X-Ray tube

aargueta93's version from 2015-10-07 16:38

Material of x-ray tube

Question Answer
What material is the filament in the x-ray tube made out of?thoriated tungsten
What material if the focusing cup made out of?nickle, it condenses electrons with its negative charge
What material is the stationary portion of the anode constructed of?Tungsten-rhenium alloy in copper
What material is the rotating portion of the anode constructed of?Graphite, molybdenum, tungsten rhenium alloy
What material is the rotor made of?copper cylinder cuff and molybdenum shaft, has internal silver ball bearing btwn cuff and shaft
What is the stator composed of?series of electromagnets outside the glass envelope, ( the rotar switch send current)
What is the tube housing constructed of?Lead and aluminum.


Question Answer
What is the definition of Off focus radiation?Radiation that is not produced at the focal spot on the anode
What is the filament life?6-9 hrs, or 10,000-20,000 exposures
What are the 3 Functions of the anode assembly?1. target surface for x-ray production What2. conducts high voltage from cathode back to x-ray generator circuitry 3. servers as teh primary thermal conductor
What is the purpose of Anode cooling Charts?demonstrate the calculation of time necessary for the anode to cool enough for additional exposures to be made.
What is the purpose for Tube rating charts?can help determine which techniques are safe and those that would be hazardous for tube operation.
What si the purpose for the tube housing?protects the glass tube, prevents the escape of leakage radiation(no more than 100 mR/hr at a distance of 1m)
What is the purpose of the insulating oil in the tube housing?dissipates heat, and insulates tube.

Heat Units

Question Answer
SingleHU= kVp X mA X seconds
3 phase, 6 pulseHU= kVp X mA X seconds X 1.35
3 phase, 12 pulse of higherHU= kVp X mA X seconds X 1.40

Generation Conversions

Question Answer
Single Phase to 3 phase 12 pulse or higher0.5 X mAs
single phase to 3 phase 6 pulse0.6 X mAs
3 phase 12 pulse or higher to single phase2 X mAs
3 phase 6 pulse to single phase1.6 X mAs


Question Answer
Who invented fluoroscopy?Thomas eddison in 1896
What year did roentgen discovered xrays?nov 8, 1895
Who invented the image intensifier?Russel H. Morgan in the late 1940's
What is the function of the imgae intensifier?converted the xray image into an electron beam that could be accelerated and focused for intensification. Its sole purpose was to increase the brightness of the image, dramatically reduced the mA solution required for images saving patient dose