Xray Tube

Question 1

What is part of the cathode ?

Answer 1

Filament and focusing cup

Question 2

What charge is the cathode

Answer 2

Negative

Question 3

What charge is the anode

Answer 3

Positive

Question 4

What kind of material is the filament made of ?

Answer 4

Thoriated Tungsten

Question 5

What material is the focusing cup made of

Answer 5

Nickel

Question 6

Target

Answer 6

May also be called the focal point, focal spot, or the focal track

Question 7

Tube housing

Answer 7

Protects against leakage radiation and electric shock

Question 8

Thermionic Emission

Answer 8

The process of boiling off electrons and produces a cloud of electrons by heating the filament

Question 9

Space charge effect

Answer 9

Occurs when no more electrons can be boiled off the filament

Question 10

Three components of anode.

Answer 10

Anode, stator and rotor

Question 11

Is the primary thermal conductor of the tube

Answer 11

Anode

Question 12

Two types of anodes

Answer 12

Rotating and stationary

Question 13

Portion of the anode struck by electrons

Answer 13

Target

Question 14

What is the anode made up of

Answer 14

Tungsten rhenium alloys

Question 15

What does it mean to have two filaments

Answer 15

Dual focus tube

Question 16

Why does the X-ray tube need to be warmed up

Answer 16

Prevent cracking and maintain vacuum

Question 17

Purpose of rotating anode

Answer 17

Promote greater heat dissipation

Question 18

What determines the number of electrons boiled off

Answer 18

mA

Question 19

Anode heel effect

Answer 19

Absorption of X-rays produces in the tube by the anode, causes uneven distribution of X-ray intensity between the cathode and anode, more intensity on cathode side (fat cat)

Question 20

Project area of X-ray beam

Answer 20

Effective focal spot

Question 21

Cardinal rules of Radiationg Protection developed to prevent radiation injury

Answer 21

Time, distance, shielding

Question 22

Why is tungsten used

Answer 22

High melting point and Difficult to vaporize

Question 23

Atomic number of tungsten rhenium alloy

Answer 23

74

Question 24

Who was the first fatality from X-rays in 1904

Answer 24

Clarence Dally

Question 25

Area where electrons strike the anode

Answer 25

Focal spot

Question 26

Who devised a fluoroscope

Answer 26

Thomas Edison

Question 27

Who improved the crooked tube

Answer 27

William Coolidge

Question 28

What was the first ever xray

Answer 28

Roentgens wife’s hand

Question 29

Leakage radiation limit

Answer 29

100 milliroentgens per hour at 1 meter

Question 30

When was X-rays discovered

Answer 30

Nov 8, 1895

Question 31

Physical area of the focal track being hit by the electrons.

Answer 31

Actual focal spot

Question 32

What is the environment inside the X-ray tube once all air has been removed

Answer 32

Vacuum

Question 33

Who discovered X-rays

Answer 33

Wilhelm Conrad roentgen

Question 34

Necessary qualities of the anode

Answer 34

High atomic number, high melting point, and high heat conduction ability

Question 35

Heat tolerant Pyrex glass or metal

Answer 35

Envelope

Question 36

What do electrons become when they hit the anode

Answer 36

Photons

Question 37

What two things control the size of the effective focal spot

Answer 37

Size of the actual focal spot and anode target angle

Question 38

What is the line focus principle

Answer 38

Spreads heat over a greater area of the anode and allows the effective focal spot to be smaller than the actual focal spot

Question 39

What is the purpose of the glass envelope

Answer 39

Absorbs X-rays and ensure a vacuum

Question 40

Purpose of the focusing cup

Answer 40

To group the electrons for their passage to the anode

Question 41

A molybdenum shaft is used to connect the anode to the rotor because

Answer 41

It is a less dense metal with a high melting point that helps anode to spin faster

Question 42

Purpose of the fan in the tube housing is to

Answer 42

Promote heat dissipation

Question 43

Average anode rotation speeds in diagnostic ray tubes are in the ranges of :

Answer 43

3,000-10,000

Question 44

These are all apart of production of X-rays

Answer 44

Electrons, target, high voltage , and vacuum

Question 45

Is made of molybdenum and connects the anode to the rotor

Answer 45

Stem

Question 46

What is the X-ray efficiency

Answer 46

1% X-ray , 99% heat

Question 47

The only thing located outside of the envelope that consists of copper windings

Answer 47

Stator

Question 48

Made of a copper cylinder in the step of the X-ray tube and is support by the high strength ball bearings

Answer 48

Rotor

Question 49

What are two types of cathode failures

Answer 49

Tube arcing and filament breakage

Question 50

What is it called when they are holes on the focal track

Answer 50

“Pitting”

Question 51

What is anode layering

Answer 51

Assists with heat loading and increases X-ray tube thermal capacity. It is backed with molybdenum or graphite

Question 52

What does the protective housing consist of

Answer 52

Metallic , supports X-ray tube, controls leakage and scatter radiation, provide mechanisms to cool tube

Question 53

How can we extend the tube life

Answer 53

- tube warm up - avoid frequent “boosting” -use low mA when possible - use low speed rotation when possible - follow rotating charts - avoid rough handling - listen to unusual sounds

Question 54

What is off focus radiation

Answer 54

Undesirable part of the beam , not hitting anode, low energy and no diagnostic value, produces “ghosting”

Question 55

What does X-ray stand for

Answer 55

The x in X-ray means unknown

Question 56

What is the divergence of the beam

Answer 56

Energy that is coming out and what’s interacting with the patient

Question 57

True or false X-rays are invisible

Answer 57

True

Question 58

True or false X-rays can travel around corners

Answer 58

False

Question 59

True or false Taking X-rays is a safe profession

Answer 59

True

Question 60

True or false Radiation can cause harm to your body

Answer 60

True

Question 61

Sequence of taking X-rays

Answer 61

1. Current runs through the filament circuit 2. Filament gets hot 3. Filament glows 4. Filament boils of electrons 5. Electrons form a space cloud 6. Electrons are repelled from the focusing cup 7. Electrons are attracted by the anode 8. Electrons move over to the anode 9. Electrons slam into the anode at the target 10. Electrons lose energy 11. Light, heat and X-rays are produced 12. Focal spot if formed 13. X-rays are emitted isotropically 14. X-rays are absorbed by the glass and metal housing

Question 62

True or false X-rays are electrically neutral

Answer 62

True

Question 63

True or false X-rays have mass

Answer 63

False (X-rays have no mass)

Question 64

True or false X-rays can be focused

Answer 64

False - can’t be focused or refracted

Question 65

True or false X-rays travel in straight lines

Answer 65

True

Question 66

ways to avoid dangers of radiation

Answer 66

- never stand in primary beam -collomating as small as you can - never hold patient -lead protection - radiation dose monitored through use of dosimeter

Question 67

what type of body parts would the small filament focus on

Answer 67

small focusing body part (less heat)

Question 68

what type of body parts would the large filament focus on

Answer 68

large focusing body parts (more heat)

Question 69

what does the filament produce

Answer 69

filament produces electrons to produce image

Question 70

what does the filament length and width impact

Answer 70

recorded detail or special resolution

Question 71

Typically controlled by the xray circuitry and wont go hight that what is already set

Answer 71

Saturation Current