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Rad Review

Terms in this set (282)

Tungsten (W) is the target material of choice because it has a
a. low atomic number, high melting point, and high thermal conductivity
b. high atomic number, low melting point, and high thermal conductivity
c. high atomic number, high melting point, and low thermal conductivity
d. none
d. none - it has a high atomic number, high melting point, and high thermal conductivity
When changing from half-wave to full-wave rectification, how are x-ray quantity and quality affected?
Both x-ray quantity and quality double
A step-up transformer changes voltage and amperage in the what way?
Voltage is increased, and amperage is decreased proportionally - because voltage and amperage are inversely related
The high-voltage side of the typical x-ray circuit contains the following principal parts:
1. step-up transformer
2. autotransformer
3. circuit breaker
4. filament transformer
5. rectifiers
1 and 5
Within the x-ray circuit, the electrical device that operates on the principle of mutual induction and serves to increase voltage and decrease current is known as the
step-up transformer
Of the four categories of mobile units, which type needs to be plugged into the wall yet produces the most consistent radiation output?
High frequency
The x-ray tube most efficiently operates on
unidirectional/DC
Characteristics of the primary x-ray beam include
lower intensity at the anode end
How much kV reduction can be expected using three-phase equipment compared to single-phase equipment?
10 kV
How does the voltage applied to the x-ray tube differ between single-phase and three-phase power?
With three-phase power, the applied voltage never drops to zero
How do the actual and effective focal spots differ in size?
The effective focal spot is smaller than the actual focal spot
Which of the following will occur when the focal spot size is decreased?
a. unsharpness decreases
b. unsharpness increases
c. spatial resolution decreases
d. spatial resolution increases
a and d
As the anode angle decreases,
1. heat dissipation is improved
2. image sharpness improves
3. the effective focal spot is smaller than the actual focal spot
4. the anode heel effect is emphasized
2, 3, and 4
Which generator is associated with an approximate 13% voltage ripple (87% actual voltage)?
Three-phase, 6 pulse
What percent of voltage ripple results in higher radiation quantity and quality?
1%
Choosing an mA station
1. determines the current
2. determines the number of electrons boiled off at the filament
3. determines the filament (small or large)
4. determines the resistance
all
Which of the following accounts for an x-ray beam's heterogeneity?
1. incident electrons interacting with several layers of tungsten target atoms
2. energy differences among incident electrons
3. electrons moving to fill different shell vacancies
all
In capacitor/condenser discharge mobile units, how is the kV affected during exposure?
It decreases
With AEC, the area of interest must be placed directly over the selected detectors in order to avoid
overexposure or underexposure
What is the factor of choice to adjust/correct IR exposure?
mAs
When using an AEC system, the backup time should be set at
150% of the expected exposure time
What is considered an "entrance type" AEC device?
Ionization chamber
What term describes the shortest exposure time that a particular AEC system can produce?
Minimum response time
The diagnostic x-ray range is approximately
1. 10 to 1,200mA
2. 0.001 to 10 seconds
3. 25 to 150 kVp
4. all of the above
4
When full-wave rectification is applied to three-phase current, a _____ ripple is produced
voltage
Thermionic emission occurs at the
filament
Driving the thermionic cloud from the negative side of the tube to the positive side of the tube requires
a large potential difference
An acronym can be helpful when preparing for an upcoming examination. An acronym is a ______.
Word formed by the first letters of a series of statements or facts
Positive beam limitation (QC testing) must be accurate within (+) or (-)
2% of the SID
To cover a 14z17 inch field size, at a 40" SID, a diagnostic x-ray tube should have an average target angle of
12 degrees
What percentage of target interaction results in the production of x-ray photons?
1%
Characteristic interactions may occur only when the incident electron interacts with
an inner shell electron
Bremsstrahlung radiation is associated with
the involvement of the nucleus (within the target material)
Which one of the following agencies is a regulatory agency responsible for protecting both the public and occupationally exposed individuals from the effects of ionizing radiation, by setting and enforcing laws?
NRC
Isotopes are considered
atoms with the same atomic number, but different atomic mass
If the distance between the individual and the source of radiation is doubled, the exposure to the individual will be reduced by a factor of
4
As the speed of the IR increases, patient dose
decreases
When considering the electromagnetic spectrum one can state the relationship between frequency and wavelength is
indirect
Which of the following items is considered to be matter?
