The Xray Tube Part 1

Question 1

Component of Crookes tube

Answer 1

Cathode
Aluminum cross and anode
Fluorescent image
Dark shadow

Question 2

What tube did Roentgen used?

Answer 2

Crookes-Hittorf tube

Question 3

No shielding =

Answer 3

X-rays emitted in all directions

Question 4

A major advancement in tube design

Answer 4

Coolidge hot cathode tube

Question 5

Two major hazards in early radiography

Answer 5

Excessive radiation exposure

Electric shock

Question 6

Component in X-ray imaging system rarely seen by RT

Answer 6

X-ray tube

Question 7

Contained in a protective housing

Answer 7

X-ray tube

Question 8

Modern X-ray tube, Coolidge tube are

Answer 8

Vacuum tube

Question 9

Size of X-ray tube

Answer 9

30-50 cm long

20 cm diameter

Question 10

Two electrodes are called

Answer 10

Diode

Question 11

Self rectification highest limits

Answer 11

30mA at 90kV

Question 12

Overstepping the bounds can cause

Answer 12

Temperature rise in the anode target (thermionic emission)

Question 13

External structures of X-ray tube

Answer 13

Support system
Protective housing
Glass or Metal enclosure

Question 14

Internal structures

Answer 14

Anode

Cathode

Question 15

Three methods of support system

Answer 15

Ceiling support system
Floor to ceiling support system
C-arm support system

Question 16

Most frequently used support system

Answer 16

Ceiling support system

Question 17

Have two perpendicular sets of ceiling mounted railings

Answer 17

Ceiling support system

Question 18

Ceiling support system allows

Answer 18

Longitudinal and transverse travel

Question 19

Floor to ceiling has

Answer 19

Single column with rollers at each end

Question 20

Ceiling mounted and very flexible X-ray tube positioning

Answer 20

C-arm support system

Question 21

Protective housing is made of

Answer 21

Lead lined metal

Question 22

Generated isotropically and in all directions

Answer 22

X-ray photons

Question 23

Limit the beam to window

Answer 23

Housing

Question 24

Functions of housing

Answer 24

Controls leakage and scatter radiation
Isolates high voltages
Means to cool the tube

Question 25

Any photons that escape from the housing

Answer 25

Leakage radiation

Question 26

Other functions of housing

Answer 26

Mechanical support | Protection from damage

Question 27

Uses of oil

Answer 27

More insulation | Thermal cushion

Question 28

Housing is designed with

Answer 28

High voltage receptacles (avoid electric shock)

Question 29

Don'ts in handling the tube

Answer 29

Never hold the tube during exposure | Never use the cables as handles

Question 30

Glass enclosure is made of

Answer 30

Pyrex glass

Question 31

Maintains vacuum inside the tube

Answer 31

Enclosure

Question 32

Is 5cm2 with thin section glass

Answer 32

Window

Question 33

Functions of vacuum

Answer 33

More efficient production of X-ray | Longer tube life

Question 34

With the presence of air

Answer 34

Electron flow is reduced Fewer X-rays produce More heat generated

Question 35

Incorporated with metal

Answer 35

Metal enclosure

Question 36

Maintain constant electric potential

Answer 36

Metal enclosure

Question 37

High capacity X-ray tubes uses

Answer 37

Metal enclosures

Question 38

Negative side of the tube

Answer 38

Cathode

Question 39

Coil of wire

Answer 39

Filament

Question 40

Size of the filament

Answer 40

2mm diameter | 1 to 2 cm long

Question 41

Emits electrons when it is heated

Answer 41

Filament

Question 42

Filament is made of

Answer 42

Thoriated tungsten

Question 43

Provide higher thermionic emission

Answer 43

Tungsten

Question 44

Melting point of tungsten

Answer 44

3410 C

Question 45

1% to 2% thorium

Answer 45

Enhances efficiency of thermionic emission | Prolong tube life

Question 46

Two filaments | Have greater variety of exposure

Answer 46

Dual focus filament

Question 47

Rotating anode tube have

Answer 47

2 filaments

Question 48

Lower mA station

Answer 48

300 mA or less

Question 49

Most common cause of tube failure

Answer 49

Tungsten vaporization

Question 50

A shallow depression

Answer 50

Focusing cup

Question 51

House the filament

Answer 51

Focusing cup

Question 52

Metal shroud that surrounds the filament

Answer 52

Focusing cup

Question 53

Charge of Focusing cup

Answer 53

Negative

Question 54

Effectiveness of Focusing cup

Answer 54

Size and shape Charge Filament size and shape Position of Filament in the focusing cup

