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RAD 120

Cumulative Final

QuestionAnswer
Regarding beam limitation, the size dof the x-ray beam should always be restricted to the __________ and collimation should be evident on ________ sides of the image. Region of interest, all 4
According to the NRC regulations the embryo/fetus does for the entire pregnancy cannot exceed ___ mSv, ___ rem or ___mrem. 5 mSv .5 rem 500 mrem
The ___ is a regulatory agency responsible for protecting both the public and occupationally exposed individuals from the effects of ionizing radiation. NRC
When no threshold dose for radiation exists, the effect is known as _____. Stochastic
_____ is a deterministic effect of ionizing radiation on the eyes. Cataracts
Radiation exposure limits pertinent to the protection of radiation workers are known as __________ limits. Dose equivalent
The annual effective dose limit for an occupational exposure to ionizing radiation is ___ rem. 5
The annual effective dose limit for an occupational exposure to ionizing radiation is ____ mrem. 5000
The annual effective dose limit for the general public to ionizing radiation is ___ rem. .5
What is the dose limit for a 21-year-old radiation worker? 21 rem
What are the three Cardinal Principles of Radiation protection? Time Distance Shielding
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 ____. Four
For an individual to reduce exposure by a factor of 25 the distance between the individual and source of ionizing radiation should be ________ Increased by a factor of five
Secondary barriers protect against _____ and _____. Leakage and scatter
List two protective devices. Gonadal shield Lead apron
Protective aprons and gloves are usually made of lead-impregnated vinyl within the range of _____ lead equivalency. .25 - 1.0 mm
For fluoroscopic procedures with a kVp of 100 or more, the protective apron must possess a minimum of ____ lead equivalent. .5 mm
Proper collimation _____ scatter radiation. Reduces.
Using techical factors where _____ kVp and _____ mAs are chosen minimizes patient dose. High Low
The NCRP recommends a minimum total filtration of _____ for x-ray equipment operating above 70 kVp. 2.5 mm al/eq.
The use of a grid in a radiographic procedure will result in a/an _____ in patient dose. Increase
Special gonadal shields should be employed any time the gonads are within _____ cm of the primary beam. 4-5
The lenses of the eyes will receive the greatest dose during the AP or PA skull procedure? AP skull
A fetus is most radiosensitive during _____ post-conception. 8-15 weeks
What does ALARA stand for? As Low As Reasonably Achievable
A compound filter uses ____ or more materials to enhance the absorbing ability of the filter. Two
The percentage of attenuated photons _____ as photon energy increases, even when filtration is increased. Decreases
When filtration is increased, technical factors must be _____ to maintain the same density. Increased
Total filtration is equal to the sum of _____ and _____ filtration. Inherent Added
Does filtration remove a portion of the useful beam? Yes
The _____ portion of a wedge filter is placed over the less dense part of the patient. Thickest
Any filtration that occurs outside the tube and housing is considered to be _____ filtration. Added
_____ filtration is the filtration found within the tube design. Inherent
In diagnostic radiology, filtration is typically added between the _____ and the patient. Source or tube
Filtration is the process of eliminating undesirable _____ x-ray photons by the insertion of absorbing materials into the primary beam. Low energy
Filtration permits the radiographer to _____ the photon emission spectrum into a more useful beam. Narrow or harden
Increased filtration _____ patient dose. Reduces
In general, low energy x-ray photons are _____ by the patient. Absorbed
Name three materials considered filters in the x-ray tube: Aluminum Glass Oil
The most common filter material used is _____. Aluminum
All filtration can be expressed in terms of _____. Al/Eq.
Define half value layer. The amount of material or filtration needed to reduce the beam to one-half of its original intensity.
