Final test cont 8-11 Flashcards
(100 cards)
1
Q
If a person receives radiation exposure sufficient to cause the gastrointestinal syndrome, fatality occurs primarily as a result of
A
catastrophic damage to the epithelial cells that line the gastrointestinal track.
2
Q
For persons with hematopoietic syndrome, survival time shortens as
A
the radiation dose increases.
3
Q
Which of the following is not a form of acute radiation syndrome?
Carcinogenic syndrome
Hematopoietic syndrome
Gastrointestinal syndrome
Cerebrovascular syndrome
A
Carcinogenic syndrome
4
Q
The term LD 50/30 signifies the whole-body dose of radiation that can be lethal to
Correct!
A
50% of the exposed population within 30 days.
5
Q
Some local tissues suffer immediate consequences from high radiation doses. Examples of such tissues include
1. bone marrow.
2. male and female reproductive organs.
3. skin.
A
All options
6
Q
Atrophy refers to
A
shrinkage of organs and tissues after a high radiation dose is received.
7
Q
What determines the rate of production of chromosome aberrations?
1. The total radiation dose given to a somatic cell
2. The total radiation given to a genetic cell
3. The period of time in which radiation dose was delivered
A
All options
8
Q
In female oogonia, the ovarian stem cells
A
multiply to millions of cells only during fetal development.
9
Q
The correct order of development for the female germ cell from the stem cell phase to the mature cell is
A
primordial follicle, mature follicle, corpus luteum, ovum
10
Q
Which of the following are classified as early tissue reactions of ionizing radiation?
A
Nausea, epilation, and intestinal disorders
11
Q
The prodromal stage of acute radiation syndrome is actually the
A
beginning stage.
12
Q
Research has shown that repeated radiation injuries have a
A
cumulative effect.
13
Q
The hematopoietic form of acute radiation syndrome is also called the
A
bone marrow syndrome.
14
Q
Organ and tissue response to radiation exposure depends on factors such as
1. radiosensitivity.
2. reproductive characteristics.
3. growth rate.
A
All of the options
15
Q
A term that is synonymous with loss of hair is
A
epilation
16
Q
A single absorbed dose of 2 Gyt can cause a radiation-induced skin erythema within
A
24 to 48 hours after irradiation.
17
Q
In 1898, after suffering severe burns attributed to accumulated radiation exposure, this Boston dentist began investigating the potential hazards of radiation exposure and became the first known determined advocate of radiation protection was
A
William Herbert Rollins.
18
Q
The correct order of development of the male germ cell from the stem cell phase to the mature cell is
Correct!
A
spermatogonia, spermatocyte, spermatid, sperm
19
Q
Chromosomal damage can be caused by
A
both low and high radiation doses.
20
Q
During cardiovascular or other therapeutic interventional procedures that use high-level fluoroscopy for extended periods, the effects of ionizing radiation on the skin are at most
A
significant
21
Q
Moist and dry desquamation can be caused by
Correct!
A
high radiation doses
22
Q
Early tissue reactions are
A
not common in diagnostic imaging.
23
Q
Data from epidemiologic studies of human populations exposed to doses of ionizing radiation sufficient to cause acute radiation syndrome have been obtained from
1. atomic bomb survivors of Hiroshima and Nagasaki.
2. Marshall Islanders who were inadvertently subjected to high levels of fallout during an atomic bomb test in 1954.
3. nuclear radiation accident victims, such as those injured in the 1986 Chernobyl disaster.
4. patients who have undergone radiation therapy.
A
All options
24
Q
Grenz rays were once used to treat and successfully cure
A
skin diseases such as ringworm.
25
During the major response stages of acute radiation syndrome after the prodromal stage and a period of false calm that may last for several days, the stage when symptoms that affect the hematopoietic, gastrointestinal, and cerebrovascular systems occurs, this stage is called
manifest illness.
26
Radiation-induced cataracts in humans follow a ______ dose–response relationship.
threshold, nonlinear
27
Among the atomic bomb survivors, the number of people living with leukemia has _______________ since the late 1940s and early 1950s. However, the occurrence rates of other radiation-induced malignancies continued to ___________ since the late 1950s and early 1960s
slowly declined; escalate
28
To assess the magnitude and severity of late effects on the exposed population from the 1986 nuclear power station accident at Chernobyl
long-term follow-up studies are necessary
29
Which of the following late effects caused by exposure to ionizing radiation is considered to be most significant?