Wet snow
When a beam-restricting device is used, technical factors may need to be _____ to compensate for the change in density
increased
Positioning the tube to coincide with the grid lines will
aid in the removal of scatter
When compared to analog imaging, computed radiography exhibits
wider exposure latitude
What is another name for protective isolation?
Reverse isolation
What keeps size distortion to a minimum?
Decrease OID and increase SID
Which of the following is NOT true of mAs in digital systems?
a. mAs no longer controls density
b. mAs determines patient dose
c. mAs is selected to provide sufficient quanta/intensity
d. mAs no longer controls the quantity of radiation that forms the image
d
The term windowing refers to changes in
a. brightness
b. LUT
c. contrast/grayscale
d. all
d
Which of the following describes the use of low kVp in a radiographic image?
a. high contrast
b. low contrast
c. wide exposure latitude
d. narrow exposure latitude
a and d
Which two of the following will represent a great difference between adjacent densities?
a. increased contrast
b. decreased contrast
c. high kVp
d. low kVp
a and d
Which of the following occurs when the kVp is increased?
a. increased absorbed dose
b. decreased absorbed dose
c. increased scatter radiation
d. decreased scatter radiation
e. increased conrtast
f. decreased contrast
b, c, and f
In digital imaging, as speed class increases
1. dosage increases
2. noise increase
3. deviation index decreases
4. image repeats increase
all
Which selection on the control console alters both absorption and transmission?
kVp
In which of the following are both primary photons and secondary photons produced?
1. characteristic interaction
2. bremsstrahlung interaction
3. compton interaction
4. photoelectric interaction
all
In what type of interaction does the scatter photon have equal energy to the incident photon?
classical interaction
In what type of interaction does the incident photon lose up to 1/3 of its energy?
compton interaction
A direct relationship exists between image brightness and
window level
Which interaction between x-ray photons and matter produces a characteristic ray?
photoelectric effect
Which of the major interactions between x-ray photons and tissue cells poses a radiation hazard to personnel?
compton scatter
Select the one incorrect statement from those listed below
a. x-ray equipment operated by single-phase power produces a 50% voltage ripple
b. high-frequency voltage generators use inverter circuits to convert DC into a series of square pulses
c. three-phase power utilizes three simultaneous voltage waveforms out of step with each other by 120%
d. x-ray equipment operated by three-phase 12-pulse power produces 4% voltage ripple
a
When the LP/mm sampling rate is the same/similar to the LP/mm resolution of the IP, the following type of artifact can occur
aliasing
For a given FOV, as matrix size incerases
spatial resolution increases
What kV range is usually recommended for most abdominal imaging?
70 to 85
With digital systems, as the operating speed class increases
a. patient dose increases
b. quantum noise potential increases
c. patient dose decreases
d. quantum noise potential decreases
b and c
Compared to film-screen imaging, digital systems are
a. less sensitive to low-energy radiation
b. more sensitive to low-energy radiation
c. less sensitive to scatter radiation
d. more sensitive to scatter radiation
b and d
A wider (increased) window width
a. decreases the range of densities
b. increases the image contrast
c. increases the range of densities
d. decreases the image contrast
c and d
What term describes the numeric value representing the IR exposure?
deviation index
From the following list, select the factors having an impact on image distortion
1. part thickness
2. x-ray tube angle
3. kV selection
4. IR placement
1, 2, and 4
How does mAs affect the digital receptor exposure?
it is directly proportional
Which technical factor is inversely proportional to the receptor exposure?
SID
What is the distribution of tissue densities and/or physiologic changes that are present in the anatomic part undergoing diagnostic study called?
Subject contrast
Which of the following increases as the matrix size increases?
1. image quality
2. network transmission time
3. digital storage space
all
The term that defines the number of shades of gray that can be displayed within a pixel is
bit depth
Which aspect of image quality does a grid influence?
contrast
What aspect of image quality will be affected by mAs?
Receptor exposure
What technical factor will cause no change in IR exposure?
focal spot size
When sampling electronic signals, which theorem refers to the sampling frequency being greater than twice the frequency/bandwidth of the input signal?
Nyquist frequency
What acronym describes the useful imaging area of the digital receptor?
