Ch.2 PPT

Question 1

The ___ is heated, and electrons are emitted.

The electrons are attracted to the ___, move rapidly towards the ___, and are ___.

Answer 1

cathode, anode, anode, decelerated

Question 2

Tungsten is a good material for the target because of 3 things:

Answer 2

1) high melting point
2) efficiently produces x-rays
3) high Z

Question 3

What % are Bremsstrahlung interactions?

Answer 3

85%

Question 4

What % are Characteristic interactions?

Answer 4

15%

Question 5

Events on cathode side when preparing the tube for exposure:

1. What happens to the filament?
2. the heat ____ ____ ____, also called ___.
3. then the electrons…
4. what does the focusing cup do?
5. what happens with the # of electrons?

Answer 5

1. filament is heated
2. boils off electrons, thermionic emission
3. electrons gather in a cloud around the filament
4. focusing cup keeps electron cloud focused together
5. # of electrons in the space cloud effect is limited (space charge effect)

Question 6

What happens on the anode side when preparing the tube for exposure?
- The ___ ___ begins to turn rapidly.

Answer 6

rotating target

Question 7

Once exposure is initiated, what happens on the cathode side?

1. High ___ charge strongly ___ electrons.
2. electrons go toward ___.

Answer 7

1. negative, repels

2. anode

Question 8

Once exposure is initiated, what happens on the anode side?

1. High ___ charge strongly ___ electrons in the tube current.
2. Electrons ___ the anode.
3. ___ and ___ are produced.

Answer 8

1. positive, attracts
2. strike
3. heat, x-rays

Question 9

Kilovoltage creates ___ ___.

Answer 9

potential difference

Question 10

Kilovoltage determines ___ of electrons in tube current.

Answer 10

speed

Question 11

Increasing electron speed will increase x-ray beam ___.

Answer 11

penetrability (quality)

Question 12

Unit to measure tube current or number of electrons flowing per unit time is called.

Answer 12

Milliamperage (mA)

Question 13

The smaller the anode angle the ___ the effective focal spot size.

Answer 13

smaller

Question 14

Aluminum filtration added to x-ray beam to absorb low-energy x-rays is beneficial because it ___.

Answer 14

reduces pt exposure

Question 15

Heat Units (HU) equation:

Answer 15

HU = mA x time x kVp x generator factor

Question 16

Generator factor:
3 phase = ?
High frequency = ?

Answer 16

1. 35

1. 40

Question 17

the positive side is the ___.

Answer 17

anode

Question 18

the negative side is the ___.

Answer 18

cathode

Question 19

How can you extend the life of the x-ray tube? (2)

Answer 19

1. Cooling down the tube

2. Warming up the tube