Radiology I- Radiologic Physics, Radiation Protection & Biology Flashcards
1
Q
According to the law of Bergonie and Tribondeau, living tissues with high radio sensitivity include:
A
- cells with high metabolic activity
- tissues with high growth rate
2
Q
T/F the most critical time for irradiation of a fetus is during the first two weeks of gestation
A
TRUE
3
Q
T/F in a linear, non-threshold dose-response relationship, any dose, regarding of its size, is expected to produce a response.
A
TRUE
4
Q
T/F The radiolysis of water results in the formation of free radicals but not ions.
A
FALSE
5
Q
T/F It is not necessary to return the control film badge at the end of each month when returning the personnel film badges to the radiation dosimetry company.
A
FALSE
6
Q
Protective barrier thickness is determined by the:
A
- distance between the radiation source and the barrier
- number of examinations performed per week (workload)
- penetrability of the x-ray beam
- time of occupancy of the area
7
Q
a free radical
A
is highly active
8
Q
T/F primary protective barriers are mainly used to shield areas from scatter and leakage radiation
A
FALSE
9
Q
When water is irradiated, it dissociates into other molecular products. this action is known as:
A
radiolysis
10
Q
an example of primary radiation is
A
the useful beam
11
Q
T/F human cells aren’t capable of recovering from radiation damage.
A
FALSE
12
Q
ways to reduce unnecessary pt dose include:
A
- eliminate repeat exams
- position glands out of the primary beam
13
Q
T/F compared to using an appropriate kVp technique and appropriate film-screen combination, lowering kVp and selecting a slower speed film-screen combination will increase the pt’s dose.
A
TRUE
14
Q
T/F as the proliferation rate for cells and the growth rate for tissues decrease, the radio sensitivity decreases also.
A
TRUE
15
Q
T/F lead aprons and gloves should be folded and placed flat on a shelf.
A
FALSE
16
Q
the unit of dose equivalent or occupational exposure that is used to express the quantity of radiation received by a radiation worker is known as the:
A
rem
17
Q
the most radiosensitive macromolecule is
A
DNA
18
Q
precautions to take before or during radiography on a pregnant pt include:
A
- document
- collimate
- shield
- high kVp technique
19
Q
cardinal principles of radiation protection include:
A
- minimize time
- maximize distance
- maximize shielding
20
Q
fetal congenital abnormalities will most likely occur if the fetus is irradiated during the:
A
3-8 wks
21
Q
T/F radiation-induced malignancy and genetic effects are late effects of low-dose radiation over long periods of time
A
TRUE
22
Q
T/F secondary barriers are used to shield against the useful beam
A
FALSE
23
Q
scatter radiation is increased by:
A
- increasing the field size
- thicker body parts
24
Q
a material used as a primary barrier is
A
concrete
25
reduction of unnecessary pt dose can be achieved by:
collimating the area in question
26
a cardinal principal of radiation protection is to minimize:
time
27
a measure of the rate at which energy is transferred from ionizing radiation to soft tissue is known as:
linear energy transfer
28
an early effect of radiation on humans is:
skin erythema
29
of the following, the cell type that has the highest radio sensitivity is the:
lymphocyte
30
T/F a free radical is a charged molecule containing a single unpaired electron in the valence or outermost shell
FALSE
31
T/F a film badge (or, personnel monitor) is properly worn at chest level
TRUE
32
T/F The 3 principal observable effects resulting from irradiation of DNA include cell death, malignant disease, and genetic damage.
TRUE
33
T/F free radicals cause damage by the direct effect of radiation.
FALSE
34
the principle observable effects resulting from irradiation of DNA include:
- cell death
- malignant disease
- genetic damage
35
T/F the delayed or late effects of radiation can follow low doses delivered over a long time period.
TRUE
36
T/F biologic tissue is more sensitive to radiation when irradiated in the oxygenated (aerobic) state.
TRUE
37
T/F a measure of the rate at which energy is transferred from ionizing radiation to soft tissue is known as linear energy transfer
TRUE
38
T/F a podiatric assistant should be used to hold an infant during an x-ray procedure, not the parent
FALSE
39
T/F when the level of metabolic activity is low, radio sensitivity is high
FALSE
40
T/F research has shown, on avg, that a full-time radiographer's life-span is shortened by 4 years.
FALSE
41
the following dose-response relationship has been adopted as the model for establishing radiation protection guidance:
linear non-threshold
42
T/F major effects of macromolecule irradiation include main-chain scission, cross-linking, and point lesions.
