問題一覧
1
when exposing radiographs , what is the minimum distance the operator should stand from the tube head ?
6 ft
2
which of the following is the most effective method of reducing patient exposure to xradiation?
fast film
3
before exposing radiographs on a minor, the dental assistant should ?
obtain consent from parent or legal guardian
4
the best way to correct a conecutting error is to adjust?
film position
5
ALARA is primarily concerned with the radiation that is ?
artificial
6
to prevent cross contamination, wipe the counter top with ?
an epa approved disinfectant
7
which of the following should be labeled on the radiographic mount prior to the film duplication ?
right and left sides
8
which of the following radiograph techniques is recommended for a patient with a shallow palate?
bisecting
9
compared to radiopaque structures, radiolucent structures?
appear darker on a radiograph
10
the maximum MPD of ionizing radiation for occupational exposure is ?
5.0 rem per year
11
Unique properties of x-rays include their ability to do all of the following except ?
fluoresce all materials
12
an x ray beam contains photons of various energies that relate to which aspect of the beam ?
penetrating power
13
bremsstrahlung is produced when electrons collide with the nuclei of the target atoms, creating ?
x-rays of various lengths
14
the ability of x-rays to remove electrons from a substance is called ?
ionization
15
the extension from the tube head of the xray unit that directs the useful beam is referred to as the ?
PID
16
the shortest waves of the electromagnetic spectrum are measured in?
aangstrom units
17
atoms of cellular structure that have lost electrons are referred to as ?
ions
18
the PID that is least effective in minimizing scatter radiation is the ?
pointed cone
19
which of the following is true of filters found in an xray tube head
they remove x-rays that add to patients abs dose
20
the tungsten filament in the dental xray tube is actually the ?
cathode
21
from what portion of the negative pole of the xray tube are electrons emitted ?
tungsten filament
22
the function of the collimator in the head of the xray unit is to ?
limit the size of the xray beam
23
all of the following are forms of energy except one. which one is the exception ?
water
24
the quality or penetrating ability of the electrons is controlled by the setting of the ?
kilovoltage meter
25
the beam of x-rays that leaves the target is composed of what type of rays?
long wavelengths
26
how many electrical circuits are used in a dental xray machine ?
two
27
which of the following is responsible for all collimation?
lead diaphragm
28
according to federal regulations, the beam size should not exceed what number of inches at the patients skin surface ?
2 3/4
29
patients should wear a thyroid collar during which type of radiographic exposure ?
intraoral radiograph
30
which of the following would cause elongation on a radiograph ?
insufficient vertical angulation
31
an unexposed film will appear ?
light
32
during patient exposure , protection from radiation for the dental assistant includes?
standing behind a drywall barrier
33
who is responsible for designating a chemical as hazardous?
epa
34
radiation injury can be measured by?
dose rate
35
which of the following describes how most radiographic various lesions appear ?
radiolucent
36
insurance carriers can request?
preoperative radiographs
37
a cephalometric radiograph is primarily used to evaluate?
lateral jaw development
38
which of the following should be used to prevent cross contamination from exposure buttons ?
plastic cover
39
to produce ionizing radiation, an atom must ?
add an electron
40
which of the following conditions will result in a radiographic image that is too light ?
weak developing solution
41
which government agency regulates the effectiveness of sterilizers ?
fda
42
the speed of a wave is its
velocity
43
which of these statements is false ?
structures should be magnified to enhance interpretation
44
which of the following is not a type of digital image receptor?
scanner
45
which of these statements is false ?
rampant caries refers to decay that occurs under a restoration or around margins
46
waste materials that present a threat to community health or the environment are called ?
hazardous
47
which of the following occurs at 70kvp or higher and accounts for a very small part of the xrays produced in the dental xray machine ?
characteristics radiation
48
which of the following delineates where the thermionic emission effect takes place ?
tungsten filament at the cathode
49
the person accredited with the initial discovery of xrays is ?
wilhelm conrad roentgen
50
you turn on the dental xray machines for your first patient and in doing so you ?
activate the filament circuit
51
which of the following electrons has the greatest binding energy ?
k shell electrons
52
all of the following are examples of electromagnetic radiation except ?
beta rays
53
which of the following is incorrect?
xrays travel at the speed of sound
54
the dental xray tube is said to be inefficient because?