The collimator is categorized as _____ filtration. Added
How many half-value layers must be added to the primary beam to reduce its intensity to less than 20% of its original value? 3
The problem of unequal subject density is solved by using a _____ filter. Compensation
_____ is the second of the two geometric properties affecting radiographic image quality. Distortion
Distortion is the _____ of the size or shape of the structures being examined. Misrepresentation
Distortion is directly related to _____. Positioning
What are the two types of distortion? Size (Magnification) Shape (Elongation/foreshortening)
Disortion always _____ and can only be _____. Exists, minimized
All size distortion is controlled by ___ and ___. SID, OID
Increased distortion, _____ resolution Decreases
Magnification size distortion is controlled by positioning the body part and tube to maximize ___ while minimizing ___. SID, OID
The greater the SID, the _____ the magnification. Smaller
The OID must be minimized to _____ magnification. Decrease
The ___ is the critical distance for magnification and resolution. OID
What examinations require a larger SID? Body parts with large inherent OID (Chest and lateral C-Spine)
Objects that are further from the IR will be _____ Magnified
How is the magnification factor calculated? M = SID/SOD
How is the actual size of an object calculated? O = I/M O = object size I = image size M = magnification factor
Shape distortion is the misrepresentation by _____ _____ of the actual shape of the structure being examined. Unequal magnification
_____ projects the object so it appears to be longer than it really is, while _____ projects it so it appears shorter than it really is. elongation, foreshortening
Elongation occurs when the _____ or the _____ is improperly aligned. tube, IR
Foreshortening occurs only when the _____ is improperly aligned. part
Changes in the tube angle cause _____, never _____. elongation, foreshortening
What are the factors that affect shape distortion? Alignment (CR, part, IR) Angulation (Direction, degree)
The body part and IR should be _____ to one another with the CR _____ to both. parallel, perpendicular
Any structure that is not positioned at the CR will be _____ because of the _____ of the beam. distorted, divergence
Increasing SID, _____ distortion and vice versa Decreases
Increasing OID, _____ distortion and vice versa Increases
Increasing patient thickness, _____ distortion and vice versa. Increases
Improper CR alignment, _____ distortion. Increases
Improper anatomical part alignment, _____ distortion. Increases
Improper IR alignment, _____ distortion. Increases
Improper direction of CR angle, _____ distortion. Increases
Improper degree of CR angle, _____ distortion. Increases
An effective method of reducing patient exposure is through accurate and effective _____. positioning
As compared to an AP chest, a PA chest decreases the _____ to the breast. exposure
As the primary-beam field size _____, the patient exposure decreases. decreases
As compared to an AP skull, a PA skull reduces exposure to the _____. lens of the eye
List three types of gonad shields flat contact, shaped contact, shadow
The radiation intensity from a diagnostic x-ray unit will vary in a/an _____ relationship with the square of the kVp. direct
Radiation intensity varies inversely with _____. distance
Entrance skin exposure is a/an _____ exposure. maximum
An increase in filtration results in a _____ in entrance skin exposure. decrease
The use of a grid will _____ patient exposure. increase
As film speed increases, patient exposure _____ when maintaining image receptor exposure. decreases
The patient has the right to _____ a radiographic examination ordered by the attending physician. refuse
The conscientious radiographer can reduce the patient dose by at least _____ in most examinations by choosing appropriate exposure factors. 50%
The maximum exposure received by the patient is at _____. the skin entrance to the body
Which of the following radiographic procedures delivers the lowest entrance skin exposure? a. hip b. pelvis c. lumbar spine d. elbow d. elbow
The Food and Drug Administration (FDA) sets an entrance skin exposure limit of _____ for fluoroscopic systems in the U.S. 11.5 R/min
The radiation intensity from a diagnostic x-ray unit will vary in a/an _____ relationship with the mAs. direct
To reduce patient exposure, the _____ kVp consistent with image quality should be selected. highest
Which x-ray generator will substantially decrease the patient entrance skin exposure? a. single-phase b. two-phase c. three-phase, 6-pulse d. three-phase, 12-pulse d. three-phase, 12-pulse
Patient entrance skin exposure decreases as SID _____. increases
When mAs is decreased, patient dose is _____. decreased
A decrease in subject part density will _____ scatter and _____ patient dose. decrease, decrease
What variables, other than the prime factors, can be used to reduce patient dose? filtration, decreased field size, gonad shielding
If OID _____, patient dose increases. increases
Most of the cones of the eye are located at the _____ in high concentration. fovea centralis
_____involves comparing mental images of patterns (anatomical, physiological, pathological and histological) to arrive at a diagnostic opinion. Pattern Recognition
Myopia is _____. nearsightedness
Hyperopia is _____. farsightedness
Presbyopia is _____. difficulty to focus on close objects
The fovea centralis creates a _____ at a viewing distance of about 9 inches. blind spot
All radiographic images are missing the critical diagnostic element of _____. depth
To view the human body in three dimensions, at least _____ image(s) is/are required. two
Radiography is useful in the _____ of art objects. restoration
Image _____ is formulated in the brain. perception
The specialized cells of the retina convert the visual image into _____. nervous impulses
The _____ nerve transmits visual neurological information to the brain. optic
When exposed to vast quantities of light photons, _____ is over-sensitized and becomes bleached out. rhodopsin
Rods and cones respond to _____. light
Photopic vision is controlled by _____. rods
Scotopic vision is controlled by the _____. cones
Rods function best in _____ light. dim
The visual phenomenon involving the perception of extremely small or faint details is termed the _____ threshold detection
The _____ occurs because the visual system has difficulty perceiving contrast differences that are distant from one another. boundary effect
The _____ occurs when the eye perceives a change in density. Mach effect
The phenomenon that occurs when the intensely bright light from a view box floods the eye directly is termed _____. veil glare
Contrast perception is dramatically increased when the eye uses a _____ motion, this movement maintains a constantly changing neurological signal, thus avoiding _____ of the optic nerves. scanning, saturation
the radiographic image is a _____-dimensional object. two
A radiographer can best minimize the amount of scatter radiation reaching the IR by ___________ the beam restricting/limiting
A ________ is placed between the pt and the ir to absorb scatter radiation grid
List 2 factors that affect the amount of scatter produced. kVp & irradiated material
Scattered photons from ____________ interactions are no use in demonstrating radiographic structures of interest. Compton
As more photons pass through the irradiated material unaffected, the resulting ir exposure has greater ________. contrast, b/c it's not being absorbed.
