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33 Cards in this Set
- Front
- Back
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Increase Geometric Unsharpness
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1) Increase Focal Spot
2) Increase OID 3) Increase SID |
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Increase Quality Beam
(Penetrability) |
Increase kVp
Increase Filter |
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Increase Detail
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Slower
Increase RD Decrease FS Increase SID Decrease OID Direct exposure (vs slower intensifying screen) |
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Increase Contrast
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Decrease kVp
Increase Grid Shortest Scale |
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Decrease Patient Dose
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Increase kVp
Decrease mAs Decrease Grid Faster |
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Increase Density
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Increase kVp
Increase mAs Decreae SID Decrease Grid Fast |
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Increase Magnification
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Decrease SID
Increase Grid Increase OID Table top vs bucky |
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Increase Secondary Radiation Fog
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Increase kVp
Decrease Grid |
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Increase Recorded Detail
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*Decrease FS
Decrease OID Increase SID Decrease Motion Decrease Parallax Effect Single Emulsion Decrease Thickness Decrease size of Crystal Decrease Speed |
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Visibility of Detail
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1) Change mAs, kVp
2) Collimation (Decrease Scatter & Fog) 3) Processing Temperature 4) Filtration |
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Increase kVp
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Decrease Wavelength
Increase Penetration Decrease Absorption Increase 2nd radiation / scatter Increase Fog Increase Remnant Decrease Contrast Increase Grays Increase Density Long Scale Contrast Decrease pnt dose |
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Under-exposed Image
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1) SID
2) Thickness of Part 3) Grid Ratio 4) Beam Restriction |
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Over-exposed Image
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1) Increase mAs
2) Increase kVp 3) Development Time 4) IR 5) Decrease SID 6) Over Collimate 7) Improper centering (AEC) |
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Increase Mottle
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Increase kVp & Fast Film / Screen
(This decreases photons (mAs) -> Creates Noise) |
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Decrease Beam Size (collimation)
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Decrease Density
Increase Contrast Increase Visibility Increases Quality |
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Add Grid
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Decrease Density
Decrease Contrast Increase kVp Increase patient dose |
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Direct Exposure
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Decrease Density
Decrease Contrast Increase kVp Increase RD Increase pnt dose Long Scale Contrast |
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AEC
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1) "+" Increases exposure time
(Larger Pnt or Muscular) "--" Decreases exposuretime (Small or Frail) 2) Select Correct Chambers 3) Correct Position over desired cell |
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Magnification Factor Formula
(MF= ?) |
MF = Image / Object
or MF = SID / OID |
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15% Rule
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Decrease kVp by 15% & 2x mAs
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SID --> New mAs = ?
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new mAs= Old mAs x
d2(square) -------------------------- d1 (squared) |
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Grid ---> New mAs = ?
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New mAs = old mAs(grid2/ grid1)
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mAs Conversion Factor
Grid-> 5:1 6:1 8:1 10:1 12:1 16:1 |
5:1 (x2)
6:1 (x3) 8:1 (x4) 10:1 (x5) 12:1 (x5) 16:1 (x6) ex: 8:1 to nongrid--> (increase mAs 4x) nongrid to 8:1 --> (decrease mAs by 4) |
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Inverse Square Law
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I1 /I2 = d2(squared)/d19squared)
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Density Maintenance Formula
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mAs1/ mAs2 = d1(sq) / d2(sq)
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Heat Unit Formula:
Single Phase |
HU = mA x sec x kV
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Heat Unit Formula:
3 phase 6 pulse |
HU = mA x sec x kV x 1.35
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Heat Unit Formula:
3 phase 12 pulse |
HU = mA x sec x kV x 1.41
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Anode Heel Effect
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Intensity > on cathode side.
Most effective with: -small anode angle -short SID - larger IR |
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Causes CR Gaininess
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Underexposure
Incorrect processing algorithm Not collimated properly grid cutoff |
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Window Level
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Brightness / Density
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Window Width
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Contrast
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Grid Ratio Increases
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Scatter increases & contrast resolution improves
Increase contrast Increase exposure factors(mAs) Positioning latitude decreases |