FOV
What is associated with the IR's sensitivity and accuracy in converting incoming information to the image displayed on the output viewing device?
DQE
What term is used to describe the numeric value representative of the exposure the IR receives in digital radiography?
exposure indicator
If FOV increases, pixel size
increases
For a given FOV, as the matrix size increases
1. pixel size decreases
2. image quality decreases
3. spatial resolution increases
1 and 3
In digital imaging, a 2D array of numbers comprised of columns and rows is known as
a matrix
What is the term used to describe the picture elements within a matrix?
pixel
The abbreviation MTF represents what function of an imaging system?
modulation transfer function
The magnitude of the signal differences in the remnant beam that results from the differing absorption properties of the part describes
subject contrast
Select the factors having an effect on digital brightness
1, pixel bit depth
2. window width
3. window level
4. matrix size
5. pixel density
3
Select the factors that have an effect on digital image resolution
1. pixel density
2. window level
3. pixel pitch
4. matrix size
5. window width
1, 3, and 4
All of the following are related to spatial resolution except
a. motion
b. focal-spot size
c. OID
4. scattered radiation
4
All other factors remaining the same, if a 14x17" field is collimated to a 4"-sqaure field, the radiographic image will demonstrate
less receptor exposure
From the following list, select the 4 factors that can impact receptor exposure
1. part thickness
2. anode heel effect
3. workstation monitor
4. focal spot size
5. AEC photocell selection
6. pathology
1, 2, 5, and 6
From the following list, select the factors that are most likely to have an impact on image contrast
1. part thickness
2. pathology
3. anode heel effect
1 and 2
From the following list, select the factors that are most likely to impact image spatial resolution/image sharpness
1. focal spot size
2. kVp
3. OID
4. mAs
5. SID
1, 3, and 5
From the following list, select the factors that are most likely to impact image spatial resolution
1. part thickness
2. anode heel effect
3. pathology
4. SID
1 and 4
From the following list, select the 2 factors having the most impact on receptor exposure
1. focal spot size
2. SID
3. OID
4. kVp
2 and 4
From the following list, select the factors that can have a significant impact on receptor exposure
1. motion
2. beam restriction
3. protective filtration
4. grids
2 and 4
Select the factors having an effect on digital image contrast/grayscale
1. pixel bit depth
2. window width
3. window level
4. matrix size
5. pixel density
6. LUT
1, 2, and 4
Select the factors having an effect on digital image brightness
1. pixel bit depth
2. window width
3. window level
4. matrix size
5. pixel density
3
From the following list, select the factors that are most likely to have an impact on image contrast
1. motion
2. beam restriction
3. protective filtration
4. grids
2 and 4
The high-voltage side of the typical x-ray circuit contains the following principal parts
1. step-up transformer
2. autotransformer
3. circuit breaker
4. filament transformer
5. rectifiers
1 and 5
What is evaluated by using a line-pair test tool?
spatial resolution
Select the factors having an effect on digital image contrast/grayscale
1. pixel bit depth
2. window width
3. window level
4. matrix size
5. pixel density
6. LUT
1, 2, and 6
The greater the dynamic range
the higher the bit depth and the greater the number of shades of gray
What is the term used to describe the extent/number of exposure intensities an IR can accurately detect?
dynamic range
What is the term used to describe the volume elements (depth) within the matrix third direction ("z" direction)?
voxel
Select the one incorrect statement
a. if there are too few x-ray photons reaching the digital IR the resultant image will appear noisy/quantum mottle/graininess
b. exposure indicators (EI), expressed as S number, EI value, or IgM number depending on equipment type, indicate the acceptable range of exposure in digital imaging
c. precise/close collimation should be used with digital systems because excessive scatter causes histogram analysis errors
d. quantum mottle often occurs in CR imaging when using an IP that has not been used or erased for 48 hours or more
d
In digital imaging systems, what is the primary controlling factors influencing contrast?
LUT
Organize the steps during image acquisition in order from start to finish
1. The VOI is identified
2. the computer determines what section of the histogram will be included in the displayed image
3. the exposure received creates a histogram
4. the histogram is compared with a stored histogram for the anatomic part
3, 4, 1, 2
What post-processing term serves to suppress image noise?
Smoothing/low-pass filtering
The photoconductor generally used with a TFT array in direct capture digital imaging is
amorphous selenium
What is the term used to describe radiation dose and volume or irradiated tissue?
