Chapter 5 Exam

Question 1

Anode side is the _______ side of the tube

Answer 1

positive

Question 2

Anode (positive side of the tube) made of _______ because it has a very high _____ _____ and a high ______ ______ (__)

Answer 2

tungsten, melting point, atomic number (74)

Question 3

anode serves as:

Answer 3

A target for electron interaction to produce x rays.
As an electrical and thermal conductor

Question 4

what does the x-ray tube guard against?

Answer 4

leakage radiation

Question 5

photons inside the x-ray tube housing leave through the ______ and are the ______ _____

Answer 5

window, primary beam

Question 6

the x-ray tube housing protects against:

Answer 6

electric shock

Question 7

inside the housing, the x-ray tube is surrounded by ____ (______ ____) - possible cooling fan

Answer 7

oil (dissipate housing)

Question 8

the main purpose of the x-ray tube is to maintain a ______ within the tube to prevent _______ ______

Answer 8

vacuum, electrical arcing

Question 9

__% of the electrons that hit the anode target are turned into heat, and __% are converted to x-ray

Answer 9

99%, 1%

Question 10

what is the advantage of a rotating anode?

Answer 10

spreads the heat produced during x-ray production over a larger surface area

Question 11

anode is made of:

Answer 11

copper (shaft)
molybdenum (disc base and core)
tungsten (outside)

Question 12

the anode is rotates using an:

Answer 12

induction motor

Question 13

what are the two parts of the induction motor?

Answer 13

stator & rotor

Question 14

what is the stator made up of?

Answer 14

electromagnets arranged in pairs around the rotor

Question 15

what is the rotor made up of?

Answer 15

iron core (iron bars embedded in the copper shaft) surrounded by coils

Question 16

what happens when you press the exposure button half way down?

Answer 16

Stator windings energized
sequentially & rotor accelerated to designated rpm

Question 17

what happens when you press the exposure button all the way down?

Answer 17

Filament is Heated-Electrons cloud is forming
“BEEP” – kVp is applied, electrons strike the anode, photons are produced

Question 18

When the angle of the target face is less than __ degrees, the effective focal spot will be smaller than the actual

Answer 18

45

Question 19

The target angles are __ to __ degrees for a general-purpose tube (__ degrees is the most common)

Answer 19

7 to 18, 12

Question 20

The smaller the anode angle, the ______ the effective focal spot will be while maintaining a large actual focal spot area

Answer 20

smaller

Question 21

The _____ the effective focal spot, the sharper the image will be

Answer 21

smaller

Question 22

Smaller anode angle = _____ heel effect

Answer 22

larger

Question 23

Effective focal spot size is where:

Answer 23

the x-rays come out

Question 24

Anode heel effect:

Answer 24

intensity is more toward the cathode

Question 25

Cathode side is the ______ side of the tube

Answer 25

negative

Question 26

Cathode provides: and is made up of:

Answer 26

The source of electrons needed for x-ray production The filaments and the focusing cup

Question 27

Dual focus tubes have ___ filaments

Answer 27

2

Question 28

Each filament is a coil of wire made of:

Answer 28

tungsten with 1-2% of thorium

Question 29

Focusing cup is made of _____ and surrounds the ________ back and sides, leaving the front open and facing the anode target

Answer 29

nickel, filaments

Question 30

The focusing cup receives a strong ______ charge from the secondary circuit that forces the _______ together into a cloud as they are boiled off the _______ through electrostatic repulsion

Answer 30

negative, electrons, filament

Question 31

Inside the x-ray tube, the induction motor turns the anode at approximately ____ rpm

Answer 31

3400

Question 32

Once the space charge reaches a size commensurate with the current used, it becomes difficult for additional electrons to be emitted

Answer 32

space-charge effect

Question 33

3 things needed to produce x-rays

Answer 33

A large potential difference to give kinetic energy (provided by kVp) A vehicle in which kinetic energy can ride (provided by mAs) A place for interaction (the target of the anode)

Question 34

The overall density of our image is the ____

Answer 34

black

Question 35

thee difference between the whites and blacks is:

Answer 35

contrast

Question 36

A measure of the amount of heat stored in a particular device

Answer 36

heat units

Question 37

how to calculate heat units

Answer 37

kVp x mA x s x c

Question 38

single phase formula:

Answer 38

mA x time x kVp

Question 39

three phase formula:

Answer 39

mA x time x kVp x 1.35

Question 40

high frequency formula:

Answer 40

mA x time x kVp x 1.40

Question 41

Which if the following reduces leakage radiation to required standards?

Answer 41

Protective housing

Question 42

Which component of the x-ray tube us responsible for concentrating the electron cloud?

Answer 42

Focusing cup

Question 43

The x-ray tube is part of the:

Answer 43

X-ray circuit secondary

Question 44

A technique of 80 kV, 400 mA, 0.8 seconds is to be used on a 3-phase, 12-pulse machine. How many heat units are produced with a single exposure?

Answer 44

36,096

Question 45

The intensity of the x-ray beam is less: | which side?

Answer 45

On the anode side

Question 46

Causes of tube failure are most often related to which of the following?

Answer 46

Thermal characteristics

Question 47

What metal is added to the filament to increase thermionic emission and extend tube life?

Answer 47

Thorium

Question 48

A small anode target angle: | results in?

Answer 48

Results in an increase in anode heel effect

Question 49

A dual focus tube refers to a tube with:

Answer 49

Two filaments

Question 50

The purpose of the line focus principle is to create which of the following?

Answer 50

Large actual and small effective focal spot size

Question 51

A technique of 50 kV, 100 mA, 0.1 seconds is to be used on a 3-phase, 6-pulse machine. How many heat units are produced with a single exposure?

Answer 51

675