TRUE
43
the unit of radiation measurement that is used to describe the radiation quantity or dose absorbed by the pt is known as the:
rad (gray)
44
T/F a free radical can join with a similar molecule and form hydrogen peroxide which is poisonous to the cell
TRUE
45
If an undetected pregnant pt is irradiated, the:
fetal dose should be estimated
46
T/F lead-lined barriers are required for secondary protective barriers.
FALSE
47
the least radiosensitive macromolecule of the following is:
protein
48
T/F the dose-response relationship for radiation-induced cataracts is apparently threshold, non-linear
FALSE
49
a cell type that exhibits high radio sensitivity to ionizing radiation is:
lymphocyte
50
of the following, the organ or tissue that has the highest radio sensitivity is:
gonad
51
T/F the principle action of radiation on humans is by the direct effect.
FASLE
52
T/F ALARA stands for as large as reasonable achievable.
FALSE
53
T/F a pregnant radiographer should wear an additional personal monitoring device under her apron at waist level.
TRUE
54
if an infant needs to be held still during a radiographic study, it should be done by the
guardian or parent
55
barriers are used to shield against:
- the useful beam
- leakage radiation
- scatter radiation
56
T/F MPD (max permissible dose) is defined as the max dose of radiation expected to produced significant radiation effects.
FALSE
57
T/F the age of a biologic structure affects its radiosensitivity
TRUE
58
The pregnant radiographer should:
have her previous radiation exposure history reviewed
59
T/F the late effect of radiation is defined as follows: the radiation response occurs within minutes or days after radiation exposure.
FALSE
60
T/F the law of Bergonie and Tribondeau states the following: tissues that are younger, have a high level of metabolic activity, and have a high growth rate are more radiosensitive.
TRUE
61
according to the Law of Bergonie and Tribondeau:
radio sensitivity increases with increasing tissue growth rate
62
the effects of proper collimation are:
- reduce pt dose
| - improve image contrast
63
T/F the damage caused by free radicals as they transfer their energy to a target molecule occurs by the direct effect of radiation.
FALSE
64
T/F if the initial ionizing event occurs on the molecule that is irradiated, the effect is said to be indirect
FALSE
65
regarding radiation-protection design for x-ray equipment:
the output radiation intensity should be constant from one exposure to the next
66
T/F one factor that barrier thickness depends on is the distance bw the radiation source and the barrier
TRUE
67
T/F an infant should be held still during the exposure b the radiographer, not the parent or guardian.
FALSE
68
T/F a cardinal principle of radiation protection is to maintain a large distance bw the body part and the film
TRUE
69
T/F a cardinal principle of radiation protection is to keep the time of radiation exposure long
FALSE
70
T/F radiation dose-response relationships are used to design therapeutic treatment routines for pts with cancer and to provide info on the effects of low-dose irradiation.
TRUE
71
T/F the linear, non-threshold dose-response relationship states that a specific irradiation dose is necessary to produced a response in tissue .
FALSE
72
the biologic effectiveness of radiation energy absorbed is measured by the:
rem
73
protective barrier thickness is determined by the:
all of the above answers are correct
74
T/F generally speaking, the older tissues and organs are, the less radiosensitive they are:
TRUE
75
T/F fetal exposure of radiation drink the first week of pregnancy will most likely result in skeletal deformities.
FALSE
76
an uncharged molecule containing a single unpaired electron in the outermost shell is known as a(n):
free radical
77
according to the law of Bergonie and Tribondeau, living tissues with high radiosenstivity include:
- cells with high metabolic activity
| - tissues with high growth rate
78
T/F the film badge control monitor should be kept in the radiography procedure room
FALSE
79
T/F free radicals are formed by the radiolysis of water
TRUE
80
most states recommend that the film badge be worn at the level of the:
collar
81
consider the following 2 characteristics: 1) any radiation dose, regardless of its size, is expected to produce a response; and 2) the response to radiation is directly proportional to the dose. This is known as the:
linear non threshold relationship
82
a disadvantage of the film badge is its:
sensitivity
83
T/F film badges are inexpensive and reasonably accurate. However, they are sensitive to heat and humidity.
TRUE
84
T/F the required thickness of a lead apron is 0.25 mm
TRUE
85
T/F free radicals contain excess energy that can be transferred to other molecules to disrupt bones and produce pt lesions at some distance from the initial ionizing event
TRUE
86
T/F the linear, non threshold relationship can be described as follows: only high radiation doses will be expected to produce a response in human tissues.