If an increase in kvp is accompanied by a reduction in mA, to maintain the same exit dose the overall result will be a ________ in scatter produced decrease
As the kvp increases, the % of x-rays that undergo a _______________ interaction will increase compton scatter
Penumbra is? a geometric unsharpness around the periphery of an image
Automatic collimators are known as _____________________. PBL (Positive Beam limitation) devices.
When more photons are absorbed photoelectrically, the resulting radiography has _______ density. less, b/c density is the blackening of the film so more white on an image means less density.
As the volume of irradiated tissue increases, the amount of scatter ___________ increases
The ______ the Z# of a material, the higher the number of PE absorption interactions will be and a __________ in scatter. higher, decrease
List 2 beam-restricting devices. collimators, cones, and cylinders
Why do higher z# materials have an impact on scatter? B/c the higher the z# the more PE absorption so the beam is less penetrable to the IR, so less scatter.
A small crystal size will produce _______ resolution and _______ speed. increase, decrease
The ejected halide electron is attracted to and trapped by a _______________ sensitivity speck
When the sensitivity speck traps a free electron, it becomes __________________ charged negatively
A negatively charged sensitivity speck attracts a free silver ______ or ________ ion, or cation
The unseen change in the atomic structure of the crystal lattice is called the ________ image latent
________________ film is sensitive to all colors. Panchromatic
Intensifying screens are used to: 1. Amplify the inome x-ray beam 2. Reduce patient radiation dose 3. Convert x-ray photons to light photons
What percentage of the latent image if formed by the light photons produced on the intensifying screen? 99%
What percentage of the latent image is formed by x-ray photons? 1%
To eliminate quantum mottle, increase _____. mAs
List the four layers of the intensifying screen: base, phosphor layer, protective layer, and reflective layer.
When an insufficient quanity of photons stikes the intensifying screen, quantum mottle will appear on the film as _____. grainy
When a phosphor is struck by an x-ray photon, it will emit _______. light photons
The active layer of the intensifying screen is the _____ layer. phosphor
The _____ of an intensifying screen is easily damaged by fingernails. protective layer
The type of interactions that takes place between the x-ray photons and the high Z number phosphor are ____ and ____. PE, Compton
The ability of the phosphor to emit as much ligh per x-ray photon interaction as possible is a measurement of the screen ____. speed
The precise wavelength of ligh emitted by the phosphor is termed the _______. spectral emission
The ability of a material to emit light in response to excitation is ______. luminescence
When light is emitted from a phosphor is delayed, it is called ____. phosphorescence
Delayed phsphoecent emission is called ____ or _____. sceen lag, afterglow
Intensifying-screen resolution is inversely related to: size of the crystals (larger crystals and a thicker layer decrease resolution)
Define resolution: ability to accurately image an object
A pentrometer is also referred to as a _____. step wedge
A penetrometer is excellent for monitoring ____ and ____. equipment, film/intensifying screen combinations
A densitometer is an instrument that provides a readout of _______. optical density
Identify the optical density formula: OD= log10 Io/It
The ability of film to stop light is termed _____. opacity
D log E curves are also known as _____ curves. characteristic, H&D, sensitometric
Important elements of the typical D log E curve include the: Dmax, straight line, shoulder, toe
The density at no exposure is termed the: base+fog
Film may expirience fog in the form of: heat, light and radiation
The toes of the D log E curve is controlled by: phenidone
The shoulder of the D log E curve is controlled by: hydroquidone
Where on the D log E curve is the majority of the diagnostic info found? straigh line (gamma, body)
The maximum density that the film is able to record is the: Dmax
Which point on the D log E curve represents the point where all the silver halide crystals have a full complement of silver atoms? Dmax
Additional exposre beyond Dmax reults in a a process known as: solarization
Which type of film is preexposed to Dmax so that additional exposure will cause a reversal to the image. duplication film
The primary characteristics of film include: speed, resolution, contratst and latitude
As crystal size increases, resolution _____. decreases
The amount of density a film produces for a given amount of exposure is termed the _____. film speed
The difference between adjacent densities is the _____. contrast
As the slope of the straight line increases, the contrast ____. decreases
