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18 Cards in this Set
- Front
- Back
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What does immobilization reduce?
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Motion
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What is the purpose of beam restriction?
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Reduces scatter production
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What are the different types of beam restriction?
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Aperture diaphragm
Cone Collimator Positive Beam Limitation - auto collimation |
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What is the purpose of filtration?
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Reduce low energy x-rays that would be absorbed by the patient and not used to create an image
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What are the different types of filtration?
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Inherent - in the tube
Added - added outside the tube Total - inherent + added (should be 2.5 mm Al equivalent) |
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What are the different types of shielding?
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Gonadal
apron glove vest and skirt shadow shields |
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What is the importance of shielding?
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To absorb radiation not needed to produce the image, and prevent absorption by the patient. Especially in areas of high radiosensitivity
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What technical factors directly effect patient dose?
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KVp and mAs
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What factors effect dose in film/screen combinations?
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Intensifying screens used
Film speed |
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How does film screen speed effect the dose?
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Higher speed = less radiation needed
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How is positioning important in dose reduction?
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Proper positioning eliminates repeat exposure, and allows for proper techniques to be used to obtain diagnostic quality
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What is a main rule of positioning projections in a series?
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Always two projections 90 degrees from each other - 1 view is no view
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What is the purpose of a grid?
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Eliminate scatter from reaching the IR
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What is the role of grids in radiation protection?
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Grids increase technical factors needed to obtain the image - decrease the risk of absorbed radiation
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What is the general rule of pregnancy in radiology?
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Ten day rule
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How does the image intensifier in fluoroscopy effect the image?
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7,000 - 20,000 X brighter image - less radiation needed
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What are some ways to reduce patient exposure in radiation therapy?
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Use pulsed - decreases 90% of exposure than non-pulsed
shield if applicable have all equipment ready to reduce exposure |
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What are the SID requirements in fluoroscopy?
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15 in stationary
12 in portable |
