.
A. patient
B. operator
C. dental assistant
D. parent or other individual responsible for the patient
D
70
The best way to ensure that dental office personnel are not receiving excessive radiation exposure is by: is
use of an aluminum step-wedge to monitor radiographic quality.
B. personnel-monitoring devices.
C. regular training seminars.
D. video monitoring.
B
71
Which of the following statements is true regarding focal spot size and image clarity?
A. A large focal spot will reduce heat dissipation.
B. A small focal spot will improve image clarity.
A large angle of the target will distribute the electron beam over a smaller surface and increase the heat generated
per unit of target area.
D. A small angle of the target will reduce the wearing effect on the target and result in a larger effective focal spot.
B
72
_____ will minimize loss of image clarity and improve the quality of radiographs.
A. Increasing the distance between the object and the receptor (whether film or digital)
B. Increasing the distance between the focal spot and the object
C. Decreasing the distance between the focal spot and the object
D. Increasing the distance between the focal spot and the receptor
B
73
___ the focal spot-to-receptor distance and
___ the object-to receptor distance minimize
image magnification.
A. Increasing; increasing
B. Increasing; decreasing
C. Decreasing; increasing
D. Decreasing; decreasing
B
74
to reduce image shape distortion, the receptor should be parallel with the:
A. central ray and perpendicular to the long axis of the object.
B. long axis of the object and the central ray.
C. long axis of the object and perpendicular to the central ray.
D. vertical axis of the room and perpendicular to the central ray.
C
75
The bisecting-angle technique attempts to bisect the angle created by the:
A. receptor and the PID of the tube head.
B. teeth and the receptor.
C. receptor and the horizontal plane.
D. central ray and the teeth.
B
76
The one facet of using the paralleling technique in positioning and exposing radiographs that is inferior to the
bisecting technique is that:
A. the paralleling technique exposes the patient's thyroid to more radiation than the bisecting technique because of
greater vertical tube head angulation.
B. there is greater magnification of the image using the paralleling technique than the bisecting technique.
C. a greater number of radiographs must be exposed to complete a full-mouth set of radiographs when the paralleling
technique is used.
D. receptors exposed using the paralleling technique will show more foreshortening than receptors exposed using the
bisecting technique.
B
77
For the buccal object rule, if the tube is shifted and directed at the reference object from a more mesial dirxn and
the object in question moves distally w/ respect to the reference object, the object lies ___ to the reference object.
A. lingual
B. buccal
C. mesial
D. distal
B
78
The "B" in the acronym SLOB stands for:
A. behind.
B. basic.
C. buccal.
D. below.
C
79
Which of the following statements is true concerning the composition of x-ray film?
A. The incident beam is recorded on the film to create an image.
B. The emulsion contains silver halide grains, primarily crystals of silver iodide.
C. The silver halide grains in InSight film are flat, tabular crystals.
D. The emulsion is applied to one side of the supporting base, the side that will face the tube head.
C
80
Which of the following statements is true concerning InSight and Ultra-Speed film?
A. The silver halide grains in Ultra-Speed film are flat, tabular crystals.
B. The tabular crystals of InSight film are oriented parallel with the film surface.
C. InSight film is composed of globular-shaped crystals about 1 um in diameter.
D. Ultra-Speed film requires only about half the exposure of InSight film.
B
81
All intraoral dental film is ___ film.
A. screen
B. direct screen
C. direct exposure
D. exposure
C
82
The base for dental x-ray film is made of:
A. collagen.
B. plastic.
C. silver iodide.
D. silver bromide.
B
83
The lead foil backing is positioned behind ___
in the film packet.
A. the outer plastic wrapper and in front of the protective black paper layer
B. the protective black paper layer and in front of the film
C. the protective black paper layer and outside the outer plastic wrapper
D. both the film and the protective black paper layer
D
84
Size ___ dental film is normally used for adult bitewing views.