Question 55

Adjusted by controlling the filament current

Answer 55

Tube current

Question 56

Emission of electrons from a heated surface

Answer 56

Thermionic emission

Question 57

Thermionic emission is also known as

Answer 57

Thermal electron emission

Question 58

Process by which charge carriers move over a surface by induction of heat

Answer 58

Thermionic Emission

Question 59

Formation of electron cloud near the filament

Answer 59

Space charge

Question 60

Electrons build up in the area of the filament

Answer 60

Space charge effect

Question 61

Electrons are difficult to emit by the filament because of

Answer 61

Electrostatic repulsion

Question 62

Space charge limited

Answer 62

Thermionic emission at low kVp at high mA

Question 63

As kVp increases, greater percentage of emitted electrons are driven toward the anode

Answer 63

Saturation current

Question 64

The anode assembly

Answer 64

Anode Stator Rotor

Question 65

Positive side of the tube

Answer 65

Anode

Question 66

Functions of anode

Answer 66

Electrical conductor Mechanical support Thermal dissipator

Question 67

Anode materials

Answer 67

Copper Molybdenum Graphite

Question 68

It conducts electricity, radiates heat and contain the target

Answer 68

Anode

Question 69

Types of anode

Answer 69

Stationary | Rotating

Question 70

Used in dental imaging system | Portable imaging machines

Answer 70

Stationary anode X-ray tube

Question 71

Use in general purpose X-ray tube

Answer 71

Rotating anode X-ray tube

Question 72

Capable of producing high intensity X-ray beams in a short time

Answer 72

Rotating anode X-ray tube

Question 73

Allows beam to interact with much larger target area

Answer 73

Rotating anode X-ray tube

Question 74

Heat is not confined to a small area

Answer 74

Rotating anode X-ray tube

Question 75

Does not move when exposure occurs

Answer 75

Stationary

Question 76

Rotates during an exposure

Answer 76

Rotating anode

Question 77

Made of graphite

Answer 77

Base

Question 78

Made of tungsten-rhenium alloy

Answer 78

Target

Question 79

Made of molybdenum

Answer 79

Parts holding the target

Question 80

Area of the anode struck by the electrons

Answer 80

Target

Question 81

Entire rotating disk is the target

Answer 81

Rotating anode

Question 82

The target material in stationary anode

Answer 82

Tungsten alloy embedded in the copper anode

Question 83

Target material of rotating anode

Answer 83

Tungsten with rhenium

Question 84

Uses of molybdenum and graphite under the tungsten target

Answer 84

Anode lighter | Easier to rotate

Question 85

Tungsten as material of choice

Answer 85

``` Atomic number (74) Thermal conductivity High melting point ```

Question 86

A measure of the ability of the substance to conduct heat

Answer 86

Thermal conductivity

Question 87

A form of extremely localized corrosion that leads to the creation of small holes in the metal

Answer 87

Putting corrosion

Question 88

Actual target area for stationary tube

Answer 88

4mm2

Question 89

Total target area for rotating anode

Answer 89

1760mm2

Question 90

Rotating anodes revolve at

Answer 90

3600rpm

Question 91

High capacity tube rotates at

Answer 91

10,000rpm

Question 92

Shaft between anode and the rotor

Answer 92

Anode stem

Question 93

Stem is made of

Answer 93

Molybdenum (poor heat conductor)

Question 94

According to Crookes cathode rays travel in

Answer 94

Straight lines