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57 Cards in this Set
- Front
- Back
What is the wavelength range for x-rays?
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0.01 to 10nm
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T or F
Wavelength has no effect on x-ray energy. |
False. Shorter wavelengths afford greater energy.
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What three things modulate x-ray absorption in a tissue?
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Tissue density (eg: bone vs fat)
Atomic # of elements in the tissue Thickness of tissue |
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What are the 5 radiodensities?
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1 - air
2 - fat 3 - water (soft tissue) 4 - bone 5 - metal |
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What are the main parts of a radiograph machine?
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Generator
Control panel Tube (anode + cathode) |
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What parameters can usually be controlled at the control panel of a radiograph?
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on/off
mA (current in milliamperes) kVp (energy in peak kilovolts) s (time in seconds) |
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The total number of electrons crossing the tube describes the_________ parameter.
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mA (current)
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Increased x-rays is a result of increasing which parameters?
kVp mA mAs s |
Any one of these will increase x-rays
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Increased median x-ray energy is a result of increasing which of the following parameters?
kVp mA mAs s |
kVp
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What components are necessary to produce x-rays?
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source (cathode)
accelerating device target (anode) |
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What material comprises the source in most medical radiograph machines? What material comprises the target?
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Source (cathode) = W
Target (anode) = W on top of Cu (for heat dissipation) |
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This graph depicts an increase in which of the following parameters:
kVp mA mAs s |
mA
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This graph depicts an increase in which of the following parameters:
mA mAs kVp s |
kVp
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What are the two main types of x-ray radiation?
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Bremsstrahlung radiation
Characteristic radiation |
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Choose characteristic or Bremsstrahlung radiation...
...characterized by discrete energy peaks. |
Characteristic radiation
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Choose characteristic or Bremsstrahlung radiation...
...energy produced by the deceleration by a second charged particle. |
Bremsstrahlung radiation
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Choose characteristic or Bremsstrahlung radiation...
...radiation in a continuous background spectrum. |
Bremsstrahlung radiation
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Choose characteristic or Bremsstrahlung radiation...
...energy released when electrons from an outer energy level drop to a lower energy. |
Characteristic radiation
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Match the kVp value (low, medium, high) to the part being radiographed.
Fast moving structure Distal extremity Shoulder region Pelvic region Thorax Slow or non-moving structure |
Fast moving structure - high
Distal extremity - low Shoulder region - medium Pelvic region - medium Thorax - high Slow or non-moving structure - low |
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What is the range for low kVp? Medium? High?
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low = 45-60
med = 65-75 high = >80 |
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What are two major problems with scattered radiation in radiography?
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Safety concern
Reduced image quality |
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What are some techniques used to minimize scatter in order to achieve better image quality?
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Reduce area of tissue irradiated
Add Pb layer under cassette Use a grid Use higher kVp |
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What unit denotes the absorbed dose of radiation? What is this unit equal to?
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Gray (Gy) = 1 joule/kg
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What unit denotes the rate of radioactive decay? What is this unit equal to?
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Becquerel (Bq) = 1sec^-1;
also a Curie |
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What unit denotes the ability of radiation to ionize air? What is this unit equal to?
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Roentgen (R) = 2.58E^(-4) C/kg
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What unit measures the dose equivalent? What is this unit equal to?
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Sievert (Sv) = Gray x q.f. = 100rem
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Which of the following are sources of radiation?
a) Cosmic radiation b) Background radiation in food c) Xe gas d) Medical radiographs e) Weapons fall-out; nuclear reactor accidents f) Old orange fiestaware |
All of the above are EXCEPT for the Xe gas...try Rn gas instead!
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What is the non-occupational exposure legal radiation limit?
What is the occupational exposure legal radiation limit? Occupational limit if pregnant? |
non-occupational < 100 mem/yr
occupational < 5 rem/yr occupational/preggo < 500 mrem/yr |
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What are the 3 sources of radiation in radiology?
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Scattered radiation
Primary Beam Leakage from x-ray tube |
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What are the 2 ways of monitoring radiation exposure?
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Film badges
TLD (thermoluminescent detector) |
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What is the ALARA principle?
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As Low As Reasonably Achievable
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Which are ways to minimize radiation exposure to the radiographer?
a) use barriers b) use lead body shielding c) stand far away d) manually restrain patient to minimize necessary exposures |
A B and C are correct
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What is contained inside the cassette?
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screen + film
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What information should be entered in pre-processing of radiographs?
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Name of owner
Name of animal Date Marker (L vs. R) Clinic Vet/vet tech |
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What information should be entered in post-processing of radiographs?
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NONE! post processing is NOT ok!
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What term describes the degree of blackening of the film?
Which parameter has the MOST effect on this? |
Radiographic density; mA (or mAs)
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What term describes the range of gray shades on a film? Which parameter has the MOST effect on this?
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Contrast; kVp
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The amount of detail in a radiograph is known as...
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...resolution
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What are the three types of radiography?
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Conventional
Fluoroscopy Digital |
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What are the 2 types of digital radiography?
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computerized and direct
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T or F:
In computerized radiography, there is no need for a film cassette. |
False! This describes direct digital radiography.
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What is the universal diagnostic imaging file format extension?
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.dicom
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What are the 6 Rotengen signs?
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Number
Position Size Shape Opacity Margination (architectural pattern) |
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What is the minimum number of views that should be taken?
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2
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Doubling the mAs is equivalent to what change in kVp?
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increasing kVp by 15%
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Decreasing kVp by 27.75% (2 15% reductions) is equivalent to what change in mAs?
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decreasing mAs by 3/4
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What will be the impact on latitude, blackness, and contrast when...
...increasing kVp by 15% and decreasing mAs by 50%? |
latitude - increase
blackness - no change contrast - decrease |
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T or F:
Increasing kVp increases contrast. |
False! It decreases contrast (reduces the shades of gray)
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What will be the impact on latitude, blackness, and contrast when...
...decreasing kVp by 15% and increasing mAs 100%? |
Latitude - decrease
Blackness - no change Contrast - increase |
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When should a grid be used (ie, what is the cutoff thickness)?
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>11cm
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T or F:
Photographic film is very sensitive to x-ray exposure. |
False!
Actually, only ~10% of film exposure is due to directly to x-rays. |
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T or F:
There is no way to discern if a structure is above or below another structure in a single radiograph. |
True (mostly)...
This is why you need 2 views. You can, however, use the magnification effect to determine which structures are farther from the film. |
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What are the four common radiographic views of the equine carpus?
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DP
Lateromedial Medial oblique Lateral oblique |
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ID this radiographic view of the equine carpus.
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Dorsopalmar
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ID this radiographic view of the equine carpus.
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Medial oblique
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ID this radiographic view of the equine carpus.
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Lateral oblique
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ID this radiographic view of the equine carpus.
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Lateromedial
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