X-rays
X-ray tube
x-ray tube cont. and radiation
x-ray beam
x-ray beam cont. and attenuation
100
How are x-rays similar to visible light?
X-rays travel at the same speed and obey the same laws as visible light.
100
What are the three components of an x-ray tube?
Cathode, anode, and vacuum tube
100
What is the electron space cloud?
When electrons are boiled off from thermionic emission and collect near the filament.
100
What is primary radiation?
Radiation confined to the portion of the x-ray beam emitted by the tube, which has not yet passed through the patient or object being studied.
100
What is remnant radiation?
Radiation that makes it through the patient and hits the IR.
200
How are x-rays different than visible light?
X-rays have a much shorter wave length and are able to penetrate materials.
200
What are the two parts of the cathode?
Heating filament and focusing cup
200
Why was the rotating anode created?
To prevent melting and allow the x-ray tube to last much longer
200
How much radiation is absorbed in the body?
80%
200
What is another name for attenuation?
partial absorption
300
Who were X-rays discovered by and on what date?
Wilhelm Conrad Roentgen on 11/8/1895.
300
What charge does the cathode carry?
Negative
300
What is Bremsstrahlung "breaking" (looksy loo) radiation?
When an electron passes the NUCLEUS and the positive attraction causes a deceleration and change of direction of the electron. This in turn causes a loss of kinetic energy, and the lost energy is emitted as an x-ray photon.
300
What is secondary radiation and what percentage does it make up of primary radiation?
Secondary radiation is the radiation the makes it out of the patient. 20%
300
Define partial absorption
reduction in x-ray intensity that occurs when x-ray beam traverses a body part
400
How is x-ray wavelength measured?
Angstroms
400
What charge does the anode carry?
Positive
400
What is characteristic radiation?
When an electron passes an orbital electron, it's repulse negative charge will eject the orbital electron out of it's orbit, leaving a vacancy in the electron shell of the atom. The atom is left with a net positive charge and will pull in another electron, usually from an outer shell to fill the vacancy. Energy is lost when an electron falls from an outer orbit down to an inner orbit, and that energy is emitted as a characteristic x-ray.
400
What are the two types of secondary radiation with their appropriate percentages?
15% is scatter radiation and 5% is remnant radiation.
400
How does subject density relate to absorption?
Soft tissues are easily penetrated, but produce a lot of secondary radiation, which can fog an image. Bone is made up of mineral matter and absorbs x-rays creating light gray densities on image. Thick body parts absorb a large number of x-rays. The denser the object, the more absorption will occur.
500
Do x-rays curve or do they travel in straight lines?
X-rays travel in straight lines and ricochet off surfaces.
500
What is thermionic emission?
The process of the cathode filament wire being heated to boil off of electrons.
500
What type of radiation occurs more often?
Characteristic radiation
500
What is scatter radiation?
Radiation that makes it through the patient, but changes directions before hitting the IR.
500
What is subject contrast?
differences in x-ray absorption occurring in an anatomical part
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