Radiology - Veterinary
Terms
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copy deck
- Caliper
- a device used to measure the thickness of anatomic parts
- Contrast
- the measureable distance bt 2 adjacent densities
- Density
- degree of blackness on radiograph
- Exposure time
- period of time during which xrays are permitted to leave xray tube
- Inverse Square Law
- intensity of the radiation varies inversely as the square of distance from source decreases
- Kilovoltage
- related to thousands of volts of electrical potential bt cathode and anode
- Kinetic energy
- energy related to motion
- mA's
- number of xrays produced over given period
- Milliampere
- one thousandth of an ampere
- Sante's Rule
- a method of estimating kilovoltage in relation to area thickness
- Thermionic emission
- process of releasing electrons from their atomic orbits by heat
- Backscatter
- scattering or reflecting radiation in the opposite direction from that which was intended
- crossed grid
- 2 parallel or 2 focsed grids that are set at right angles
- elongation
- distortion of anatomical structures so that image appears longer
- focused grid
- a grid with a parallel center lead strip and inclined strips on either side
- foreshortening
- distortion of anatomic structures when image appears shorter than actual size
- geometric distortion
- variation in normal size or shape
- geometric unsharpness
-
atributed to
result of large focal spot or decreased SID
motion
sedation may be needed
screens and films - grid
- deive made of lead strips embedded in spacing material placed bt patient and film, designed to absorb non-image forming radiation
- grid cutoff
- progressive decrease in transmitted xray
- grid efficiency
- ability of grid to absorb non-image forming radiation
- grid factor
- the amt of exposure needs to be increased to compensate for grids absorption
- grid focus
- the distance bt the source of an xray and the grid in which the grid is effective without grid cutoff
- grid ratio
- relation bt height of lead strips to the distance bt them
- linear grid
- grid in which lead strips are parallel
- magnification
- distortion of anatomic structures when inage appears larger then actual size
- Potter-Bucky Diaphragm
- moves grid across the xray
- pseudofocused grid
- grid with parallel lead strips that are progressively reduced in height toward the edge of the grid
- radiographic contrast
- density difference bt two adjacent areas
- radiographic density
- degree of blackness
- radiographic detail
- definition of edge of atomic structure
- radiogrpahic quality
- the ease in which details are perceived
- scatter radiation
- non0image forming radiation scattered in all directions
- subject contrast
- difference bt density and mass of two adjacent anatomic structures
- unfocused grid
- grid with leas strips that are parallel and are at right angles to film
- detail and defintion - four things used to describe image
-
sharpness
clarity
distinctness
perceptability - radiographic quality depends on these three things
-
radiogrpahic density
radiogrpahic contrast
geometric factors that effect detail - density is influenced by what four things?
-
quantity of beam
quality of beam
type of tissue being radiographed
thickness of tissue being radiographed - greater radiogrpahic density may be produced by increasing
-
total # of xrays reaching film (mAs)
increased penetrating power of xrays (kVp)
increased developing time
temp of developer - radiographic contrast is influenced by what 5 things?
-
subject contrast
kVp level
scatter radiation
film type used
film fogging