Cancer
30
The human body can incorporate radium into bone because it is chemically similar to
calcium
31
During the 1950s and 1960s, the Navajo people of Arizona and New Mexico who mined uranium for fuel for nuclear weapons and power plants developed lung cancer years after their exposure. This provides an example of which of the following?
Late stochastic effects
32
Laboratory experiments with mice conclude that cataracts may be caused by doses of ionizing radiation as low as
0.1 Gyt.
33
In which of the following human populations is the risk for causing a radiation-induced cancer not directly measurable?
All patients in diagnostic radiology subjected to a radiation dose below 0.1 Sv.
34
Mutations in genes and DNA that occur at random as natural phenomena are called
spontaneous mutations.
35
Existing data on radiation-induced genetic effects in humans
are both contradictory and inconclusive.
36
When a prediction is made that the number of excess cancers will increase as the natural incidence of cancer increases with advancing age in the population, the risk is considered to be
relative
37
What is the mean value of the radiation doubling dose for humans, as determined from studies of the children of the atomic bomb survivors of Hiroshima and Nagasaki?
1.56 Sv
38
Genetic effects from exposure to ionizing radiation occur as a result of radiation-induced damage to the DNA molecule in which of the following?
Sperm of a man
Ova of a woman
Somatic cells of men and women
Both A and B
Sperm of a man
Ova of a woman
39
What do agents such as specific chemicals, viruses, and ionizing radiation have in common?
They are all mutagens that can increase the frequency of mutations.
40
Which of the following are sources of low-level radiation exposure?
1. X-rays and radioactive materials used for diagnostic purposes
2. Employment-related exposure in medicine and industry
3. Natural background radiation
All options
41
During the preimplantation stage of development, the fertilized ovum divides and forms a ball-like structure containing undifferentiated cells. If this structure is irradiated with a dose in the range of 0.05 to 0.15 Gyt which of the following will result?
Embryonic death
42
After the Chernobyl disaster in 1986, an attempt was made to prevent thyroid cancer in Poland and some other countries, resulting from the accidental overdose of iodine-131. Physicians administered ______________________ to children as a harmless substitute to inhibit the gland’s uptake of iodine-131.
potassium iodide
43
Epidemiologic studies are of significant value to radiobiologists who use the information from these studies to formulate dose–response curves for making predictions of the risk of ____________ in human populations exposed to low levels of ionizing radiation.
cancer
44
Radiation-induced genetic abnormalities are caused by unrepaired damage to
DNA molecules in the sperm or ova of an adult.
45
Some mutations in genetic material occur spontaneously, without a known cause. In humans, a hereditary disorder is present in approximately _________ of all live births in the United States.
10%
46
Currently, evidence of radiation-induced hereditary effects has not been observed in persons employed in diagnostic imaging or in patients undergoing radiologic examinations. Even with this information, it is still recommended that
all radiation exposure be maintained as low as reasonably achievable (ALARA).
47
Radium decays with a half-life of
1622 years.
48
The term linear nonthreshold relationship implies that the biologic response to ionizing radiation is
directly proportional to the dose all the way down to levels approaching zero.
49
Genetic mutations at the molecular level are called
point mutations.
50
Studies of postpartum patients treated with ionizing radiation for relief of mastitis are a group of individuals in whom the results of radiation exposure to healthy breast tissue via scattered radiation indicate that radiation
can cause breast cancer
51
Which of the following terms involves a random effect of ionizing radiation?
Stochastic event
52
Upper boundary safe radiation exposure limits for occupationally exposed persons are associated with risks that are similar to those encountered by employees in other industries that are generally considered to be reasonably safe. These industries include
1. manufacturing.
2. trade.
3. government.
All options
53
Which of the following agencies was previously known as the Atomic Energy Commission?
NRC
54
Which of the following are functions and/or responsibilities of the United States Occupational Safety and Health Administration (OSHA)?
