問題一覧
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concerned with providing occupational radiation protection dose to the public
Health Physics
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scientist concerned with research and operational aspects of radiation safety
Health Physicist
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Cardinal Principles of Radiation Protection KMI
- keep time of exposure as low as possible - maintain a large distance as possible between source of radiation - insert shielding material
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______: This is called when the time of exposure should be kept to a minimum ______: to reduce motion blur, one shot ______: to reduce patient & personnel exposure, moving images
> Minimize Time > Radiography > Fluoroscopy
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_____ _____ is inversely related to the distance between the source & the patient
Radiation dose
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the intensity of radiation at a location is inversely proportional to the square of its distance
Inverse Square Law
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what to do to greatly reduce the level of radiation exposure? composition (lead), protective apron 0.5 mm of ______, reduces occupational exposure to 25%
Use Shielding > Lead
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thickness of absorber necessary to reduce radiation intensity to half its original value
Half Value Layer
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thickness of absorber necessary to reduce radiation intensity to one-tenth its original value
Tenth Value Layer
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contained within protective housing, reduces leakage radiation
Protective X-ray Tube Housing
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condition of exposure, must positively indicate when x-ray tube is energized, kVp & mA indicators
Control Panel
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collimators for special examination
Cones & Diaphragm
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- They must be adjusted so that with any image receptor size in use and at all standard SIDs, - no longer required by continue to be part of the most radiographic imaging systems.
Positive Beam Limitation
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Each radiographic tube should be provided with a mechanism Purpose is to ensure proper alignment of the x-ray beam & the IR
Beam Alignment
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the output radiation intensity should be constant from one exposure to another. This is checked by making repeated radiation exposures through the same technique and observing the average variation in radiation intensity.
Reproducibility
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When adjacent mA stations are used, for example, 100 mA and 200 mA, the exposure time is adjusted for constant mAs, the output radiation intensity should remain constant. When the exposure time remain constant, causing the mAs to increase in proportion to the increase in mA, radiation intensity should be proportional to mAs. Radiation Intensity: ___/____
Linearity > mR/mAs
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_______: it is when RT may be in the exposure room during exposure, but only if protective apparel is worn ______ ______: fixed, not a long cord
Operator Shield > Exposure Control
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These are parts of _______ ____: should be assigned ____: at least 2m from x-ray tube during exposure
Mobile X-ray Imaging System > Lead Apron > Exposure Switch
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radiation from x-ray tube
Leakage Radiation
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radiation from patient
Scatter Radiation
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receives the image
Image Receptor
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in charge of quality & contrast
kVp
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in charge of quantity and density
mAs
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What do you call this? and what is the minimum? at least mm Al when above 70 kVp at least mm Al when 50-70 kVp at least mm Al when below 50 kVp
Filtration 2.5mm Al 1.5mm Al 0.5mm Al