Ch.16 Generators And Filtration

Question 0

Which part of the beam spectrum changed when generator power increases?

Answer 0

The average energy increases

There is and increase of amplitude and slight shift to the right

Question 1

As the power of the generator increase what happens to the quantity and quality of the electrical current across the tube?

Answer 1

They increase

Question 2

What are the set percentages of kVp for each type of generator?

Answer 2

Single phase 33%
3 phase 6pulse 91%
3 phase 12 pulse 97%
High frequency 99%

Question 3

T/F: You can cut mAs in half when you go from low energy generator to high?

Answer 3

True

Question 4

With a higher percent kVp what happens to the penetration of the beam?

Answer 4

It increases

Question 5

What is the purpose of filtration of the primary X-ray beam?

Answer 5

To eliminate unnecessary patient exposure

Question 6

What would happen without filtration?

Answer 6

There would be millions of very low energy photos that would have no chance of penetrating the patient to reach the IR and be useful

Question 7

What are the 3 types of filtration?

Answer 7

• Added filtration
• Inherent filtration
• Compensating filtration

Question 8

What is added filtration?

Answer 8

Thin slabs of aluminum installed between the X-ray tube and the collimator or in a slot in the upper portion of the collimator

Question 9

What is inherent filtration?

Answer 9

Components of the X-ray tube and it’s housing such as the glass tube,oil, and beryllium window

Question 10

What type of filtration does the beryllium window provide?

Answer 10

Preliminary filtration of very low energy photons

Question 11

All X-ray machines capable of 70kvp or higher must have a minimum filtration of what?

Answer 11

2.5mm

Usually 1.5 is inherent and 1mm needs to be added

Question 12

Describe half value layer.

Answer 12

The thickness of absorbing material needed to reduce the X-ray intensity to half it’s original value.

Question 13

How does half value layer work?

Answer 13

• Increasing kVp is and increase in beam quality
• An increase in filtration is an increase in beam quality
• An increase on filtration is an increase in half value layer

Question 14

Since quality is the same and penetration then HVL actually measures the ____ of the X-ray beam

Answer 14

Penetrability

Question 15

Penetration is the ____ (opposite, same) of/as radiation absorption

Answer 15

Opposite

Question 16

Hardening of the X-ray beam means ____(greater,lesser) beam penetration. Lower or higher patient dose?

Answer 16

Greater, lesser

- so softening the beam means less penetration and more absorbed dose and higher patient exposure

Question 17

What is a compensating filter?

Answer 17

Used to get a more uniform density of unusual shaped body parts. Such as the foot.

Question 18

Which part of the X-ray beam does the compensating filter even out?

Answer 18

Remnant beam