1% of the energy produced is xradiation
55
which of the following has the ability to affect living organisms?
supervoltage xrays
56
the radiation produced at the atomic level in dents radiography is predominately as a result of ?
bremsstrahlung
57
filters are used in the xray beam to ?
reduce patient radiation dose
58
the best way to describe the penetration of an xray beam is by it ?
half value layer
59
the milliampere control dial on the dental xray machine
regulated the quantity of the radiation
60
in taking the radiograph, you did not center the beam on the film in the patients mouth. the resulting film will show
collimator cutoff ( cone cutting )
61
the dental xray machine in your office operated at 90kvp and this is required to have a total filtration of ?
2.5 mm of aluminum
62
the xray beam from a conventional dental machine is ?
a pulsating divergent beam
63
for a xray timers calibrated in impulses, how many impulses are there in a second ?
60
64
the high voltage circuit in the dental xray machine requires voltage in the range of 65,000 to 100,000 which is the achieved by the use of the ?
step up transformer
65
which of the following materials is most resistant to xradiation?
lead
66
a 16 inch cylinder is used in the paralleling technique to ?
avoid magnification of the image
67
as the distance between the end of the pid and the film increases the ?
intensity of the xray beam decreases
68
image sharpness on a radiograph is increased by?
using a small focal spot size
69
the most likely cause of film with very poor definition is ?
patient movement
70
a radiograph that has many dark and light areas but few gray areas is said to have ?
high contrast
71
to increase contrast , the operator should decrease ?
kilovolt peak
72
use of a kilovolt peak between 45 and 65 produces?
scatter radiation
73
the difference in degrees of blacknesss on a radiograph is called ?
contrast
74
radiographs should always be viewed ?
on a viewbox
75
if the pid is 2 inches away from the patient skin instead of almost touching , the resulting radiograph will be ?
underexposed
76
the criteria for an acceptable radiograph include ?
all of the above
77
the best way to clean the intensifying screens in ectraoral cassette is with ?
soapy water
78
film fog occurs when all part of a radiograph is darkened by?
all of the above are potential sources
79
which of the following statements is false concerning film duplication ?
if less film density is needed on the duplicate radiograph, the exposure time is shortened
80
flexible cassettes are ?
are used in some panoramic units
81
intraoral film packets must be ?
all of the above
82
to what does the term film speed refer ?
sensitivity to xradiation
83
the advantage of a film that has emulsion on both sides is that ?
the film requires less radiation exposure
84
which of the following film sizes is considered to be standard adult film ?
size 2
85
no screen film is routinely used in extraoral radiography ?
false
86
if the intensifying screens are not in perfect contact with the film , which of the following will occur ?
there will be a loss of image sharpness
87
what is the major advantage in using the fastest speed film and high kilovolt peak ?
it reduces the radiation exposure to the patient
88
in taking dental radiographs the greatest dose of radiation to structures in the patients jaw comes from ?
the primary beam
89
ionization has occurred when ?
an electron is displaced from its orbit
90
which form of radiation can cause ionization of atoms ?
gamma rays
91
the ALARA principle refers?
obtaining diagnostically acceptable radiographs with minimal exposure to radiation
92
which of the following travel at the greatest speed?
they all travel at the same speed
93
x-rays that are most likely to be absorbed by the skin are ?
those with long wavelength
94
which of the following types of scatter radiation occurs most often with dental xrays ?
compton
95
an angstrom unit is used to measure?
xray wavelengths
96
the unit that describes the amount of xray exposure in air is the ?
roengten
97
which of the following characteristics of body tissue determines its sensitivity to radiation?
mitotic rate