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Radt 465
image Production
| Question | Answer |
|---|---|
| Visibility Factors are | brightness and grayscale (pg 313) |
| Geometric Factors are | spatial resolution and distortion (pg 313) |
| exposure/technical factors we use to create image | milliamperage (mA), exposure time (s), kilovoltage (kv) and SID (pg 313) |
| 4 qualities by which radiographic image is evaluated | brightness, contrast/grayscale, spatial resolution and distortion (pg 314) |
| brightness refers to | the amount of light transmitted by the display monitor (pg 314) |
| contrast | when two or more differing brightness levels are present in a radiographic image (pg 314) |
| what is the function of contrast | to make details visible (pg 314) |
| subject contrast | refers to the various body tissue densities and thickness, which results in differential absorption of the x-ray beam and signal difference within the remnant beam (pg 314) |
| milliampere seconds (mAs) | the product of milliamperes (mA) and exposure time (pg 314-315) |
| reciprocity law | any combination of mA and time that will produce a identical receptor exposure (pg 315) |
| SID | inversely proportional to receptor but has no impact on contrast (pg 315) |
| inverse square law equation | I1/I2= D2^2/D1^2 (pg 316) |
| kV | quantity/penetration (pg 317) |
| what factors have an effect on the production of scattered radiation | beam restriction, kV and thickness and density of tissues (pg 318) |
| most important way to limit the production of scattered radiation and improve contrast | limiting the size of the irradiated field though beam restriction (pg 318) |
| what does scatter radiation do to an image | adds image-degrading fog to the diagnostic image (pg 231) |
| the single most important way to reduce scattered radiation | restrict the size of the x-ray field (pg 321) |
| grid | a device interposed between the part and IR that functions to absorb a large percentage of scattered radiation before it reaches the IR (pg 321) |
| what is a grid composed of | alternating strips of lead foil and radiolucent filler material (pg 321) |
| stationary grids | simplest type and consist of alternating vertical lead strips and radiolucent interspace filler material (pg 322) |
| example of stationary grid | slip on or wafer (pg 322) |
| disadvantage of stationary grid | grid lines (pg 322) |
| moving grid | in motion during the exposure and grid lines are effectively blurred out of the image (pg 323) |
| focused grid | a grid with lead strips angled (pg 323) |
| convergence line | a imaginary line is extended up from each lead strip (pg 323) |
| angulation errors | angulation against the lead strips causes grid cutoff (pg 323) |
| off-level errors | if the planes of the x-ray tube and grid surface are not parallel, grid cut0ff will occur (pg 323) |
| off-focus errors | if the SID is below the lower limits or above the upper limits of the specified focal range, grid cutoff will occur (pg 324) |
| off-center errors | if the x-ray beam is not centered to the grid, grid cutoff will occur (pg 324) |
| examples of additive pathologies | ascites, rheumatoid arthritis, paget's disease, pneumonia, atelectasis, CHF, edematous tissue (pg 331) |
| examples of destructive pathologies | Osteoporosis, osteomalacia, pneumoperitoneum, emphysema (pg 331) |
| PSP is composed of | europium-doped barium fluorohalide coated on a storage plate (pg 368) |
| when does image fading occur | when there is a delay in reading the PSP (pg 374) |
| how long should you wait to erase an IP and its PSP storage plate that has been unused | 48 hours (pg 374) |
| what conditions can cause failure of exposure field recognition | poor or overlapping collimation, SR and metallic bodies (pg 376) |
| narrow histogram | the blacks are to the left and the whites from the right are squeezed to the center of the histogram resulting in a gray low contrast image (pg 376) |
| wide histogram | the mid-histogram gray pixels have moved laterally towards the blacks and whites, resulting in a higher contrast image (pg 376) |
| image with low brightness | the histogram pixels have shifted to the left and the histogram becomes narrow (pg 377) |
| image with high brightness | the histogram pixels have shifted to the right and the histogram becomes wider (pg 377) |
| histogram | Graphic representation of pixel value distribution (pg 377) |
| windowing | used to alter image brightness and/or contrast (pg 378) |
| change in window width | affects change in the number of gray shades (pg 378) |
| change in window level | affects change in the image brightness (pg 378) |
| shuttering | used to remove the bright unexposed areas outside of the collimated field that contribute to veil glare (pg 380) |
| DR system | are direct or indirect capture and conversion systems of x-ray imaging (pg 381) |
| bremsstrahlung is also known as | breaking radiation (pg 388) |
| bremsstrahlung radiation comprises | 70-90% of the x-ray beam (pg 388) |
| wavelength | the distance between two consecutive wave crests (389) |
| frequency | the number if cycles per second (pg 389) |
| measurement of frequency | Hertz (Hz) (pg 390) |
| mAs | affects beam quantity (pg 390 |
| kV | affects beam quality (pg 390) |
| Citation for all flashcards | Saia, D. A. (2018). Radiography prep: Program review and exam preparation. McGraw-Hill Education. |
Created by:
ktoliver1
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