A. 0
B. 1
C. 2
D. 3
B
85
Fast intensifying screens used for extraoral films have ___ phosphor crystals and efficiently convert x-ray photons to visible light but produce images with ___ resolution than slower screens.
A. large; higher
B. large; lower
C. small; higher
D. small; lower
B
86
The overall degree of darkening of an exposed film is referred to as:
A. radiographic density.
B. radiographic contrast.
C. subject density.
D. subject contrast.
A
87
Changing which of the following variables will result in decreased film density?
A. Increasing the milliamperage (mA)
B. Increasing the peak kilovoltage (kVp)
C Increasing the focal spot-to-film distance
D. Increasing the exposure
time
C
88
Which of the following natural structures has the least density?
A. Bone
B. Dentin
C. Cementum
D. Fat
D
89
The fastest dental film currently available has a(n) ___-speed rating.
A. D
B. E
C.F
D. G
C
90
A high-kVp exposure produces images with
latitude and
contrast.
A. narrow; low
B. narrow; high
C. wide; low
D. wide; high
C
91
___ is caused by a fluctuation in the number of photons per unit of the beam cross-sectional area
absorbed by an intensifying screen.
A. Film latitude
B. Quantum mottle
C. Screen structure mottle
D. Radiographic blurring
B
92
Periapical film can resolve about
the number of line pairs per mm
than film-screen combinations.
A. one-half
B. four times
C. 10 times
D. 20 times
B
93
Diffusion of light from an intensifying screen can be minimized and image sharpness maximized by:
A. ensuring as close contact as possible between the intensifying screen and film.
B. increasing the thickness of the phosphor layer.
C. using intensifying screens with large crystals.
D. exposing an area of film larger than the phosphor crystal.
A
94
The presence of an image on each side of a double-emulsion film means the film will:
A. require twice the exposure time as a single-emulsion film.
B. require a higher kVp to be exposed than a single-emulsion film.
C. have a slight loss of image sharpness because of parallax unsharpness.
D. have decreased density, in contrast to a single-emulsion film.
C
95
Image sharpness is improved by ___
the distance between the focal spot and the object and ___
the distance between the object and the image receptor.
A. increasing; increasing
B. increasing; decreasing
C. decreasing; increasing
D. decreasing; decreasing
B
96
A grid:
A. increases the number of scattered photons in the remnant beam that reach the film.
B. reduces subject contrast.
C. removes scattered photons from a remnant x-ray beam.
D. can be moved parallel with the direction of grid lines during exposure to delete the image of radiolucent grid lines
on the film.
C
97
When the silver halide crystals are irradiated, the charged sensitivity sites attract:
A. negatively charged bromine ions.
B. neutral bromine atoms.
C. positively charged free interstitial silver ions.
D. negatively charged free interstitial silver ions.
C
98
Developer converts silver ___
crystals with neutral silver atoms deposited at the latent image sites into
black, solid silver metallic grains.
A. bromine
B. bromide
C. iodine
D. iodide
B
99
Fixer removes unexposed, undeveloped ___
crystals, leaving the film clear in unexposed areas.
A. silver iodide
B. silver bromide
C. neutral bromine
D. silver ion
B
100
A radiographic image contains dark, or ___
areas that were struck by many ___
A. radiolucent; electrons
B. radiolucent; photons
C. radiopaque; electrons
D. radiopaque; photons
B
101
Which of the following choices is a developing agent used in developing solution?
A. Sodium or potassium hydroxide
B. Phenidone
C. Sodium sulfite
D. Potassium bromide
B
102
It is recommended that ___ of fresh developer be added daily per gallon of developing solution to replenish
the developer.
A. 2 tablespoons
B. 8 tablespoons
C. 2 ounces
D. 8 ounces
D
103
Which of the following film-processing procedures is not used w/ automatic processing, although it is typically
used for manual processing?
A. Immerse exposed film in developer.
B. Rinse film in water bath.
C. Immerse film in fixer.
D. Wash film in water bath.
B
104
Which component of fixing solution is commonly known as "hypo"?
