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66 Cards in this Set
- Front
- Back
What exactly is an x-ray. A particle, a molecule, energy, or an atom?
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energy
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What is radiology?
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the study/diagnosis of radiographs
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What is radiography?
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the production of a radiograph
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What does kV stand for?
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kilo voltage
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What does mAs stand for?
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milli amps per second
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Which one of these controls the penetration power of the x-rays?
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kV
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Which one controls the number of x-rays/quality of the radiograph?
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mAs
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Which would need higher exposure factors, a 5cm thick cat chest or 5cm thick dog paw?
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5cm thick dogs paw
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What are the two elements contained in the emulsion layer of an x-ray film. Silver (Ag), lead (Pb), chlorine (Cl), or bromine (Br)?
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Silver (Ag) and bromine (Br)
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Chemically, what happens to the x-ray film in the developer solution?
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Exposed AgBr separates and the Br is washed off the film leaving the Ag (which appears black)
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chemically, what happens in the fixer solution?
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Unexposed AgBr is washed away leaving a clear space on the film
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if you took an x-ray on an upside down cassette, what would the resulting radiograph be like. All black, all white, no change – normal x-ray?
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all white
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what is contained in the intensifying screens?
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crystals that fluoresce when exposed to x-rays
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What is the purpose of intensifying screens?
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to decrease exposure factors needed
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when are intensifying screen not used (non-screen films)?
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dental x-rays
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name two ways to identify an x-ray film
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Pb tape, photo imprinting, light pen, sticky labels
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what position would a patient be in if you were about to take a VD x-ray?
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Dorsal recumbancy
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what does ‘to cone down’ or ‘collimate’ mean?
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To reduce the x-ray area to as small as possible
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what is fogging and give one cause.
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Is a spreading blackness over an area of the film. It is caused by light or x-rays reaching an unexposed x-ray film, ie cassette not closed properly, lid not put back on film box properly, loaded cassettes kept in x-ray area
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name two conditions for proper storage of x-ray film.
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cool, in original box, lid on, fridge (if high humidity), vertical, dry, dust free, use before expiry date
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Film to dark
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Overexposure due to to much kVp of mAs.
Overdevelopment due to too much time in developer or increased developer temperature. Overmeasurement of part under examination. Machine (meters or timer) out of calibration. SID (source image distance) not correct for grid use. |
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Film to light
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Underexposure due to insufficient kVp of mAs.
Underdevelopment due to decreased temperature or time of development, developer exhausted of diluted. X-ray tube failure. Incorrect film-screen combination. Machine timer out of calibration. Drop in incoming line voltage. |
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Film gray/lack of contrast
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Too much kVp.
Radiation fog due to exposure of film to radiation other than desired exposure. Light leak in darkroom. Storage fog due to conditions that are too hot of too humid. chemical fog due to old chemicals, increased chemical temperature, or increased time of development. Film out of date. Lack of a grid with use of high kVp. Double exposure. Incorrect bulb wattage or filter for safelight in darkroom. |
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Lack of detail
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Increased object-film distance.
Blurring due to poor screen-film contact. Blurring due to patient motion. Blurring due to x-ray tube motion. Distorted image due to central x-ray not directed at centre of film. Double exposure. |
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Heavy lines on radiograph (generalised)
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Grid lines due to:
Grid out of focal range. Grid out of alignment to x-ray central beam. Grid upside down. Damaged grid. Roller marks as result of film jammed in automatic processor. |
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Inconsistent film density
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Collimation of primary beam. Bucky tray not positioned directly under primary x-ray beam.
Cassette not locked in Bucky tray correctly. Light leak into cassette. Quantum mottle. Target damage (pitted anode). Variable screen-film contact. |
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Black marks (not genralised)
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Crimping or folding of film.
Two films ticking together during development. Static electricity. Developer on film bfore processing. Fingerprints as a result of developer on hands while loading or unloading cassette. |
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Clear areas on filem (white marks; not generalised)
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Hair in cassette.
Scratch in film emulsion. Line due to scratch on screen surface. Contrast medium on cassette or table. Air bubble on film during developing procedure. Film touching side of tank during manual processing. Fingerprints due t film handling with contaminated hands. Fixer splashes on film before developing. |
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Yellow radiograph
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Premature age due to improper fixation.
Film sticking together during fixing process. Incomplete washing so that residual fixer oxidises to yellow powder while destroyng the image. |
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Film to dark
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Overexposure.
Overdevelopment. |
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Film to pale
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Underexposure (background black but image too light).
Underdevelopment (background pale). |
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Patch film density
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Developer not stired.
Film not agitated in developer. |
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Contrast to high (soot and whitewash film)
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Kilovoltage too low.
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Contrast too low (flat film)
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Overexposure.
Underdevelopment. Overdevelopment. Fogging. |
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Fogging
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Scattered radiation from patient.
Scattered radiation from elsewhere. Exposure to white light before fixing stage. |
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Image Blurring
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Patient movement.
Tube head movement. Cassette movement. Scattered radiation. fogging. Poor screen - Film contact. Large OFD. |
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Dorsal
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Towards the spine or back surface.
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Ventral
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Towards or near the lower body surface, or belly, includes the under surface of the neck and tail.
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Cranial
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Closest to the head or cranium.
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Rostral
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On the head towards the nose.
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Caudal
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Towards the tail.
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Palmar
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The under surface of the front paws.
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Plantar
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The under surface of the paws on the hind legs.
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Proximal
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Towards the centre or origin, only relavant to limbs.
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Distal
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Furthest away, only relavant on limbs.
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Superior
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Top Jaw
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Inferior
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Bottom Jaw
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Lateral
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Towards the side away from the midline
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Mediolateral
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From inside to out, relavant to limbs only.
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Recumbent
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Lying down, unable to stand.
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Density
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Degree of blackness = mAs
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Contrast
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Visable difference in two adjacent tissues = kVs
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Good film
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White bone, good variety of greys, organ differentiation and background is black.
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mAs control
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the total number of x-rays produced.
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kVs control
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the penetrating power.
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What does a grid do?
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decreases scatter radiation.
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Radiographic contrast is defined as?
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Density difference between two areas of a finished radiograph
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Radiographic contrast is affected primarity by the?
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kVp. The higher the kVp, the lower the contrast.
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Intensifying Screens with Large crystals
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are faster - less detail - high grain.
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Intensifying Screens with Small crystals
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are slower - more detail- low grain.
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Intensifying Screens are?
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sheets of luminescent phosphor crystals mounted on the inside of the cassette that fluoresce when hit by x-rays to increase the exposure of the film.
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Technique chart advantages
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Save time.
produce quality radiographs. Prevents the need for a second radiographs due to inappropriate exposure factors. |
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Technique charts is made up based on.....
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the thickness of the tissue and anatomic area of the body that your are radiographing.
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SID
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Source - image distance.
distance from xray tube to film in the cassette. |
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Sante's rule
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(2 x tissue thickness in cm) + 40 inches (SID) + grid factor = kVp
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Line Voltage
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a compensator like a regulator on a o2 bottle. With out this the filament in the compensator will be destroyed. It regulates the amount of electricity to the filament.
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