As crystal size increases, film speed _____ increases
_____ is the range of exposures that will produce densities within the diagnostic range. Latitude
A dark radiograph has received too _______ photons and a light radiograph has too _________ photons. many, little
Why does increased beam restriction decrease density? Increased collimation/beam restrictions reduces how many photons can hit the IR therefore, reduces density, it's an inverse relationship
As the tissure density increases, radiographic density ______________. decreases
What happens if exposure conditions push into the toe or shoulder regions of a characteristic curve? There is a dramatic effect to density that isnt always solved with just doubling mAs bc the rules dont work on the extremes.
As SID increases, density _________ decreases
As OID increases, density ___________ decreases
As filtration increases, density ___________ decreases
Restricting the primary beam _______________ density. decreases
What is window leveling? adjusting the brightness/density on the image
Define film density. the degree of blackening on the film from silver halide deposits
The optical density range visible to the human eye is ________ to ________ .25 to 2.5
The ___________ factors should be used as the principle method for adjusting radiographic density. controlling
The controlling factor of density is _______ mAs
As mAs increases density __________ increases
The minimum change necessary to cause a visible shift in density is ________ of mAs. 30%
Which generator produces the least amount of density? single-phase, 2 pulse
The _________ is used as a guide to maintain the same density when kVp changes? 15% rule
Which factor influences the number of photons reaching the radiograph film? a. kvp b. mA c. time d. both b and c d. both b and c
which factor influences the average energy of photons reaching the radiograph film? kVp
the 15% rule changes _________ and maintains _______. contrast, density
Describe the relationship between exposure and SID. the inverse sq law
The ___________ of a radiographic image is visible because of sufficient contrast and sufficient density. detail
The difference between two adjacent densities is _________ contrast
A radiograph with ____ shades of gray exhibits high contrast few
The controlling factor of contrast is kVp
The range of density values that can be perceived by the human eye is called ________ contrast. visible
____________scale contrast provides the most information. Low/Long
As kVp increases, contrast _____________ decreases
___________ kVp causes density differences that were previously undetectable to become visible. Increase
As Compton scatter __________, contrast decreases. increases
As body part thickness ________, contrast increases decreases
As field size decreases, contrast ___________ increases
A radiograph that demonstrates considerable differences between densities is called _______ contrast. short scale
As the slope of the D log E curve ___________, contrast increases increases
_________ controls the relationship between photoelectric versus Compton interactions. Kilovoltage
Milliampere-seconds _________ contrast. influences
Image receptor contrast is expressed as the ______ of the D log E curve. slope
As grid ratio increases, contrast _________ increases
The primary method for adjusting contrast with digital imaging systems is through _______________ manipulations. window width
As _____ increases, a wider range of photon energies is produced kVp
The concept of contrast as it is displayed on a soft-copy monitor for digital images is described as ________ dynamic range
Which of the following interactions has a significant impact on the x-ray? photoelectric absorption
As the atomic number of an element increases, the energy required to remove an inner-shell electron ___________ increases
When a photon is ________, all of the energy is transferred to the matter. absorbed
As x-ray photon energy increases, the penetrating ability of the photon _________. increases
As mAs increases, x-ray exposure increases and radiographic film density _________. increases
Define radiographic film denisty: the degree of blackening of x-ray films
Exposure time is __________________ to the number of electons crossing from cathod to anode. directly proportional
Kilovolage has a ______ impact on radiographic density. profound
X-ray intensiy is ____ proportional to source to image receptor distance. inversely
As distance decreases, intensity ______ and film density _____. increases; increases
The factors that affect x-ray emission under the direct contol of the radiograher are called the _____ factors prime
When a photon is __________, it no longer exists. absorbed
During ____________, interaction, the energy released during the filling of the inner shell is known as secondary radiation. photoelectric