FALSE
87
T/F according to the law of Bergonie and Tribondeau, radio sensitivity is a function of the metabolic tissue being irradiated
TRUE
88
T/F The disadvantage of a protective lead apron with higher lead equivalent thickness is that it attenuates more x-rays
FALSE
89
T/F stem cells are radiosensitive
TRUE
90
T/F epidemiological studies of ppl exposed to radiation are easily obtained because the does are known and the frequency response is high
FALSE
91
T/F x-rays and gamma rays are examples of particulate radiation
FALSE
92
the x-ray tube housing:
- reduces leakage radiation
- protects against accidental electrical shock
- contains oil that serves as a thermal cushion
93
T/F a 70 keV x-ray photon has higher energy than a 50 keV photon
TRUE
94
T/F the term "quantity" refers to the penetrating ability of the x-ray beam
FALSE
95
T/F classical scattering is of little importance to diagnostic radiology because it primarily involves low-energy x-rays which contribute little to the raidograph
TRUE
96
the cathode
- is composed of the filament
| - is composed of the focusing cup
97
T/F the production of x-rays that results from the braking of projectile electrons by the target nucleus is known as characteristic radiation
FALSE
98
the exposure factors for a radiographic study of the ankle are 15 mA and 0.5 seconds. in order to obtain the same film density at 10 mA, the new time setting would be (assume that all other factors remain unchanged):
0.75 seconds
99
T/F classical scatter occurs when the x-ray photon changes direction, loses energy, and ionizes an atom
FALSE
100
line A is an initial x-ray emission spectrum. By decreasing ______, line B will result.
kVp
101
T/F generally speaking, approximately 99% of the kinetic energy of projectile electrons traveling between the cathode and anode is converted into x-rays
FALSE
102
an x-ray photon is totally absorbed and an inner shell electron is ejected during ionization. this describes:
photoelectric effect
103
T/F the half-value layer of an x-ray beam refers to the thickness of absorbing material necessary to reduce the x-ray intensity to half of its original value.
TRUE
104
T/F the inverse square law states that the intensity of the x-ray beam is directly proportional to the square of the distance between the object and the source
FALSE
105
the 2 mechanisms of x-ray production are:
- bremsstrahlung
| - characteristic
106
T/F Photoelectric and Compton are ways that x-rays interact with matter, not how they are produced
TRUE
107
the photoelectric effect:
- more likely occurs with inner shell electrons
| - plays an important role in image formation
108
T/F a purpose of the x-ray tube housing is to absorb off focus radiation
TRUE
109
T/F a compensation filter is permanently installed inside the tube head.
FALSE
110
T/F differential absorption of x-rays is dependent upon atomic number and mass density
TRUE
111
the half-value layer is defined as the thickness of absorbing material necessary to reduce the x-ray intensity to ______ its original value.
one-half
112
T/F photons that have long wavelengths have high energy
FALSE
113
T/F differential absorption of x-rays depends on atomic number and mass density
TRUE
114
Variable that can be manipulated on the control panel include:
- kVp
- mA
- time
115
According to the quantum theory, photon energy is:
directly proportional to photon frequency & inversely proportional to photon wavelength.
116
T/F photons interact with matter most easily when matter is approximately the same size as the photon wavelength
TRUE
117
T/F if the kVp setting of an x-ray unit is set at 60, then only x-rays having 60 keV energy are being emitted from the x-ray tube
FALSE
118
T/F increasing the kVp causes the x-ray emission spectrum to shift to the higher energy side
TRUE
119
Examples of ionizing electromagnetic radiation include:
- x-rays
| - gamma rays
120
T/F aluminum added filtration results in an x-ray beam that has an increased effective energy
TRUE
121
T/F rad/gray is the unit of ionizing radiation used to express the quantity of radiation received by radiation workers
FALSE. correct answer is rem/sievert
122
T/F at the anode, only a small amount of the KE of projectile electrons is converted into heat.
FALSE
123
the 2 forms of x-ray interactions with matter most applicable to diagnostic radiology are:
- photoelectric absorption
| - Compton scatter
124
T/F generally, more than 99% of the KE of projectile electrons is converted to heat, which leaves less than 1% available for the production of x-rays.
