Question | Answer |
layers of intensifying screens | protective coating
phosphor
reflective layer or absorbing layer
base |
layers of films | supercoat
emulsion
adhesive
base |
thicker phorsphor | screen speed increase
recorded detail decrease
patient dose decrease |
larger phosphor crystal size | screen speed increase
recorded detail decrease
patient dose decrease |
reflective layer | screen speed increase
recorded detail decrease
patient dose decrease |
aborbing layer | screen speed decrease
recorded detail increase
patient dose increase |
dye in phosphor layer | screen speed decrease
recorded detail increase
patient dose increase |
when intensifying screens are used what % is light and what % is x-ray | 90 to 99% light and 1 to 10% is x-ray |
what are the rare earth elements | lanthanum oxybromide (blue)
yttrium tantalate (ultraviolet/blue)
gadolinium oxysulfide (green) |
density vs film speed | screen speed increases density increases
screen speed decrease density decrease |
how is film stored | film box stored vertically
temperature: 50 to 70 degrees F (10-21 degees C)
relative humidity: 40% to 60%
FIFO |
processing stages | developing-convert the latent image visible image
fixing-remove unexposed silver halide film
washing- remove fixing solution from surface
drying-remove 85% to 90% of moisture (10% to 15% moisture remain) |
artifacts | unwanted image on a radiography |
types of rollers | entrance roller
transport roller-move film through chemical tanks and dyer assembly
turnaround roller-located at bottom of roller assembly
crossover roller-move film from one tank to another |
squeegee | located between the wash tank and the dryer |
replenishment system | replacement of fresh chemicals after the loss of chemical during processin |
recirculation system | circulate the solutions in each of the developer and fixer tanks by pumping solution out of one portion of the tank and returning it to a different location within the same tank from which it was removed |
spectral matching | correctly matching the color sensitivity of the film to the color emission of the intensifying screen |
spectral emission | refers to the color of light produced by a particular intensifying screen |
spectral sensitivity | refers to the color of light to which a particular film is most sensitive |
what keep crystal suspended | gelatin |
spectral emission | calcium tungstate (bue)
gadolinium oxysulfide (green)
lanthanum oxybromide (blue)
yttrium tantalate (ultraviolet/blue) |
t-grain(tabular grain) | uses flat silver halide crystals instead of randomly shaped crystals; increases recorded detail |
what is the active ingredient of the radiographic emulsion | silver halide crystals |
linear grid | line run in one direction |
parallel grid | non-focused |
focused grid | lines are canted or angled |
crossed/cross-hatched | lead strips run both the length and width of the grid forming a criss-crossed pattern |
silver halide | material that is sensitive to radiation and light in the film's emulsion |
types of grids | wafer grid (tape on grid)
grid cassette
grid cap |
grid ratio increase | contrast increase
patient dose increase
likelihood of grid cutoff increase |
screen contact testing | hang film on view box
step back 72" from view box abd view film
areas of increased density or loss of resolution indicates poor contact or stained screens |
grid cutoff error | upside-down focused
off-level
off-center
off-focus |
grid ratio | height of lead strip divided by the width of the interspace |
grid frequency | express the number of lead lines per unit length, in inches, centimeters, or both |
beam-restricting devices | aperture diaphragm
cones and cylinders
variable aperture beam-limiting devices(collimators); PBL |
indirect conversion | the light interacts with a layer smorphous silicon |
direct conversion | exit radiation interacts directly with a layer of amorphous selenium |
TFT | thin film transistor-collection element where the electrical charge is stored until readout |
imaging plate | latent image conttains fluorohalide crystal |
fluorescence | emission of luight only during the stimulation of the phosphor; moment stimulation from radiation is stopped, light stop |
phosphorescence | with an afterglow duration; phosphors continues to emit light even after the stimulation |
luminescence | ability of a material to emit light in response radiation stimulation |
safelights | Kodak Wratten Series (orange-brown in
color)for ordinary blue-violet sensitive film
Kodak GBX(dark read) for green sensitive Orthro-G film |
Thinner or smaller crystal or decrease concentration of crystals (screen speed decrease or slow) | increase resolution
decrease density
increase patient dose |
thicker or larger crystal or increase concentration of crystals (screen speed increase or fast) | decrease resolution
increase density
decrease patient dose |
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