A. Acetic acid
B. Ammonium thiosulfate
C. Ammonium sulfite
D. Aluminum sulfate
B
105
Inadequate washing will result in brown discoloration from the reaction of:
A. acetic acid with air.
B. silver sulfide with aluminum sulfate.
C. thiosulfate with silver.
D. ammonium sulfite with ammonium thiosulfate.
C
106
To minimize the fogging effect of prolonged exposure, the safelight should be mounted at least ___ above the surface where opened films are handled.
A. 6 inches
B. 1 foot
C. 4 feet
D. 8 feet
C
107
Which of the following statements is true concerning use of darkroom safelights?
A. X-ray films are very sensitive to yellow and red wavelengths and less sensitive to the blue-green region of the
spectrum.
B. The ML-2 filter is recommended as a safelight in darkrooms where either intraoral or extraoral films are handled.
C. Film handling under a safelight should be limited to about 5 minutes.
D. Yellow light filters are appropriate for fast intraoral dental film or extraoral panoramic or cephalometric film.
C
108
Fixer is typically placed in the:
A. master tank.
B. cover of the master tank.
C. insert tank on the left side of the master tank.
D. insert tank on the right side of the master tank.
D
109
Rapid-processing solutions often contain a higher [ ] of ___
than conventional processing solution.
A. hydroquinone
B. potassium hydroxide
C. sodium bicarbonate
D. sodium sulfite
A
110
When managing radiographic waste, the primary ingredient of concern in processing solution is the:
A. phenidone.
B. dissolved silver found in used fixer.
C. ammonium thiosulfate "hypo."
D. acetic acid.
B
111
When duplicating radiographs:
A. the film to be duplicated is placed on the opposite side from the emulsion side of the duplicating film.
B. the films are exposed by the x-ray beam.
C. duplicating film gives a negative image of the x-ray film.
D. images on duplicating film that are too dark are underexposed.
D
112
One advantage of digital imaging versus film imaging is that digital:
A. imaging has a lower initial setup expense.
B. imaging eliminates chemical processing.
C. components are inexpensive to replace.
D. systems will not become obsolete over time.
B
113
Production of a digital image requires a process called analog-to-digital conversion, which involves:
complementary metal oxide semiconductors.
B. flat panel detectors.
C. photostimulable phosphors.
D. sampling and quantization.
D
114
Each pixel is isolated from its neighboring pixels and is directly connected to a transistor covalent bonds between silicon atoms are broken, producing electron-hole pairs when the ___ is used as a digital image receptor.
A. charge-coupled device (CCD)
B. complementary metal oxide semiconductor (CMOS)
C. flat panel detector
D. photostimulable phosphor (PSP)
B
115
Cone beam imaging is most likely to use ___
as a receptor.
A. photostimulable phosphors
B. flat panel detectors
C. charge-coupled devices
D. complementary metal oxide semiconductors
B
116
The photostimulable material used for radiographic imaging with the ___
is "europium-doped"
barium fluorohalide.
A. charge-coupled devices
B. flat panel detectors
C. complementary metal oxide semiconductors
D. photostimulable phosphor
D
117
Adequately exposed photostimulable phosphor (PSP) plates may be stored ___
and retain acceptable
image quality.
A. a few minutes
B. 12 to 24 hours
C. a week to 10 days
D. indefinitely
B
118
Regardless of the number of density differences that a detector can capture, conventional computer monitors are
capable of displaying a grayscale of__ bits.
A. 8
B. 10
C. 12
D. 16
A
119
The human visual sys is capable of distinguishing about ___ gray levels at any time under ideal viewing conditions.
A. 8
B. 30
C. 60
D. 256
C
120
Typical observers are able to distinguish about ___ line pair/mm. without benefit of magnification. Current PSP systems are capable of providing more than ___ line pair/mm. of resolution.
A. 6; 7
B. 6; 20
C. 16; 7
D. 16; 20
A
121
Current PSP systems for intraoral imaging allow dose reductions of about % in comparison with F-speed film
with similar diagnostic performance.