TRUE
125
T/F the sheet of aluminum located between the tube housing and collimator is known as inherent filtration
FALSE
126
an x-ray:
- travels at the speed of light
- has frequency and wavelength that are inversely related
- has no mass and no charge
127
the type of x-ray interaction with matter that is important for image formation by producing high contrast but leads to a high absorbed patient dose is known as
photoelectric absorption
128
T/F the primary purpose of the oil surrounding the x-ray tube is to cushion the tube so it doesn't break during positioning of the tube head.
FALSE
129
The x-ray interactions with matter that are applicable to diagnostic radiology are:
- Compton scattering
| - photoelectric effect
130
T/F Bremsstrahlung radiation refers to formation of x-rays, not interaction with matter, which Compton scatter and photoelectric effect both refer to
TRUE
131
The following type of x-ray does NOT contribute positively to image formation
Compton scattering
132
T/F during x-ray production, an intense ant of heat is generated at the cathode.
FALSE
133
energy emitted and trasnferred through matter is known as:
radiation
134
T/F x-rays undergo radioactive decay
FALSE
135
T/F the Compton-scattered x-ray contributes no useful information to the radiograph
TRUE
136
T/F a photon is the smallest quantity of electromagnetic radiation
TRUE
137
in the x-ray tube, x-rays are produced at the
anode
138
the Compton-scattered x-ray contributes no useful information to the radiograph
TRUE
139
The anode includes the
target
140
T/F regarding the "heel effect," radiation intensity on the anode side of the x-ray field is lower than that on the cathode side
TRUE
141
T/F attenuation is defined as total absorption of energy
FALSE
142
from the following choices, the form of electromagnetic radiation that has the shorted wavelength is
x-rays
143
the sheet of aluminum found between the protective tube housing and the collimator is known as
added filtration
144
T/F added filtration has no effect on the x-ray emission spectrum
FALSE
145
T/F x-ray photons have no mass, no charge, and travel at the speed of light
TRUE
146
the negative en dog the x-ray tube is the:
cathode
147
T/F characteristic x-rays can be produced if the projectile electron interacts with an inner shell electron of the target atom rather than with the outer shell electron
TRUE
148
_____ are emitted from the nucleus of a radioisotope
gamma rays
149
the following type of filtration is placed along the outer surface of the collimator:
compensation
150
an increase in ___ will NOT cause the x-ray emission spectrum to shift to the right
mA
151
T/F regarding the heel effect, the radiation intensity on the cathode side of the x-ray field is higher than that on the anode side
TRUE
152
factors that can be manipulated on a lower extremity-specific radiography unit include:
kVp, mA, time
153
T/F anatomic structures with high x-ray absorption characteristics are referred to as radiolucent
FALSE
154
ionizing radiation has:
high energy, short wavelength
155
the wavelength of the x-ray photon is controlled by the
kilovoltage
156
T/F more than 99% of the KE of projectile electrons is converted into thermal radiation
TRUE
157
if the source to obj distance is decreased from 30 in to 15 in, then the radiation intensity which originally was 8 would now be
32
| I1/I2=[d2/d1]^2
158
any wall to which the useful x-ray beam can be directed is designated a(n):
primary barrier
159
the purpose of the x-ray tube housing is:
to absorb off-focus radiation
160
_____are produced outside the nucleus in the electron cloud
x-rays
161
factors that affect the x-ray image's optical density include:
mA and kVp
162
you are presently using an exposure technique of 10 mA and 1/2 second with a particular x-ray imaging system. you decide to increase the mA in order to reduce the effect of patient movement on the final image. assuming all other factors remain unchanged, determine the new exposure time using 15 mA
1/3 second
163
T/F high energy x-rays have longer wavelength than low energy x-rays.
FALSE
164
characteristic of x-rays include
ionizing
165
Bremsstrahlung radiation results:
when a projectile electron slows and changes course as it passes the target atom's nucleus
166
T/F characteristic x-rays can be produced if the projectile electron interacts with an outer shell electron of the target atom rather than with the inner shell electron
FALSE
167
T/F a 15% increase in mA is equivalent to doubling the kVp
TRUE
168
At lower energies of x-radiation:
- pt dose increases
| - photoelectric interactions increase
169
Bremsstrahlung radiation occurs when:
a projectiel electron is slowed down
170
T/F x-rays are produced at the cathode side of the tube
FALSE
171
T/F approximately 99% of the KE of projectile electrons in the x-rya tube is converted to x-radiation
FALSE
172
T/F the x-ray tube current, the number of electrons crossing the cathode to anode, is measured in kilovorlts
FALSE
173
the intensity of the x-ray beam is 4 mAs at a distance of 20 inches from the source. What is the intensity of the same x-ray beam at a distance of 40 inches from the source?
