-
Energy carried by waves or a stream of particles:
radation
-
Method of transporting energy through space. X-ray:
Electromagnetic radiation
-
A form of electromagnetic radiation similar to visible light but of shorter wavelength:
X-ray
-
A number of x-rays traveling together through space at a rapid speed:
X-ray beam
-
Physical properties of X-rays
_______ is variable and is related to the energy of the radiation.
Wavelength
-
The travel of an X-ray is:
Straight line
-
X-rays are able to penetrate materials that absorb or reflect_____.
Visible light
-
Certain substances will _______ after absorbing electromagnetic radiation
Fluoresce
-
X-rays produce an invisible image on photographic film that can be made visible by_______.
Processing film
-
X-rays can cause ________ in living tissue.
Biological changes
-
Discovery of the x-ray:
>Who?
>Where?
>When?
- > Wilhelm Roentgen
- > Wurzburg, Germany
- > 1895
-
X-rays were originally called:
Roentgen rays
-
X-rays can cause 2 different biological changes to living tissue:
>________ cells in the body
>________ reproductive cells
-
__________, the ease by which you see a radiograph. Depends on density, contrast, and geometric factors.
Radiographic quality
-
The degree of blackness of a radiograph. It is influenced by the quantity and quality of the x-ray beam as well as type and ______ of the tissue. What is it?
Radiographic density
-
Factors affecting density:
- > total number of x-rays
- > penetrating power of the x-ray
- > developing time
- > developer temperature
-
The visible difference between adjacent radiographic densities. Two categories:
>
>
- Radiographic contrast
- Subject contrast
-
Radiographic contrast is influenced by:
>
>
>
>
>
- > subject contrast
- > kVp level
- > scatter radiation
- > film type
- > film fog
-
The density difference between adjacent anatomic structures. There should be varying shades of black, gray and white.
subject contrast
-
The mA's will affect contrast only when _______ or ________ mA's is used. When a correct mA's is used the contrast is dependent on the _____ setting.
- > excessive, insufficient
- > kVp
-
kVp can affect both ______ and ______. If insufficient kVp is used the film will have an overall _______ appearance and subject contrast is _____. If excessive kVp is used ________ will be evident; film being too dark or "burned".
- >contrast, density
- >gray, low
- >scatter radiation
-
Non-image forming radiation that is a result of the primary beam not being focused on the patient or being delivered at to high a rate.
Scatter radiation
-
To prevent scatter radiation you must use:
>
>
>
- >appropriate kVp>appropriately collimate
- >utilize a grid in tissue densities over 10cm
-
A device placed between the patient and the film that is designed to absorb scatter radiation.
Grids
-
Composed of alternating lead strips and spacer material, may be as many as _____ lead strips. It is designed to allow the majority of the primary beam to reach the patient while absorbing unused radiation.
-
Types of grids:
>
>
>
>
- > linear grid
- > crossed grid
- > focused grid
- > unfocused grid
-
Device that is built into the table to hold the grid and allows the grid to move across the beam. This will eliminate line and helps to absorb the radiation.
Potter-bucky diaphragm
-
Two examples of geometric distortion:
>
>
- >elongation
- >foreshortening
-
A rigid film holder designed to hold the film and intensifying screens in close contact.
Cassette
-
Cassettes can be made from:
>
>
>
the back is normally made of _____ to absorb scatter.
- >polycarbonate
- >aluminum
- >magnesium, and carbon fiber
- >lead
-
Some cassettes have a small rectangular area in one corner called a _______. It's purpose is to not allow exposure to that area for imprinting purposes.
Lead blocker
-
Cassette sizes vary, but the ones we use at Tomball are:
-
Cassettes can be damaged in two ways:
>
>
- >dropping the cassette
- >spilling fluid onto cassette
-
_____ are luminescent phosphor crystals bound together and mounted on a plastic base.
Intensifying screens
-
The purpose of intensifying screens is to reduce the amount of radiation exposure needed to produce the __________. The use of screens results in ________. ___% should be produced by the intensifying screen.
- >Latent image
- >lower mA usage
- >95%
-
Screen layers within a cassette:
>
>
>
>
- >support or base
- >reflective layer
- >phosphor crystal layer
- >protective coating
-
Screen types:
>______ developed in 1896 by Thomas Edison. Blue light sensitive
>______ developed in 1972. Green light sensitive
- >calcium tungsten
- >rare earth
-
Screen speed:
>slow -
>medium -
>fast -
- >high definition, maximum detail
- >most commonly used in veterinary medicine
- >reduce exposure times, thick tissue densities
-
Purpose is to create a permanent record
film
-
Film composition:
>
>
>
>
- >base
- >emulsion
- >silver halide
- >supercoat
-
Film types:
>
>
- >screen film
- >non-screen film
-
Film speed: (most widely used)
>
>
>
- >slow
- >medium - widely used
- >fast
-
Proper film care:
>
>
>
>
- >store vertically
- >low humidity
- >room temperature
- >awareness of expiration date
-
Before we had imprinter cards we had:
>
>
- > lead tape
- > lead markers
-
Boundaries for a thoracic x-ray:
>______ and ______
> scapular-humoral joint and thoracic vertebrae
-
When developing, the rule of thumb concerning the temperature of the developer:
>
>warmer the water the lesser the time it takes to develop
-
Problems we can have with the x-ray and how the x-ray is made:
>
>
>
- >filament lifespan: wears out, fails
- >bearing damage on rotating anode
- >damaged glass envelope - fractured
-
Measures the patient area. Always read bottom of bar in ____.
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