A. 10
B. 50
C. 75
D.90
B
122
Which of the following statements is true concerning printing digital radiographs?
A. The resolution of the digital radiograph can always be increased by a printer that prints at a higher resolution than
that of the image itself.
B. Printing digital radiographs at a lower resolution may reduce the final resolution of the image unless the printed
size of the image is decreased.
C. Contrast resolution is always reduced by the printing process.
The printer is capable of printing 256 shades of gray.
C
123
Histogram equalization is an enhancement operation that ___ contrast between those image intensities abundantly present within the image while ___ contrast between image intensities that are used only sparsely.
A. increases; increasing
B. increases; reducing
C. decreases; increasing
D. decreases; reducing
B
124
Which of the following statements is true concerning sharpening and smoothing filters?
A. Filters that smooth an image are sometimes called despeckling filters because they remove low-frequency noise.
B. Filter that sharpen an image either remove high-frequency noise or enhance boundaries between regions with
different intensities.
C. Noise is often categorized as high-frequency noise (gradual intensity changes) or low frequency noise (speckling).
D. There is no scientific evidence suggesting an increase in diagnostic value when sharpening or smoothing filters
are used.
D
125
Which of the following is true concerning color conversion of grayscale images by current digital systems?
A. Most digital systems on the market provide opportunities for color conversion of grayscale images to true-to-life
color.
B. Humans can distinguish many more shades of gray than colors.
C. Transforming the gray values of a digital image into various colors could theoretically enhance the detection of
objects within the image.
D. For digital radiography, all the gray values representing an object are unique for that object.
C
126
If there is a change in the radiographic attenuation between the baseline and follow up examination when digital subtraction radiography is used, this change shows up as a ___ area when the change represents gain and as a ___ area when the change represents loss.
A. darker; brighter
B. brighter; darker
C. red; green
D. green; red
B
127
When digital subtraction radiography is used, if the projection geometry used for the follow-up image 1S different
from the projection geometry used for the baseline image, the subtraction image will show these differences. These
differences can be difficult to distinguish from actual changes within the patient, or they may hide actual changes.
A. Both statements are true.
B. Both statements are false.
C. The first statement is true; the second statement is false.
D. The first statement is false; the second statement is true.
A
128
The goal of ___ during automated image analysis operations is to simplify the image and reduce it
to its basic components.
A. segmentation
B. feature extraction
C. object classification
D. subdividing
A
129
The file size of dental digital radiographs may be as large as ___ for extraoral images.
A. 20 kB
B. 200 kB
C. 6 MB
D. 600 MB
C
130
Which of the following statements is true regarding lossless compression methods for reducing the size of digital
image files for archiving or transmission?
A. Lossless methods discard image data, and lossy compression does not discard data.
B. The maximum compression rate for lossless compression is 12:1 to 14:1.
C. Empiric evidence shows that the higher levels of compression used by lossy compression methods do not
necessarily affect the diagnostic quality of an image.
D. For determining endodontic file length, a compression rate of 25: 1 was diagnostically inferior to the
uncompressed image.
C
131
Whether or not dentists need high-resolution detectors and whether they can use image compression should be
dictated by:
A. the federal government.
B. diagnostic criteria.
C. computer hardware manufacturers.
D. the judicial system.
B
132
Which of the following represents the current systems compatibility standard for digital imaging systems?
A. JPEG
B. TIFF
C. DICOM
D.ACR
C
133
Photostimulable phosphor (PSP) plates are susceptible to bending and scratching during handling:
A. as with charge-coupled device (CCD) sensors.
B. and are much more adaptable then their film counterparts.
C. and this will induce permanent artifacts in the receptor.
D. but they are easily removed during processing procedures.
C
134
The Soredex Optime system has addressed the issue of images from plates that have been exposed backward by
incorporating a:
A. lead foil with a characteristic embossed pattern on the back of intraoral plates.
B. round metal disk on the back of intraoral plates.
C. computerized warning system in the film
processor.