DAP
What is the post-processing function that removes bony structures or reduces the effect of scatter in order to increase image contrast?
subtraction/addition
Which post-processing function allows for the reversal of the image from a negative to a positive?
image inversion
What is the term that describes no data being collected from a damaged active matrix array?
dropped pixels
What is the processing function called that shows a graph of signal intensity values corresponding to a spectrum of pixel values?
histogram analysis
The component of HIS that functions to provide each modality work list, patient tracking, scheduling, and image tracking is known as
RIS
The comprehensive integrated system that is designed to manage medical, administrative, financial, and legal aspects of hospitals is known as
HIS
What is the exposure indicator in digital (cassetteless) systems termed?
Dose are product
The DAP meter that is used in digital imaging can be found right below what part of the x-ray tube system?
collimator
The digital imaging (DR or CR) post-processing function that allows the radiographer to add text to the image is called
annotation
Which of the following are the primary functions of PACS?
1. network communication between image acquisition modalities
2. specialty image processing and annotation
3. image storage
all
During CR image extraction, what is the device used to collect light emitted by storage plate phosphors?
photodetector
The action of materials that absorb x-ray energy and emit visible light in response is termed
scintillation
When trapped PSP electrons are scanned by a laser beam, electron energy is released via photostimulable
luminescence
What is used to erase the PSP?
strong fluorescent light
A characteristic displayed by certain materials that emit light when they are exposed to another type of light is known as
photostimulable luminescence
Select the one incorrect statement from those listed
a. PSPs must be erased after use to prevent any residual, or "ghost", image on subsequent images
b. either monochromatic helium neon gas lasers or a solid-state laser beam should be used to stimulate the PSP
c. the image plate houses and protects the PSP
d. the storage screens typically used in CR contain cesium iodide
d
Select the two correct statements
1. maximum spatial resolution is equal to the Nyquist frequency
2. the term "saturation" refers to underexposure of the PSP
3. an IP unused for 6 hours should be erased to avoid background radiation artifacts
4. FOV/matrix size formula is used to determine pixel size
5. programmed histograms are unavailable in digital x-ray equipment
1 and 4
What is the effect of TFT DEL size in cassetteless digital imaging?
the smaller the DEL size, the better the spatial resolution
What kind of image contrast results from a narrow/decreased window width?
increased/higher contrast
What is the relationship between sampling frequency of PSPs and spatial resolution?
as sampling frequency increases, spatial resolution increases
Arrange the following CR steps in order from first to last
read
stimulate
erase
exposure
expose
stimulate
read
erase
Arrange the following six layers of a PSP screen in correct order from front to back
reflective layer
phosphor layer
base
protective coat
lead
antistatic layer
protective coat
phosphor layer
reflective layer
base
antistatic layer
lead
Select the one incorrect statement
a. MTF refers to the ability of an imaging system to record images having high spatial frequency
b. background radiation artifacts may occur in CR imaging when using an IP that has not been used or erased for 48 hours of more
c. if a grid used in CR has a frequency dissimilar to the CR processor's scan frequency, aliasing effect can result
d. dynamic range refers to the ranges of exposures that may be captured by the detector
c
Select the one incorrect statement
a. a primary display workstation is one that is used for image interpretation
b. the higher/greater the bit depth in digital imaging, the lesser the number of gray shades
c. exposure field recognition errors usually occur from scattered radiation outside the VOI area, often as a result of improper alignment of part, x-ray beam, and IP
d. direct digital systems have a fixed spatial resolution that is determined by TFT detector element (DEL) size
b
In digital systems, the
smaller the pixel pitch, the better the spatial resolution
Manipulation of gray level values is associated with
lookup table and window width
Which device has greater sensitivity to light and provides a higher SNR and improved contrast resolution?
A CCD
What is described as a measure of the rate at which energy is transferred from ionizing radiation to soft tissue?
LET
The representation of reference luminance values that assess input intensities and assign predetermined VOI describes
lookup table
What will result as tube current increases?
an increase in x-ray photon quantity
What influences shape distortion?
