問題一覧
1
In order to avoid the primary beam while raking dental images, you should stand at a ___-degree to ____-degree angle to the beam
90; 135
2
One gray is equivalent to _______ rad(s)
100
3
The fundamental unit of matter is the
atom
4
Your X-ray machine runs off 110 volts. Theoretically what would occur if there was no step-down transformer in the X-ray control panel?
too many electrons would be produced for the purpose of dental X-ray. only 3 to 5 volts are required to heat the tungsten filament
5
What specific mechanism of radiation injury may result in the formation of hydrogen peroxide when. X-ray energy is absorbed by patients?
free radiation formation created by the ionization of water may occur
6
Radiation is defines as
a form of energy carried by waves or streams of particles
7
The nucleus of an atom contains
protons and neutrons
8
Which of the following cells would be the most sensitive to X-rays ?
blood
9
The primary dictum of operator protection guidelines is that the operator must
avoid the primary beam
10
Your patient was out in the hot, bright sun yesterday. While in the sun she began experiencing pain and noticed her skin had turned bright red. Shortly after arriving home, she began to experience chills, nausea, severe pain, and blistering. Why would your patient experience the symptoms so quickly?
the latent period was decreased by the increased dose and dose rate
11
Which of the following four possibilities that can occur when an X-ray photon interacts with matter is responsible for producing densities on a dental receptor that make dental radiography possible ?
no interaction
12
A nonthreshold dose-response curve suggests that
radiation exposure, no matter how small, causes damage to living tissue
13
Within the X-ray tube, electrons are generated by the
tungsten filament in the cathode
14
The purpose of the anode is to
covert electrons into X-ray photons
15
Which of the following statements is true of ionization ?
an atom that gains an electron has a negative charge , and atom that loses electron had a positive charge
16
Your patient is receiving radiation treatments for Brest cancer. She reports having a burnin sore throat and great difficulty swallowing. Which stage of the radiation injury sequence is your patient in ?
injury
17
Which of the following type of position-indicating devices (PIDs) produce excess scatter radiation ?
conical
18
Precautions should be taken during dental imaging procedures to which of the following critical organs in the head and neck regions? (1) skin, (2) thyroid gland, (3) lens of the eye, and (4) bone marrow
1,2,3,4
19
Interaction with the X-ray photon as a result of the photoelectric effect is harmful to the patient beacuse ionization occurs
the statement is true
20
You could be exposed to each of these radiation sources in your daily activities. Which of these sources is human-made?
atomic fallout
21
Inherent filtration in the dental X-ray tube head
includes filtration that takes place when the primary beam passes through the glass window of the X-ray tube, the insulating oil, and the tube head seal
22
The lead collimator
restricts the size of the xray beam
23
Risk estimates suggest (1) that death is more likely to occur from common activities than from dental imaging procedures and (2) that cancer is much more likely to be unrelated to dental imaging radiation exposure
both statements are true
24
A 1 in 1 million risk of a fatal outcome is associated with which of the following activities?
all three of the above activities
25
Which form of the X-ray beam is most detrimental to the patient and operator ?
scatter radiation
26
Which would you adjust if you wanted to produce characteristic radiation?
kilovoltage
27
(1) radiation is the emission and propagation of energy through space or a substance in the form of waves or particles. (2) radioactivity can be defined as the process by which certain unstable atoms or elements undergo spontaneous disintegration, in an effort to attain a more balanced nuclear state.
both statements are true
28
A radiograph is defined as
an image or picture produced on a receptor by exposure to ionizing radiation
29
Your patient is concerned about radiation exposure. Which of the following explanations would you give to your patient to help calm her concerns ?
I am using this collimator attachment, which will decrease the X-ray dose you receive by 60% to 70%
30
Which would you adjust if you wanted to create a larger electron cloud ?
milliamperage
31
Stochastic biologic effects from radiation
occur as a result of exposure, but severity is not determined by dose
32
Which of the following can you do after X-ray receptor exposure to reduce(s) the amount of x-radiation your patient receives?
proper instrument technique
33
Which of the following components of the X-ray machine would have two indicator lights?
the control panel
34
The bombing at Nagasaki and Hiroshima took place in 1945; an increase in the incidence of cancer was noted in 1956. Which of effects apply to the cancer incidence ?
long-term, somatic
35
Electromagnetic radiation
includes X-ray and visible light
36
Cathode rays are derived from which of the following types of particulate radiation?
electrons
37
The traditional unit of dose is called
the radiation absorbed dose (rad)
38
Which of the following is a sign or symptom of acute radiation syndrome (ARS)?
hair loss
39
An ion pair results when
an electron is removed from an atom
40
Which of the following would you place in the patient’s mouth in order to take dental X-rays ?
image receptor
41
Heat is a byproduct of X-ray production. Which component of the xray tube head dissipates the heat created by the production of X-rays ?
insulating oil
42
Which of the following statements is true of ionizing radiation?
it is radiation that is capable of producing ions by removing or adding an electron to an atom
43
Your patient asked you why dental images are important. Which of the following is the correct response?
many dental diseases are typically discovered only through the use of dental images
44
Which of the following statements is true of orbits or shells in the atom ?
the orbiting shell closest to the nucleus has the highest energy level
45
Who exposed the first dental radiograph in the US using a live person ?