D. slot in the film processor that rejects backward films.
B
135
Digital receptors should be:
A. immersed in disinfecting solution.
B. sterilized by conventional means.
C. disinfected by wiping with mild agents.
D. disposed after a single use.
C
136
If the processing solutions have become depleted, the resultant radiographs are ___ and have ___ contrast.
A. light; increased
B. light; reduced
C. dark; increased
D. dark; reduced
B
137
When degradation of image quality is evident,
should be changed.
A. developer only
B. fixer only
C. both developer and fixer
D. neither developer nor fixer
C
138
Light images may result from:
A. insufficient developing time.
B. excessive developing time.
C. developer that is too warm.
D. light leaks.
A
139
The optimal temperature for heated automatic processors is ___°F.
A. 68
B. 72
C. 82
D. 88
C
140
To check for light leaks in the darkroom:
A. make a stepwedge from lead foil.
B. place a penny on an unwrapped film for the time required to unwrap and mount a full mouth set of films.
C. purchase a sensitometer.
D. manually process a full-mouth set of radiographs without putting a lid on the tanks.
B
141
Dental x-ray film should be stored in:
A. the refrigerator.
B. a cool, dry facility away
from a radiation source.
C. a lead-lined box.
D. the treatment area.
B
142
According to the text, peak kilovoltage is usually set to ___ kVp.
A. 65
B. 70
C. 90
D. 100
B
143
Cracking of leaded aprons and collars is usually caused by:
A. offgassing of polyvinyl components.
B. degradation from exposure to radiation.
C. folding the shields when not in use.
D. expansion and contraction caused by temperature fluctuations.
C
144
When a dental x-ray machine is properly calibrated, the half-value layer (HVL) of the beam should be at least ___
mm aluminum (Al) at 90 kVp.
A. 1.5
B. 2.5
C. 5.0
D. 7.0
b
145
If a 15-mA and 20-impulse exposure a is made, a second, 10-mA and ___-impulse exposure should be made to evaluate to measure the dose and ensure the linearity of the mA control.
A. 10
B. 20
C. 30
D. 40
C
146
Under standard precautions, all human blood and saliva are treated as if known to be infectious for:
A. human immunodeficiency virus and hepatitis A virus.
B. human immunodeficiency virus and hepatitis B virus.
C. herpes simplex virus 1 and 2
D. hepatitis A virus and hepatitis B virus.
B
147
The American Dental Association (ADA) suggests that when dentists use a chemical agent for disinfection or
sterilization, the agent should be a(n) ___ -registered hospital disinfectant of low to intermediate activity.
A. Food and Drug Administration (FDA)
B. Environmental Protection Agency (EPA)
C. Centers for Disease Control and Prevention (CDC)
D. Occupational Safety and Health Administration (OSHA)
B
148
It is recommended to use ___
to prevent contamination of sensors for digital imaging.
A. sterilization
B. plastic barrier sheaths
C. a registered low-level hospital disinfectant
D. ultraviolet (UV) light
B
149
Which of the following intraoral projections should show all of a tooth, including the surrounding bone?
A. periapical projection
B. bitewing projection
C. occlusal projection
D. panoramic projection
A
150
A full-mouth set of radiographs consists of _____ projections.
A. periapical and occlusal
B. bitewing and periapical
C. occlusal and bitewing
D. panoramic and occlusal
B
151
The full length of the root and at least ___ mm of periapical bone must be visible on an
intraoral periapical radiograph.
A. 0.5
B. 2.0
C. 4.0
D. 6.0
B
152
Most clinicians prefer the _ technique for periapical radiography bc it provides less distorted view of the dentition.