1. tube
2. OID
3. part
4. SID
5. IR alignment
1, 3, and 5
What type of effects are described as: "those biologic somatic effects of ionizing radiation that exhibit a threshold dose below which the effect does not normally occur and above which the severity of the biologic damage increase"?
tissue effects/deterministic
An increase in mA is associated with
increased SNR
To check for ghost images, which quality control action should be taken?
process an unexposed receptor at a higher than normal gain setting to detect any residual signal that has not been removed during erasure
What will represent a great difference between adjacent densities?
increased contrast and low kVp
What cellular component has the greatest radiobiological significance?
DNA
Which of the following is not among the types of late effects of ionizing radiation exposure?
carcinogenesis
embryological effect
lifespan shortening
all are types
A rotor and stator are associated with the
induction motor
If a lateral lumbar spine were performed with the center detector selected and the spinous processes centered to the sensor, the resulting image is likely to be
underexposed
Artificial contrast agents can be introduced into the body in which ways?
injection and ingestion
Which of the major interactions between x-ray photons and tissue cells is most likely to occur with tissues having high atomic number?
photoelectric
Of the three tools used to measure the focal spot size - the slit camera, the pinhole camera, and the star pattern - which is the most commonly used?
slit camera
What SI term is used to measure the amount of energy transferred in air?
air kerma
Select the conditions that are likely to require an increase in exposure
1. atelectasis
2. gout
3. pneumonia
4.emphysema
5. osteochondroma
1, 3, and 5
In what two ways can we reduce the production of scattered radiation?
use of beam restriction and appropriate kV level
To most accurately measure part thickness for use of a technique chart, the caliper may be placed
1. at the location of the CR midpoint
2. at the thinnest portion of the area to be radiographed
3. at the thickest portion of the area to be radiographed
1 and 3
What interaction between x-ray photons and matter involves an outer shell electron and only partial transfer of energy?
compton scatter
Select the four correct statements
1. rapid acceleration of electrons at the anode results in the production of x-rays
2. x-rays have a biologic effect on living tissue
3. the nickel (Ni) or molybdenum (Mo) focusing cup functions to direct the electrons toward the anode's focal spot
4. x-rays have an ionizing effect on air
5. the application of high voltage serves to accelerate the electrons toward the cathode
6. x-rays travel in straight lines
7. x-rays are focused by the collimator shutters
2. 3. 4. and 6
From the following list, select the factors that are most likely to have an impact on image contrast
1. motion
2. beam restriction
3. protective filtration
4. grids
2 and 4
Causes of grid cutoff, when using focused moving grids, include
1. inadequate SID
2. x-ray tube off-center longitudinally with the lead strips
3. angling the beam in the direction of the lead strips
1
Which interaction between x-ray photons and matter is more likely to produce short-scale contrast?
photoelectric
Which interaction between x-ray photons and matter involves an outer shell electron and only partial transfer of energy?
Compton scatter
The SSD in stationary fluoroscopy must be at least
38 cm
The NCRP-recommended annual dose limit for the thyroid is
500 mSv
A shorter wavelength photon is associated with
higher frequency, higher energy, and increased ionizing potential
T/F In very few exceptional circumstances, the radiographer may be exposed to the primary/useful x-ray beam
F
High-level control fluoroscopic tabletop exposure must not exceed
200 mGya/min
The federally required minimum lead equivalent for lead aprons is
0.25 mm Pb equiv.
The name of the particularly radiosensitive male sex cell is
spermatogonia
What unit is used to describe ionization in air?
Gya
In which type of monitoring device do photons release electrons by their interaction with air?
Pocket dosimeter
Fluoroscopic total filtration must be at least
2.5 mm Al equiv.
What weighting factors are used to determine the sievert?
Wt and Wr
Who of the following is likely to be the most radiosensitive?
One-year-old child
Twenty-year-old young adult
Fifty-year-old adult
All are equally radiosensitive
One-year-old child
Which of the following terms is used for ionizing radiation-induced hair loss?
1. alopecia
2. epilation
3. desquamation
1 and 2
Which of the following types of radiation is produced when filament electrons strike structures other than the focal track within the x-ray tube?
1. scattered radiation
2. off-focus radiation
3. exit radiation
2
Fluoroscopic magnification mode
increases patient dose
What radiation exposure dose to the ovaries will result in temporary infertitlity?
2 Gy
Which of the following illustrates the inverse square law?