Edmund Kells
46
A circular collimator produces a cone-shaped beam that is ________ inch(es) in diameter
2.75
47
The spontaneous emmision of radiation from the disintegration of unstable atomic nuclei is
radioactivity
48
Which of the following statements is true of characteristic radiation?
it only occurs at 70kv and above
49
Your patient had X-rays taken in her previous dental office. She noticed that the long metal tube at the end of the X-ray head is longer than it was at the other office. What explanation would you give for the purpose of the tube, attached to the X-ray head?
it aims and shapes the X-ray beam
50
Which of the following statements is true of the average dose of background radiation received by an individual in the United States ?
geographic areas at higher elevations are associated with increased amounts of cosmic radiation
51
Current fast radiograph film requires ___% less exposure time than the initial exposure times used in 1920
98
52
_________ is/are the single largest contributor to artificial radiation exposure (0.00053 Sv/year)
medical radiation
53
Who modified the paralleling technique with the introduction of the long-cone technique?
F. Gordon Fitzgerald
54
Which types of cells are more sensitive to radiation : (1) rapidly dividing,(2) slowly dividing, (3) young, and/or (4) old?
1 and 3
55
The indirect theory proposes that
toxins are created from the formation of free radiation
56
A film badge
is worn at waist level by the operator
57
Which of the following statements is true regarding the direct theory of radiation injury?
it involves damage to the critical areas of a cell through direct contact with the X-ray photon
58
Added filtration in the dental X-ray tube head
results in a more penetrating useful beam
59
The use of F-speed film instead of D-speed film reduces the absorbed dose by ___%
60
60
Which of the following combinations will result in the lowest absorbed dose for the patient from a 29-film series of dental radiographs ?
rectangular collimation with digital sensor
61
Which of the following is an advantage of digital imaging ?
increased speed for viewing images
62
Which of the following forms of electromagnetic radiation has the shortest wavelength?
dental X-ray wave
63
The “Guidelines for Prescribing Dental Radiographs” state that
dentulous adult recall patients who are not at increased risk for caries should have posterior bite-wing examinations at 24- to 36-month intervals
64
Which discovery was the precursor to the discovery of X-rays ?
cathode rays
65
Photons are
a component of the particle concept of electromagnetic radiation
66
A rectangular collimator
decreased patient exposure considerably
67
(1) X-ray photon production occurs as a result of both general and characteristic radiation. (2) general radiation accounts for a small number of X-ray photons produced beacuse it takes high kv to dislodge the electrons from the K shells
the first statement is true ; the second statement is false
68
(1) all ionizing radiations cause damage to living tissues (2) although very little radiations is used in dentistry, damage to the cells does occurs
both statements are true
69
The X-ray was discovered by
Wilhelm Roentgen
70
Your patient is concerned about being exposed to dental X-rays. Which of the following could you tell your patient to alleviate her fears ?
the risks from dental imaging are not significantly greater than the risks of other everyday activities in modern life
71
Which of the following should you do prior to taking X-rays to protect your patient from radiation exposure?
proper prescribing of radiographs
72
Which of the following statements is true of somatic effects of irradiation?
changes are not transmitted to future generations
73
The SI equivalent of the rem is
the sievert
74
Which of the following is the least sensitive to X-rays ?
salivary glands
75
Which of the following elements is the simplest atom?
Hydrogen (H#1)
76
Which of the following is associated with long-term radiation effects?
small amounts of radiation absorbed over a long period
77
Which property of X-rays allows for the image on the receptor?
penetrating power
78
Which type of PID would be most effective in reducing patient exposure?
a 16-inch rectangular PID
79
Which is the most common possibility when an X-ray photon interacts with matter?
Compton scatter
80
____ refers to the total amount of radiation that is received or absorbed
total dose
81
Cellular injuries following the latent period may include (1) cell death, (2) cessation of mitotic activity, and/or (3) abnormal mitotic activity
1,2,3
82
In the dental X-ray tube, the number of electrons created is controlled by
milliamperage
83
(1) more radiation damage takes place with high dose rates (2) because a rapid delivery of radiation does not allow time for cellular damage to be repaired
both statements are true
84
The binding energy it binding force of an electrons is
determined by the distance between the orbiting electrons and the nucleus
85
Explain to your patient the steps, in order, in the formation of hydrogen peroxide, a toxin that will cause damage to living tissues. 1. Free radicals combine 2. Free radicals formation 3. Cellular dysfunction and biologic damage 4. X-ray photons are absorbed by water
4,2,1,3
86
Thermionic emission electrons occurs at the
tungsten filament in the cathode
87
Which subatomic particles carries a negative electrical charge ?
an electron
88
Radiation monitoring can be used to protect the dental radiographer and includes monitoring of
both equipment and personnel
89
The potential risk of dental radiography inducing a fatal cancer in an individual is about _____ the risk of a person developing cancer spontaneously
1/1000
90
According to the dose-response curve, when dose and damages are plotted on a graph, a _____________ relationship is seen
linear, nonthreshold
91
State and federal laws require that dena X-ray machines operating above 70kVp have a minimum total ( inherent plus added filtration) of ____ mm of aluminum filtration
2.5
92
The thyroid collar
is recommended for all intraoral exposures
93
Which of the following is an example of stochastic effects?
hair loss
94
Approximately what percentage of the kinetic energy of the electrons is converted to X-rays at the anode ?
less than 1%
95
The lead apron
Is recommended for intraoral exposures
96
__-speeed film is currently the fastest intraoral film available
F
97
The collimator __________
restricts the size and shape of the X-rays beam
98
On some dental X-ray machines, only the ______ can be altered; the other parameters are preset by the manufacturer
exposure time
99
Uranium is example of ________ radiation
terrestrial
100
Which of the following statements is true of the wave concept of electromagnetic radiation?
frequency and wavelength are inversely related