During photoelectric interaction, the incident x-ray photon must be greater than the _______ energy of the inner-shell electron. binding
Which of the following interactions has a significant impact on the x-ray image? compton scattering
What are the prime factors? KVP, mAs and distance
Quanity, intensity and x-ray output is directly affected by ____. mAs
X-ray quality is numerically represented by the ____. HVL
_____ and _____ are factors that directly affect x-ray quality. kvp; filtration
If 1 coulomb is equal to 6.3*10(18) electrons per second, how many electrons flow from cathos to anode in 1 second? 6.3x10(18)
If 1 ampee equals a flow of 6.3x10(18) electrons per second, how many electrons flow from cathode ot anode in 1 milliampere? 6.3x10(15)
As the mA doubles, the number of electrons flowing from cathode to anode _____. doubles
The primary controler of x-ray quantity is goverened by ____. mAs
If the mAs of a radiograph is increased from 10 to 20, the resulting radiograph will exhibit: increased density
If the mAs used to create one image is the same as the mAs used to create a second image of the same structure, then both images should have the same ____. density
Increasing the kVp on an x-ray control panel will cause an increase in the ____ of the electrons across the x-ray tube. speed
Increasing the energy of an incident electron will result in the production of an x-ray photon with ____ energy. high
If kVp is doubled, the amount of x-ray photons approximately increase 4 fold
Kilovoltage is the primary controller of _____. contrast
An increase in kVp by 15% will cause an approximate _____ in the exposure. doubeling
Adjustments in kVp should be used to control radiographic _____. contrast
X-ray intensity is measured in _____. roentgen (R)
In the human body, _______________ is the predominant interaction through most of the diagnostic x-ray range. photoelectric absorbtion
During _________ scattering, no energy is transferred in the interaction. coherent
What intercation with matter results in a radiograph with a short scale of contrast? ____________ photoelectric
when a scattered photon is deflected back toward the source, it is traveling in the directionopposite to the incident photon and is called ___________ radiation. back scatter
During ______________, the negatively charged electron is termed a negatron. pair production
what interaction with matter results in a radiograph with a long scale of contrast? compton
As _____ increases, the total number of photons transmitted without interaction increases. kvp
The relationship between the intensity of radiation and distance is the ______. inverse square law
The density maintenance formula is a _____ law. direct square
As the electons shells move farther form the nucleus, total electron energies _____ and binding energies _____. increase decrease
When an xray phton with a slightly greater than the binding energy of the inner shell electon interacts with that inner shell electron, a ____ interaction occurs. photoelectic
During Compton scattering the incident photon energy is divided between the ______ and the ____. ejected electron; scattered photon
An interaction that occurs between very low energy x-ray photons (approx 10 keV) and matter is called _____ scatter.
As kvp increases, the percentage of _______ interactions increases. compton
When an x-ray passes through matter, it undergoes a process called ___________ attenuation
During the process of attenuation, x-ray photons in the beam a) reduce in number b) lose energy c) interact d) alll of the above all of the above
During __________ the x-ray photon is converted to matter in the form of two electrons? pair production
Which atomic shell possesses the highest binding enegy? k-shell
unwanted densities caused predominantly by scattered photons are called ________ radiation fog
which energy-level electrons possess the highest total energy? a)K b) L c) M d) N N
when x-ray photons interact with matter and change direction, the process is called _________ scatter
if a photon interacts with matter and scatters, the photon exists with _________ energy. less
during photoelectric absorption, a/an __________ shell electron is ejected k
the photon that exits the atom after a Compton scattering is called the Compton ________ photon. recoil
the elctron dislodged during Compton scattering is called the ________ electron recoil
During the photoelectric interaction, as an electron transfers from an outer shell to a vacant inner shaell, energy is released in the form of _________________ secondary radiation/ characteristic
_____________ is the source of occupational exposure. compton scatter
compton scattering occurs when an incident x-ray photon interacts with a ___________ loosely bound outer shell
an interaction that occurs between very low energy x-ray photons (approx.10 keV) and matter is called ___________ scatter. a) coherent b)classical c) unmodified d) all of the above all of the above