1. distance is a most effective protection from radiation
2. distance is a rather ineffective protection from radiation
3. as distance from the radiation source decreases, radiation decreases
1
Which interaction with matter contributes most to the absorption characteristics of the x-ray image?
Photoelectric
Select the effects more likely to occur from low radiation doses
Leukemia
Epilation
Cancer
Erythema
Infertility
Leukemia and cancer
What is a 35-year-old radiation worker's lifetime cumulative effective dose limit?
350 mSv
The active ingredient in optically stimulated luminescence (OSL) dosimeters is
aluminum oxide
Which of the major interactions between x-ray photons and tissue cells is responsible for most scattered radiation production in the diagnostic x-ray range?
Compton
Which of the major interactions between x-ray photons and tissue cells is a major contributor to patient dose?
Photoelectric
Radiation-induced reddening of the skin at a dose of 2 Gy is termed
erythema
A radiation worker can determine his/her lifetime cumulative effective dose (CumEfD) limit using what formula?
age in years x 10 mSv
What source of radiation exposure is related to the use of medical imaging?
Manmade
Which of the following statements is true regarding the control dosimeter that accompanies each shipment of personal radiation monitors?
1. it should be stored away from all radiation sources
2. it should be stored in the main work area
3. it should be used to replace an employee's lost monitor
1
List the following in order of decreasing radiosensitivity:
gonads
liver
lungs
skin
gonads, lungs, liver, skin
Which of the following may be used as a low-attenuating interspace material found between the radiopaque strips in a grid?
aluminum
lead
plastic fiber
wood
molybdenum
tungsten
aluminum, plastic fiber, and wood
When a lead apron is worn during a procedure, the personnel dosimeter should be placed
outside of the apron at collar level
In what type of interaction does the incident photon lose up to one-third of its energy?
Compton
What is the active ingredient found in a thermoluminescent dosimeter?
Lithium Fluoride
When a 1-mm Pb flat contact shield is used to shield female reproductive organs, their dose is reduced by about
50%
What represents the estimated dose to the gonads that, if received by the total population's gene pool, would produce the total genetic effect on the population as the sum of the individual doses actually received?
Genetically significant dose
Which of the cellular components has the greatest radiobiological significance?
DNA
The fluoroscopy timer must provide signal after how much fluoroscopic time has elapsed?
5 minutes
The most accurate personal dosimeter is
optically stimulated luminescence (OSL)
The bucky slot cover must have at least what lead equivalent?
0.25 mm Pb equiv
What effect does the presence of oxygen have on radiosensitivity?
it increases radiosensitivity
The intensity of scatter 1 m from the patient is about what percentage of the useful beam?
0.1%
Select the four correct statements from those listed below:
1. rapid acceleration of electrons at the anode results in the production of x-rays
2. x-rays have a biologic effect on living tissue
3. the nickel (Ni) or molybdenum (Mo) focusing cup functions to direct the electrons toward the anode's focal spot
4. x-rays have an ionizing effect on air
5. the application of high voltage serves to accelerate the electrons toward the cathode
6. x-rays travel in straight lines
7. x-rays are focused by the collimator shutters
2, 3, 4, and 6
The type of acute radiation syndrome (ARS) that requires the least amount of ionizing radiation dose to occur is
hematopoietic
No safe dose of ionizing radiation refers to
the linear no-threshold model (LNT)
Which term refers to the smallest dose of radiation that will produce a specific effect?
Threshold
What type of radiation mainly causes indirect damage to biologic tissues?
1. high-LET
2. alpha particles
3. gamma rays
4. low-LET
3 and 4
The effects of radiation that are directly related to the dose received, which can occur months or years after exposure, are called
acute deterministic somatic effects
What is the LD 50/60 for adult humans?
3 to 4 Gyt
The varied and specific biologic effects of whole body radiation exposure depend on several factors including
1. type of radiation
2. total dose
3. stage of cell division
4. time interval over which dose is received
all
Which of the following would result in a decreased radiation dose?
increased mA
decreased SID
increased kVp
decreased filtration
increased kVp
Microcephaly, intellectual disability, and central nervous system (CNS) anomalies can all result from radiation exposure to
embryos or fetuses
Which of those listed below have ionizing properties?
1. visible light
2. alpha particles
3. x-rays
4. microwaves
5. beta particles
2, 3, and 5
Which of the following are major types of acute radiation syndrome?