1. Functions as a monitoring agency in places of employment, predominantly in industry
2. Regulates occupational exposure to radiation through Part 1910 of Title 29 of the U.S. Code of Federal Regulations (29 CFR 1910)
3. Responsible for regulations concerning an employee’s “right to know” with regard to hazards in the workplace
All options.
55
Which of the following groups is run by the government of Japan, primarily to study Japanese atomic bomb survivors?
Radiation Effects Research Foundation
56
Epidemiologic studies of atomic bomb survivors exposed in utero have provided conclusive evidence of a dose-dependent increase in the incidence of severe intellectual disability for fetal doses higher than approximately
0.4 Sv.
57
Determine the cumulative effective dose (CumEfD) limit to the whole body of an occupationally exposed person who is 46 years old.
460 mSv
58
Revised concepts of the risks of radiation exposure have brought about changes in NCRP recommendations for limits on exposure to ionizing radiation over a number of decades. Because many conflicting views exist on assessing the risk of cancer induction from low-level radiation exposure, the trend has been to
create more rigorous radiation protection standards.
59
The primary function of the Nuclear Regulatory Commission (NRC) is to
oversee the nuclear energy industry
60
The effective dose (EfD) limiting system is
the current method for controlling the risk of biologic damage to radiation workers and the general public from radiation exposure.
61
The ALARA concept adopts an extremely conservative model concerning the relationship between
ionizing radiation and potential risk.
62
If a certain dose of radiation produces a skin burn, a higher dose of radiation will cause the skin burn to be more severe; however, a dose below the threshold level for skin burn will
not demonstrate the effect.
63
The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) evaluates human and environmental ionizing radiation exposures from a variety of sources, including
1. radioactive materials.
2. radiation-producing machines.
3. radiation accidents.
All options.
64
Which of the following are responsibilities of a health care facility’s administrative personnel to ensure an active and detailed radiation safety program?
1. Delegate operational funds in the budget for the radiation safety program
2. Oversee the development of policies and procedures the radiation safety program
3. Provide the equipment needed for starting and for continuing the radiation safety program
All options.
65
The essential concept underlying radiation protection is that
any organ in the human body is vulnerable to damage from exposure to ionizing radiation.
66
The cumulative effective dose (CumEfD) limit does not include
1. exposure acquired as a consequence of a radiation worker’s undergoing medical imaging procedures.
2. radiation exposure from natural background radiation.
3. radiation exposure received while radiographers perform imaging procedures on patients.
1 and 2 only
67
Which of the following statements is true?
Medical imaging personnel hardly ever receive equivalent doses that are close to the annual occupational effective dose limit.
68
Occasional exposure for the purpose of education and training is permitted, provided that special care is taken to ensure that the annual effective dose limit of ____________ is not exceeded for persons under the age of 18 years.
1 mSv annually
69
The effective dose (EfD) occupational limit for the lens of the eye is
15 mSv.
70
The responsibility for maintaining radiation monitoring records for all personnel and for providing counseling for individuals who receive monitor readings in excess of allowable limits belongs to the
designated radiation safety officer of a health care facility.
71
To provide a low-exposure cut-off level so that regulatory agencies may consider a level of effective dose as being of negligible risk, an annual negligible individual dose (NID) of ________________ per source or practice has been set.
0.01 mSv/year
72
A radiation safety officer in a health care facility must have sufficient authority, organizational freedom, and management prerogative to
1. identify radiation safety problems.
2. initiate, recommend, or provide corrective action.
3. stop unsafe operations involving by-product material.
4. verify implementation of corrective actions
All options.
73
To define ALARA, health care facilities usually adopt investigation levels, defined as level I and level II. In the United States, these levels are traditionally _______ to ______ the applicable regulatory standards.
one tenth; three tenths
74
Working in conjunction with their partners in other agencies, the FDA intends to take action to
1. promote safe use of medical imaging devices.
2. support informed clinical decision.
3. increase patient awareness.
All options
75
Effective dose (EfD) limits may be specified for
whole-body exposure.
partial-body exposure.
exposure of individual organs.
All options
76
All digital imaging devices are subject to certain artifacts such as
1. aliasing.
