Filtration Flashcards
Filtration is the process of ______ low ______ x-ray ______ by _____ of _______ into the ______.
Filtration is the process of ELIMINATING UNDESIRABLE low ENERGY x-ray PHOTONS by INSERTION of ABSORBING MATERIALS into the PRIMARY BEAM.
Filtration
Why is it called “hardening on the beam”?
Because it removes “soft” or longer wavelengths
What is the primary purpose of filtration?
To reduce patient’s radiation dose to their skin
_______ is considered the standard ______ material and all ______ units can be expressed in terms of _______ of ______ equivalency or (__/___).
ALUMINUM is considered the standard FILTERING material and all FILTRATION units can be expressed in terms of THICKNESS of ALUMINUM equivalency or (AL/Eq).
What are the types of filtration?
- Inherent filtration
- Added filtration
- Compensating filtration
Inherent filtration
- is composed of…
- the average X-ray tube provides ____-____ mm AL/Eq
- inherent filtration will…
Inherent filtration
- is composed of X-RAY TUBE AND TUBE HOUSING (GLASS ENVELOPE, DIELETRIC OIL, LEAD IN THE HOUSING)
- the average X-ray tube provides .5-1.0 mm AL/Eq
- inherent filtration will INCREASE IN THE TUBE AS THE TUBE AGES (TUNGSTEN VAPORIZATION)
The collimator averages how many mm AL/Eq? (Silver in the mirror - note: inherent filtration)
Collimator aberates 1.0 mm AL/Eq
Added Filtration
- is…
- most common added filter is….
- ^^ this filter is….
- ^^^ which can be __ -___ mm AL in _____
Added Filtration
- is ANY FILTRATION LOCATED BETWEEN X-RAY TUBE AND PATIENT
- most common added filter is ALUMINUM SHEET
- ^^ this filter is A THIN SHEET OF ALUMINUM
- ^^^ which can be .5 -3 mm AL in THICKNESS
Total filtration is the sum of…
Inherent and added filtration
The National Council on Radiation Protection (NCRP) states the minimum total filtration must be:
- equiptment below 50 kVP =
- equiptment that is 50-70 kVp =
- equiptment > 70 kVp =
The National Council on Radiation Protection (NCRP) states the minimum total filtration must be:
- equiptment below 50 kVP = .5 mm AL/Eq
- equiptment that is 50-70 kVp = 1.5 mm AL/Eq
- equiptment > 70 kVp = 2.5 mm AL/Eq
Compensation Filtration
- designed to…
- makes…
- common filters are…
Compensation Filtration
- designed to SOLVE A PROBLEM OF UNEQUAL DENSITIES IN PATIENTS
- makes OVERALL DENSITIES ON THE RADIOGRAPHIC FILM MORE EQUAL
- common filters are WEDGE AND TROUGH
- Wedge filters are common for…
- Trough filters are common for…
- Single trough are for…
- Wedge filters are common for FEMURS, THORACIC-LUMBAR SPINE, FEET
- Trough filters are common for CHEST X-RAYS
- Single trough are for ONE SIDE ONLY
Compound Filter uses…
ex)
- ______ will used filters made of ___ or more _____ (_______, ______, and _____ are called a K-edge filter)
Compound Filter uses 2 OR MORE MATERIALS THAT COMPLEMENT ONE ANOTHER
ex) THOREAUS FILTER
* RADIATION THERAPY will used filters made of 2 or more METALS (COPPER, ALUMINUM, and TIN are called a K-edge filter)
Effects on Radiation Output
- As ______ increases, so does the ______ of _______ is ______. (More _____ wavelengths are _____)
- In order to maintain _______ of the radiographic film, you must _____ the ________. (kVP or ___)
Effects on Radiation Output
- As FILTRATION increases, so does the AMOUNT of PRIMARY BEAM is REMOVED. (More SHORTER wavelengths are ABSORBED)
- In order to maintain SAME DENSITY of the radiographic film, you must INCREASE the TECHNICAL FACTORS. (kVP or mAs)
- Filtration is measured in…
- ____ is the amount of _______ that will ____ the ____ of the ____ to _____ of it’s ____ value
- Filtration is measured in HALF VALUE LAYERS
- HVL is the amount of ABSORBING MATERIAL that will REDUCE the INTENSITY of the PRIMARY BEAM to ONE-HALF of it’s ORIGINAL value