A. bisecting
B. paralleling
C. occlusal
D. bitewing
B
153
For mandibular projections, the dental chair should be positioned:
A. upright and low.
B. upright and elevated.
C. back at a 45-degree angle and low.
D. a back at a 45-degree angle and high.
B
154
For maxillary paralleled projections, the superior border of the receptor generally rests at the:
A. greater palatine foramen.
B. incisive foramen.
C. free gingival margin of maxillary posterior teeth.
D. height of the palatal vault in the midline.
D
155
When the bisecting technique is used, the receptor is positioned:
A. at the midline of the palate for a maxillary projection.
B. as close as possible to the lingual surface of the teeth.
C. parallel to the long axis of the tooth.
D. perpendicular to the long axis of the tooth.
B
156
To radiograph the maxillary arch, the patient's head should be positioned upright with the sagittal plane ___ and the occlusal plane ___
A. horizontal; horizontal
B. horizontal; vertical
C. vertical; horizontal
D. vertical; vertical
C
157
When the mandibular teeth are to be radiographed, the head is:
A. positioned with the occlusal plane horizontal.
B. positioned with the occlusal plane vertical.
C. tilted forward slightly.
D. tilted back slightly.
D
158
The film receptor should be placed so that the occlusal or incisal edge of the receptor extends ___ the teeth.
A. 5 mm beyond
B. just beyond
C. to the occlusal or incisal edge of
D. 5 mm short of the occlusal or incisal edge of
B
159
The horizontal angulation of the tube head should be pointed so that the central ray 1S directed:
A. at the cementoenamel junction (CEJ) of the tooth.
B. through the contacts.
C. parallel to the occlusal plane.
D. perpendicular to the midsagittal plane.
B
160
Which of the following types of receptor are particularly valuable for detecting interproximal caries in the early
stages of development before it becomes clinically apparent?
A. occlusal
B. periapical
C. bitewing
D. panoramic
C
161
The contact between the maxillary first and second molars often is angled a few degrees more ___ than between the mandibular first and second molars.
A. superiorly
B. inferiorly
C. anteriorly
D. posteriorly
C
162
The aiming cylinder is positioned about
degrees for a bitewing examination in order to project the beam
parallel with the occlusal plane.
A. +20
B. +10
C. zero
D. -10
B
163
164
The premolar bitewing projection should include the ___ half of the ___
A. distal; canines
B. mesial; canines
C. distal; lateral incisors
D. mesial; lateral incisors
A
165
Which of the following teeth should be used as the guide for placement of the premolar bitewing receptor?
A. Maxillary canine
B. Mandibular canine
C. Maxillary first premolar
D. Mandibular first premolar
B
166
Occlusal receptors may be made of:
A. film, storage phosphor plates, CCD sensors, or CMOS sensors.
B. film, storage phosphor plates, or CCD sensors.
C. film or storage phosphor plates.
D. film only.
C
167
A ___ % reduction in mA used for the usual young adult gives the proper density for patients under 10 years of age.
A. 75
B. 50
C. 25
D. 10
B
168
The primary dentition examination of a child 3 to 6 years old may consist of ___ anterior occlusal receptors, ___ posterior bitewing receptors, and up to ___ posterior periapical receptors, as indicated.
A. zero; two; two
B. two; two; two
C. two; two; four
D. two; four; four
D
169
For a maxillary anterior occlusal projection on a child with primary dentition, a number ___ receptor should be placed in the mouth, and the central ray should be directed at a vertical angulation of ___ degrees through the tip of the nose toward the center of the receptor.
A. 0; +45
B. 2; +45
C. 0; +60
D. 2; +60
D
170
A complete examination of the mixed dentition consists of ___ incisor periapical views, ___ canine periapical views, ___ posterior periapical views, and two or four bitewings.
A. two; two; two
B. two; two; four
C. two; four; four
D. four; four; four
C
171
Stimulating the ___ dorsum of the tongue or the ___ palate usually initiates the gag reflex.
A. anterior; hard
B. posterior; hard
C. anterior; soft
D. posterior; soft
D
172
If panoramic equipment is not available, an examination consisting of ___ intraoral views provides an excellent survey of edentulous patients.
A. 4
B. 7
C. 10
D. 14
D
