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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.
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According to the NRC regulations the embryo/fetus does for the entire pregnancy cannot exceed ___ mSv, ___ rem or ___mrem.
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RAD 120
Cumulative Final
| Question | Answer |
|---|---|
| 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 |
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