2. moirè patterns.
3. contouring.
All options
77
The protective tube housing serves as a shield against _____________________ entering the x-ray tube, thereby preventing electric shock while also facilitating the cooling of the x-ray tube.
the high voltage
78
If the luminance of the collimator light source is sufficient, the localizing light beam will be able to satisfactorily outline the margins of the radiographic beam on the area of clinical interest on
patients of all skin pigmentations.
79
When using digital fluoroscopy systems, making use of the last image hold feature can
be an effective dose reduction technique
80
What is the purpose of radiographic beam filtration?
To reduce exposure to the patient’s skin and superficial tissues by absorbing most of the lower-energy photons from the heterogeneous beam
81
Most fluoroscopic examinations employ a range of _____________ kVp for adult patients, depending on the body area being examined.
75 to 110
82
When performing a mobile radiographic procedure, to reduce the radiation exposure to the patient, the radiographer must use a minimal source-skin distance of at least
30 cm.
83
When a fluoroscopic image is electronically amplified by the use of an image intensification system, which of the following benefits results?
1. Increased image brightness
2. Saving of time for the radiologist
3. Patient dose reduction
All options.
84
Current federal standards limit entrance skin exposure rates of general-purpose intensified fluoroscopic units with maximum technique factors engaged to a maximum of ________________, as measured at the tabletop using an average phantom, with the image intensifier entrance surface at a prescribed 30 cm above the tabletop.
88 mGya/min
85
During a fluoroscopic examination, a resettable cumulative timing device measures the x-ray beam-on time and sounds an audible alarm or in some cases temporarily interrupts the exposure after the fluoroscope has been activated for what length of time?
5 minutes
86
During interventional procedures, high-level control fluoroscopy is employed, resulting in a _______________________ or entrance dose rate to the patient to allow the examination of smaller and lower-contrast objects that are not ordinarily discerned during standard fluoroscopy.
higher entrance exposure rate
87
When obtaining a dorsoplantar projection of a foot, which of the following types of filters should be used to provide a greater uniform density of the anatomy?
Wedge filter
88
Digital radiography systems offer several advantages over computed radiography. Some of these include
1. lower dose.
2. ease of use.
3. immediate imaging results.
4. manipulation of the image
All options
89
Total filtration of _______________________ for fixed x-ray units operating above 70 kVp is the regulatory standard.
2.5-mm aluminum equivalent
90
In digital radiography the number of different shades of gray that can be stored in memory and displayed on a computer monitor is termed
grayscale
91
In standard image intensification fluoroscopy, an x-ray beam half-value-layer (HVL) of 3 to 4.5 mm aluminum is considered acceptable when kVp ranges from
80 to 100.
92
Digital radiography images can be accessed
at several workstations at the same time, thus making image viewing very convenient for physicians providing patient care
93
When an exposed computed radiography imaging plate is ready to be processed, an imaging reading unit is used to scan the photostimulable phosphor imaging plate with
a helium-neon laser beam
94
Computed radiography, because of its higher exposure latitude, makes grid use on the pediatric population
less necessary than was previously believed.
95
Fluoroscopic devices are capable of subjecting the patient, the equipment operator, and other personnel near the fluoroscopic equipment to substantial doses of ionizing radiation. These devices include
1. C-arm fluoroscopes.
2. fluoroscopes on stationary equipment with HLC mode used for interventional procedures.
3. biplane interventional fluoroscopic systems.
All of the options
96
Of the following procedures, which involve extended fluoroscopic time?
1. Biliary drainage
2. Stent and filter placement
3. Urinary or biliary stone removal
All options
97
Luminance is determined by measuring the concentration
over a particular field of view
98
When generator settings are changed from one mA and time combination to another, the most that linearity can vary is
10%.
99
The control panel, where technical exposure factors are selected and visually displayed for the equipment operator, must be located
behind a suitable protective barrier that has a radiation-absorbent window that permits observation of the patient during any procedure.
100
Which of the following materials is commonly used in the tabletop of a radiographic examination table to make the tabletop as radiolucent as possible so that it will absorb only a minimal amount of radiation, thereby reducing the patient’s radiation dose?
Carbon fiber material