1. osseous
2. gastrointestinal
3. cerebrovascular
2 and 3
Which of the following can be affected by ionizing radiation?
1. skin
2. male/female reproductive organs
3. chromosomes
all
What type of effects are described as: "those biologic somatic effects of ionizing radiation that exhibit a threshold dose below which the effect does not normally occur and above which the severity of the biologic damage increases"?
tissue effects/deterministic
What minimum radiation dose is required in order for acute radiation syndrome (ARS) to occur?
greater than 1 Gyt
Organize the following electromagnetic radiations in order of longest wavelength to shortest wavelength
visible light
x-rays
microwaves
microwaves, visible light, x-rays
X-rays are electrically
neutral
Biologic material irradiated under hypoxic conditions is
less sensitive than when irradiated under oxygenated conditions
Which of the following cells are the most radiosensitive?
myelocytes
erythroblasts
megakaryocytes
myocytes
erythroblasts
Example of radiation-induced conditions that follow a linear nonthreshold dose-response relationship include
genetic effects
radiation-induced cancer
leukemia
all
What effect does the presence of oxygen have on radiosentitivity?
it increases radiosensitivity
Which of the following ionizing radiations has the highest LET?
alpha
beta
gamma
omega
alpha
Occupational radiation is
low energy and low LET
Erythema can be an effect of excessive ionizing radiation exposure to what body part?
1. skin
2. lens of the eye
3. chromosomes
1
The presence of oxygen affects cell/tissue radiosensitivity by
increasing it
In which portion of pregnancy is the embryo/fetus most radiosensitive?
the first trimester
What radiation exposure dose to the ovaries will result in temporary infertility?
2 Gy
What acronym serves as a reminder to the radiologic technologist to keep exposure to themselves and their patients to a judicious minimum?
ALARA
During mobile radiography, the source-to-skin (SSD) distance must not be less than
12"
The amount of energy deposited, and resulting possible biologic damage, are related to which 3 of the following:
1. type of ionizing radiation
2. type of target/focus material
3. mass density of tissue
4. atomic number of tissue
5. SNR
1, 3, and 4
What unit is used to describe occupational exposure?
Sv
What parts of the body should be shielded from the useful beam whenever possible?
The lens of the eye, the breasts, and the reproductive organs
Three different filters are incorporated into the detector packet of the optically stimulated luminescence dosimeter. Of what are these filters made?
Aluminum, tin, and copper
What instrument is called a cutie pie?
Ionization chamber-type survey meter
What type of dosimeter contains an aluminum oxide detector?
Optically stimulated luminescence dosimeter
Which of the following are advantages of the personnel digital ionization dosimeter?
1. instant access to reports
2. no waiting time for mailing dosimeters
3. lightweight and durable
4. can be dropped or scratched with little chance of harm to the device
all
Which components of the geiger-muller survey meter alerts the operator to the presence of ionizing radiation?
An audio amplifier and speaker
When changing employment, what must a radiation worker convey to his/her new employer?
Data pertinent to accumulated permanent equivalent dose to be placed on file
The digital ionization dosimeter provides an instant read-out of dose information when connected to a computer via a connector such as a
USB
Whenever the letter "M" appears under the current monitoring period or in the cumulative columns of a personnel monitoring report, it signifies that
an equivalent dose less than the minimum measurable radiation quantity was recorded during that time.
What term involves a random effect of ionizing radiation?
stochastic
Upper boundary 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
manufacturing, trade, and government
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
The main function of the Nuclear Regulatory Commission (NRC) is to
1. inspect imaging facilities
2. oversee the nuclear energy industry
3. regulate imaging facilities
2
The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) evaluates human and environmental ionizing radiation exposure from a variety of sources, including
1. radioactive materials
2. radiation-producing machines
3. radiation accidents
all
Which of the following are responsibilities of a health care facility's radiation safety committee (RSC)?
1. delegate operational funds in the budget for the radiation safety program
2. provide guidance for the radiation safety program
3. facilitate the ongoing operation of the radiation safety program
2 and 3
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
The non-occupational effective dose (EfD) limit for the lens of the eye is
15 mSv
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
Effective dose (EfD) limits may be specified for
1. whole-body exposure
2. partial-body exposure
3. exposure of individual organs
1 and 3
When a pregnant patient must undergo a radiographic procedure, what practice will minimize radiation exposure?
