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Definition
Rails mount to the ceiling.
Tube moves longitudinally or horizontally. |
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| mounted at floor, not as stable as floor-to-ceiling, whole arm can tip |
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| floor-to-ceiling support system |
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Definition
| single column with rollers, attached to both floor and ceiling |
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Definition
surrounds x-ray tube, lead lined, prevents shock
-- designed to keep leakage to less than 100 mR/hr at 1m |
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| filled with air molecules causing exit production to fail = tube failure |
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Definition
negative side of x-ray tube
-- two parts: filament & focusing cup |
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Definition
- (-) charged
-focuses electron beam towards the anode
-composed of nickel |
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Definition
coil of wire
--2 mm diameter and 1 to 2 cm long |
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Thermionic emission
-electron cloud forms around the filament
-causes saturation |
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| -(.1-1mm) -for smaller body part -for >300 mA -better spatial resolution |
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Definition
--larger body part
--when a lot of x-rays are required
-- .4 to 2 mm |
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Definition
(+) of x-ray tube
-two types: stationery and rotating |
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| -- used in dental units/older portables where high tube current is not required |
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Definition
general-purpose x-ray tubes
-- a lot of heat and short period of time
-- longer tube life
-- larger area
--rotates at 3400 RPMs |
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Definition
-- electrical conductor
-- mechanical support
--thermal conductor |
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Definition
| -- copper, molybdenum, graphite |
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Definition
| -- stationary -- tungsten in copper anode -- rotating-- tungsten in molybdenum disc -- mammography --molybdenum or rhodium target |
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Definition
-- High Z# (74)
-- thermal conductor
-- high melting point (3400 Celsius) |
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Definition
2 Parts:
1)Stator-stationary. Outside envelope consists of electromagnetics equally spaced around the tube.
2)Rotor -- rotates anode. Inside envelope, made of copper |
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Definition
| effective focal spot is smaller than actual focal spot |
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Definition
-- x-ray intensity on cathode side higher than anode side (distortion gr on cathode)
--smaller anode angle, smaller heel effect |
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Definition
-- electrons bounce focal tract and interact with different parts of the anode, producing off focus x-ray
-has same result as scatter radiation
-to min exp-use diaphragm |
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Definition
-- melting or pitting of anode
-- long exposure timers
-- filament vaporization |
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Definition
-- single exposure to cold anode could cause cracking
--to avoid: after 45 minutes, anode has to be heated again (warm up of 3 exposures, 3 seconds apart @ 200 mA, 1s @ 80 kVp) |
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| point of intersection above exposure line=safe, below=unsafe |
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Definition
1 phase= kVp x mA x s
3 phase,6p= kVp x mA x s x 1.35
3 phase, 12p= kVp x mA x s x 1.41 |
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