Ch. 10 Filtration (Exp II) Flashcards
Filtration is the process of eliminating undesirable ____ by the insertion of absorbing materials into the primary beam.
Low-energy x-ray photons
Filtration permits the radiographer to ___ the photo emission spectrum into a more useful beam.
Narrow
Beam filtration does what to patient dose?
It decreases patient dose.
Beam filtration affects patient dose by…
Removing low-energy photons
In general, low-energy x-ray photons…
Are absorbed by the patient.
What is considered filter media as the beam traverses toward the patient?
- Glass
- Dielectric oil
- Aluminum
the most common diagnostic x-ray filter material is…
Aluminum
All filtration cann be expressed in terms of the thickness of…
Al/Eq
the amount of material that will reduce the intensity of the primary beam to one-half its original value is the…
Half-value layer
The half-value layer is typically expressed in…
Al/Eq
If the half-value layer of the diagnostic radiographic equipment is too low, it may be corrected by…
Increasing the primary beam filtration
What is affected by half-layer value?
Patient skin exposure
What term describes filtration that is part of the x-ray tube, and the tube housing?
Inherent
How many half-value layers must be added to the primary beam to reduce its intensity to less than 20 percent o its original value?
3
Which of the following filtrations would result in the lowest entrance skin exposure to the patient?
a. 1.0 Al/Eq
b. 1.0 Pb/Eq
c. 0.5 Al/Eq
d. 0.5 Pb/Eq
a. 1.0 Al/Eq
What term best describes the filtration that occurs as the primary beam passes through the glass window of the x-ray tube?
Inherent
Most of the inherent filtration of a typical x-ray equipment comes from the…
Window of the glass envelope
The collimator device is considered part of the ____ filtration.
Added
A Thoraeus filter combines all of the following materials EXCEPT:
a. Silver
b. Copper
c. Tin
d. Aluminum
a. Silver
The problem of unequal subject radiographic density is solved by a…
Compensation filter
What compensating filter is used most commonly in radiography of the femur?
Wedge
How is a wedge filter placed?
With the thickest portion of the wedge filter placed over the less dense part of the patient.
Total beam filtration is equal to the sum of ____ filtration.
Inherent and added
When filtration is ____, technical factors must be ____ to maintain the same density.
Increased; increased
For mammography tubes, ______ is inserted into the window of the tube.
Beryllium
All of the following are true of k-edge filters EXCEPT:
a. They are also called compound filters
b. Copper and aluminum are the materials of choice
c. They rely on photoelectric interactions and the production of characteristic radiation
d. The x-ray beam traverses aluminum first, followed by the copper layer
d. The x-ray beam traverses aluminum first, followed by the copper layer
For an x-ray beam operated at 80 kVp,
The beam is harder than a 60 kVp beam
For an x-ray beam operated at 90 kVp, the required minimum filtration must be…
1.0 mm Al/Eq inherent plus 1.5 mm Al/Eq added
A compensating wedge filter would be appropriate for…
AP food radiography
When comparing two x-ray beams, one at 60 kVp and another at 85 kVp,
a. Adding aluminum to the 60 kVp beam greatly reduces the skin dose to the patient
b. The 85 kVp beam will offer a lower entrance skin exposure
c. Adding 0.5 mm of aluminum to the 85 kVp beam will require no additional mAs in order to maintain beam intensity
d. All of the above
d. All of the above