Selecting technical exposure factors that are appropriate for the part of the body to undergo radiography and precisely collimating the radiographic beam to include only the anatomic area of interest and shielding the lower abdomen and pelvis when this area does not need to be included in the area to be irradiated
Specific area shielding may be selectively used during some ex-ray procedures to protect which of the following?
1. lens of the eye
2. breast
3. upper extremities
4. lower extremities
1 and 2
_____ are the sensing devices most often used to measure skin dose directly
thermoluminescent dosimters
What must always be the first step in protection of the reproductive organs?
Adequate and precise collimation of the radiographic beam to include only the anatomy of interest
Motion controlled by will is classified as voluntary motion. Lack of such control may be attributed to which of the following?
1. the patient's age
2. breathing patterns or problems
3. physical discomfort
4. fear of the exam
5. mental instability
all
Reducing the field size to the anatomic features of interest not only reduces patient exposure, but also
increases recorded image quality by decreasing scatter
Which of the following x-ray procedures increases the radiographer's risk of exposure to ionizing radiation compared to radiography?
1. mobile C-arm fluoroscopy
2. interventional procedures that use high level control fluoroscopy
3. mobile radiographic exams
all
Occupational exposure of the radiographer can be kept as low as reasonably achievable (ALARA) through individual monitoring and other protective measures and the use of protective devices. Therefore, because exposure from radiation-related jobs will not alter the _____, radiation workers may receive a larger equivalent dose than members of the general population.
genetically significant dose
Which of the following are radiation-shielding design considerations?
1. the mean energy of the x-rays that will strike the barrier
2. whether the barrier is of a primary or secondary nature
3. the workload of the unit
4. the use factor of the unit
5. the occupancy factor behind the barrier
all
Whenever scattered radiation decreases, the radiographer's exposure
decreases
What is another term for use factor (U)?
Beam direction factor
The annual effective dose limit for individual members of the general population not occupationally exposed is _____ for continuous or frequent exposures from artificial sources other than medical irradiation and natural background radiation and _____ for infrequent annual exposure
1 mSv and 5 mSv
A protective curtain, or sliding panel, with a minimum of 0.25-mm lead equivalent should normally be positioned between the fluoroscopist and the patient to intercept what type of radiation?
Scattered radiation above the tabletop
For primary radiation, what is the term that represents a portion of beam-on time that the x-ray beam is directed at a primary barrier during the week?
Use factor
When a radiologic technologist declares her pregnancy to her employer, what is appropriate?
She continues to perform her duties without interruption of employment, provided that she has received radiation safety counseling and follows established radiation safety practices.
When doors to radiographic and fluoroscopic rooms are closed during radiation exposures, a substantial degree of protection is provided for persons in areas adjacent to the room door. This is because in most facilities room doors have attenuation for diagnostic energy x-ray equivalent to that provided by _______ mm of lead.
0.8
If the peak energy of the x-ray beam is 100 kVp, a protective lead apron must be the equivalent to at least which of the following measures?
A minimum if 0.25-mm lead equivalent
_____ is essentially the radiation output weighted time that the unit actually delivering radiation during the week
workload
Secondary radiation includes
1. leakage radiation
2. primary radiation
3. scatter radiation
1 and 3
The central nervous system syndrome occurs following a whole-body dose of _____ Gy or more
50
During the latent period, the radiation victim experiences
well-being
What would be the most likely immediate response to a whole-body dose of 2 Gy?
Diarrhea, nausea, and vomiting
The LD50/60 is the dose of radiation to the whole-body that will result in death within _____ to _____% of the irradiated population
60 days, 50
Death from acute radiation exposure follows a _____ dose-response relationship
nonlinear, threshold
Skin effects from localized doses of radiation follow a _____ dose-response relationship
nonlinear, threshold
During an imaging exam, what combination of technical exposure factors and filtration reduce patient radiation dose?
High kVp, low mAs, increased filtration
Dose limits are described as
effective dose
The tissue weighting factor has a higher value for tissues with more
radiosensitivity
The dose limit to the general public is
1 mSv/yr
Optically stimulated luminescent (OSL) monitors are superior to the thermoluminescent dosimeters in that they are
more sensitive to low exposure
The dose limit for a technologist during pregnancy is
0.5 mSv/mo
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