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Ch. 10- Filtration

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kkaitlyn96's version from 2017-03-08 00:09

Section 1

Question Answer
What does filtration doeliminate low energy photons from the beam
what do the low energy photons doadd patient dose
Filtration is also known as hardening the beam
When the beam is hardened the energy (increases or decreases)increases
What photons are being eliminated with filtration?photons that create scatter
What is the primary purpose of filtrationto reduce patient dose
memorize

Section 2

Question Answer
When kVp increases, exposure _________increases
When filtration increases, exposure _________decreases
Photons with higher energy with attenuate less or more less
Photon energy and attenuation have what kind of relationship?indirect
What is the standard material used for filtration?Aluminum
Why is this material used for filtration?high atomic number, it absorbs more, is lighter than lead
memorize

Section 3

Question Answer
What is the half value layer?amount of absorbing material needed to reduce the primary beam by one half
What is the half value layer expressed in?Al/Eq
What relationship does the half value layer have to the average energy of the beam?direct
As kvp increases, the half value layer _________increases
What does the half value layer measure?filtration
At 70kVp what is the avg HVL?5cm
As HVL increases, energy _________increases
memorize

Section 4

Question Answer
Where does Inherent filtration come from?filtration in the design of the x ray tube
What does inherent filtration include?glass envelope (most), oil, window
Inherent filtration avg in Al/Eq .5-1.0mm - becomes greater with age
Where does added filtration come from?between the IR and the tube
What does added filtration include?collimation, compound, compensation
memorize

Section 5

Question Answer
Where does most of the filtration come from in collimators?the silver on the mirror
What is the avg Al/Eq for Collimators?1.0mm Al/Eq
What is a compound filter and where is it used?It is when 2 or more materials are used; radiation therapy
What is a compound filter also known as?K edge filter
How are the materials placed in a compound filter?Highest atomic number closets to tube, lowest atomic number by patient
When is a compensation filter used?When there are unequal densities
What are the two types of compensation filters?Wedge and trough
Wedge filters are used for _________ while, Trough filters are used for ___thoracic spine/ extremities, chest
memorize

Section 6

Question Answer
What is total filtration?equal to the sum of inherent and added filtration
Federal law requires that _________ mm Al/Eq is used at 70kVp or higher2.5mm
increase filtration, _________ xray photonsdecrease
increase kVp, _________ energyincrease
Increase filtration, _________ energyincrease
increase kVp, __HVLincrease
Increase filtration, __HVLincrease
memorize

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