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RADT 456
Image Acquisition and Evaluation
Question | Answer |
---|---|
True or False Pixel size is inversely related to resolution. | True pg. 232 |
True or False When filtration is added to the x-ray beam, the maximum energy of the beam is increased. | False pg. 233 |
Which grid material resists moisture, provides a smoother appearance, and has less visible grid lines? | Aluminum pg. 233 |
Are scatter radiation and field size directly or indirectly related? | directly pg. 234 |
How many inches do you increase SID to compensate for one inch of OID? | 7 inches pg. 234 |
What is the process called when the PSP plate is scanned in the CR reader and releases a violet light? | photostimulated luminescence pg. 235 |
A change in window width, changes what on the image? | Contrast or the number of grays pg. 235 |
Daily QA ensures that fog levels do not exceed the upper limit of how much density? | 0.2 density pg. 236 |
What is the term used to describe how well the phosphors detect and interact with the x-ray photons? | quantum detection efficiency pg. 238 |
As matrix size is increased spatial resolution goes up or down? | spatial resolution goes up pg. 238 |
What are the three factors that have an effect on the production of scatter radiation? | kV, beam restriction, and thickness/volume of tissues pg. 239 |
True or False Contrast is related to mAs? | False pg. 239 |
What is the matrix size of a typical CT image? | 512 x 512 pg. 240 |
How long does it take for image fading to occur after PSPs has been exposed? | several hours pg. 240 |
If an exposure was taken using no grid at 2 mAs, what will the mAs need to be to produce the same density with a 5:1 grid? | 4 mAs pg 242 |
What is the process called when electrons are released by the cathode filament? | thermionic emission pg 242 |
What are the two types of shape distortion? | elongation and foreshortening pg 243 |
True or False Congestive heart failure is an example of a destructive pathology. | False pg. 245 |
When changing from single phase to three phase, 12 pulse equipment how much of the original mAs is needed to produce the same density? | one half pg. 246 |
What are the four steps film goes through during automatic processing? | developer, fixer, wash, dryer pg. 247 |
What is the unit of measurement for frequency? | hertz (Hz) pg. 248 |
What is influenced by rectification, kV, and total filtration? | HVL pg. 251 |
What layer is under the phosphor "active" layer in an IP? | electroconductive layer pg. 252 |
What system is used for scheduling and patient registration, billing, and workflow management? | RIS pg. 254 |
As grid ratio increases, the contrast scale gets longer of shorter? | shorter pg. 255 |
True or False There are fewer photons at the anode end of the x-ray tube than the cathode end? | True pg. 258 |
About how many light photons are produced for each x-ray photon absorbed by cesium iodide? | 5,000 light photons pg. 260 |
Change in window width or window level changes the number of gray shades on an image? | window width pg. 261 |
In which x-ray interaction does a relatively low energy photon uses all its energy to eject an inner shell electron? | photoelectric effect pg. 263 |
The spatial resolution of direct digital systems is fixed and related to what? | DEL and TFT size pg. 264 |