1 mAs
174
T/F Generally speaking, if the distance doubles, the intensity will be cut to 1/4
TRUE
175
T/F if all other factors remain unchanged, increasing the source to image distance will decrease the intensity of the x-ray beam at the subject
TRUE
176
the Compton effect:
- changes the x-ray photon direction
- ionizes the target atom
- reduces photon energy
177
T/F added filtration absorbs the high energy x-rays that would otherwise be absorbed by the patient
FALSE
178
T/F differential absorption of x-rays increases as the kVp is lowered
TRUE
179
T/F Compton scatter occurs when the incident x-ray photon is totally absorbed, the atom is ionized, and secondary x-rays are produced
FALSE
180
Differential attenuation (absorption) of the x-ray is dependent on the subject:
- density
- thickness
- atomic number
181
T/F the interaction bw low energy x-rays and atoms that results in the scattering of the original, incident x-ray such that is doesn't lose energy or change wavelength is known as the Compton effect
FALSE
182
sources of natural radiation include:
cosmic rays and radon
183
T/F the radioactive half-life of an x-ray is approximately 2 sec
FALSE
184
the x-ray tube target is made of
Tungsten
185
the heel effect
results in smaller effective focal spot and less radiation intensity on anode side of x-ray beam
186
T/F attenuation is defined as the total reduction in the number of x-ray s remaining in an x-ray beam following penetration through a given thickness of matter
TRUE
187
portions of the electromagnetic spectrum important to diagnostic imagine include:
- x-ryas
- visible light
- radio waves
188
the primary factor that influences x-rays quantity is:
mAs
189
T/F the primary purpose of a collimator is to reduce the pt dose by restricting the volume of the tissue irradiated
TRUE
190
the x-rays that provide the most diagnostic info to the image receptor because they are differentially absorbed are produced by the:
photoelectric effect
191
factors that can influence x-ray quantity include:
- kVp
- mAs
- added filtration
192
the following is/are NOT a source of natural ionizing radiation:
x-rays
193
the smallest quantity of any type of electromagnetic radiation is the:
photon
194
the standard SID for your wall-mounted lower extremity x-ray unit with flexible arm is 28 inches. however, this unit is not easily positioned, and the assistant inadvertently positions the SID at 32 inches. if all other technical factors (mA, time, kVp) remain unchanged, the resultant radiograph will have an optical density that is:
less black
195
according to the inverse square law, if the radiation intensity at a 40 inch SID is 2 Roentgen (R), then the radiation intensity at a 20 inch SID will be:
8R
196
a filter that is placed along the outside of the collimator and is used to adjust for differences in film density due to varying tissue thicknesses is known as:
a compensating filter
197
the amplitude of the x-ray emission spectrum is affected by changes in:
- mA
- kVp
- added filtration
198
the x-ray interaction with matter that results in ionization of the target atom and scatters the photon is known as:
the Compton effect
199
electromagnetic radiation with the shortest wavelength
x-rays
200
factors that affect x-ray quality include:
filtration & kV
201
T/F mAs only affects the quantity or number of x-ray photons; filtration and kV additionally influence the energy of the beam, i.e. its penetrability (or quality)
TRUE
202
T/F the heel effect causes radiation intensity on the anode side of the x-ray beam to be higher than on the cathode side
FALSE
203
T/F the half-value layer of an z-ray beam refers to the thickness of absorbing material necessary to decrease the x-ray intensity to half its original value
TRUE
204
T/F Bremsstrahlung x-rays are produced when a projectile electron interacts with an inner shell electron and removes it
FALSE
205
T/F x-rays have a longer a longer wavelength than visible light
FALSE
206
T/F ionization is the process whereby a proton is removed from a target atom
FALSE
207
T/F Bremsstrahlung radiation is produced following the ionization of an electron
FALSE
208
T/F Bremsstrahlung x-rays demonstrate a discrete x-ray emission spectrum, that is, x-rays with precisely fixed energies
FALSE
209
factors that can affect x-ray quantity include:
- mAs
- kV
- filtration
210
the types of x-rays that are important in making the radiograph include:
- those transmitted through the pt without interaction
- those scattered by Compton interaction
- those absorbed photoelectrically
211
x-rays demonstrate all of the properties of light waves except:
reflection
212
primary factors that affect x-ray quality include:
kvp and filtration
