Chapter 10 Word Scramble

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Question	Answer
What is Filtration?	The process of eliminating undesirable low-energy x-ray photons by the insertion of absorbing materials into the primary beam
Filtration is also called __________ because it removes the low energy photons.	Hardening the beam
What is the primary reason for filtration?	Elimination of photons that would cause increased radiation dose to the patient but would not enhance the radiographic image.
At what keV does significant soft-tissue penetration occur?	between 30 and 40
Why is low energy photons insufficient energy?	Because they dont have enough energy to exit the patient and make any contribution to the image.
What is a filter?	Any material designed to selectively absorb photons from the x-ray beam.
What is the standard filtering material and what terms is it expressed in?	Aluminum...Thickness of aluminum equivalency (Al/Eq)
___________is that amount of absorbing material that will reduce the intensity of the primary beam to one-half its original value and its an indirect measure of the total filtration in the path of the x-ray beam.	Half-value layer (HVL)
What are the types of filtration?	Inherent, Added, Compound, Compensation, and Total
Filtration that is a result of the composition of the tube and housing because it is a part of these structures.	Inherent Filtration
What structures of the tube and housing contributes to inherent filtration?	thickness of the glass envelope of the tube, the dielectric oil that surrounds the tube, and the glass window of the housing.
What is the range for total inherent filtration in mm of Al/Eq	0.5-1.0mm Al/Eq
What causes an increase in inherent filtration?	pitted anode and the vaporized metal on the tube.
What is added filtration?	Any filtration that occurs outside the tube and housing and before the image receptor.
What is the collimators average filtration and where does it come from?	1.0 mm Al/Eq. Comes from the silver on the mirror situated in the beam.
What is a compound filter? What is another name for this?	Two or more materials to complement one another in their absorbing abilites. K-edge filter
What materials are used in compound filtering and how are they arranged?	Tin, copper, and aluminum. In that order with highest atomic number closest to the tube and lowest atomic number closer to the pt.
Why are compound filters arranged this way?	So that each layer absorbs the characteristic photons created by the previous layer.
Give an example of a compound filter and in what area of radiology is it used?	Thoreaus filter. Radiation therapy.
What is the purpose of compensating filters?	to add an absorber to compensated for unequal absorption with the subject, thus making the over all absorption of the primary beam more equal.
Give examples of compensating filters	Wedge filter and trough filter
What are some materials used in compensating filters?	aluminum, lead plastic trademarked ClearPb, or plastic
What could a wedge filter be used for?	Procedures on the thoracic spine, feet, and lower extremities.
What could a trough filter be used for?	to even the density differences between the mediastinum and the lungs on a chest x-ray
What is total filtration?	The sum of inherent and added filtration. (This doesnt include any compound or compensating filter that may be added later)

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