6. X-RAYS

Question 1

1. What does this diagram show?

Answer 1

• it shows the Cross-Sectional View
  of the basic geometry for forming a radiograph
• it can also form a Diagnostic X-Ray Image

Question 2

2. Provide descriptions for the aspects labelled 1 and 2.

Answer 2

1. These are X-Rays
   
   • some of the X-Rays will be absorbed into the tissue of
     the body
   • this is a result of Photoelectric Absorption
2. This is the Image Receptor
   
   • this is where the formation of the image happens

Question 3

3. What does this image show?

Answer 3

• this is an X-Ray Tube
• it has a protective shield
• this is called the Tube House

Question 4

4. What does the Tube House (Protective Shield) do?

Answer 4

• it keeps the tube cold inside
• the shield is made form Lead
• this ensures that there is no Radiation leakage

Question 5

5. When are X-Rays produced?

Answer 5

• they are produced when highly energetic electrons
  interact with matter

Question 6

6. What energy conversion happens when X-Rays are produced?

Answer 6

• 1% of Kinetic energy is turned into Electromagnetic
  Radiation
• 99& of the energy is lost
• it is converted to Heat Energy

Question 7

7. What 4 parts does a device that produces X-Rays in Diagnostic Energy Range have?

Answer 7

1. An electron source
2. An evacuated path for electron acceleration
3. A target electrode
4. An external Power source to provide high voltage
   (this accelerates the electrons)

Question 8

8. Provide the names and descriptions for the parts labelled 1-5 of the diagram

Answer 8

1. The Voltage defines the Kinetic Energy
   
   • it accelerates the electrons
2. The Anode is positively charged
3. This is the Electron Source
4. The Cathode is negatively charged
5. This is where the electrons decelerate

Question 9

9. Provide the names and descriptions for the parts labelled 6-7 of the diagram

Answer 9

6. This is a glass container
   
   • it is filled with Mineral Oil
   • this ensures that there is a vacuum
   • this ensures there is electric insulation
   • this prevents energy loss
7. The Current
   - this gives us the number of the electrons
   - it also gives us the intensity of the X-Ray beam

Question 10

10. What 2 aspects does the X-Ray Tube insert consist of?

Answer 10

1. An electron Source
2. The target within an evacuated glass or metal
   envelope

Question 11

11. What does the Tube Housing Provide?

Answer 11

1. Protective Radiation Shielding
2. It cools the X-Ray Tube Insert

Question 12

12. What do X-Ray beam filters shape?

Answer 12

• they shape the x-Ray energy spectrum

Question 13

13. What are the X-Ray filters usually made out of?

Answer 13

• they are made out of materials that have low Atomic
  Numbers

Question 14

14. What is absorbed into the X-Ray filters?

Answer 14

• low energy photons from the X-Ray
• this removes the low energy photons
• this protects the patient from unhealthy radiation

Question 15

15. Why are low energy photons dangerous for the patient?

Answer 15

• these photons have deficient energy to reach the
  detector
• these photons will b absorbed by the patient’s body
• there are no benefits to this scenario

Question 16

16. What are the functions of the X-Ray Generator?

Answer 16

1. It supplies the voltage
   - this accelerates the electrons
2. It permits the control of the X-Ray beam
   characteristics

Question 17

17. Which components of the X-Ray tube work together to create a beam of X-Ray photons?

Answer 17

• the X-Ray Tube insert
• the Tube Housing
• the X-Ray Generator
• the X-Ray Beam Filters

Question 18

18. List 3 characteristics of X-Ray Photons?

Answer 18

1. They have a well-defined intensity
2. Penetrability
3. Spatial Distribution

Question 19

19. List 5 characteristic of X-Rays?

Answer 19

1. Invisible
2. Cannot be heard
3. Cannot be detected by the human body
4. They have no odour
5. They are not affected by electric or magnetic fields

Question 20

20. What are X-Rays commonly referred to as?

Answer 20

• Photons
• they have the ability to ionise other substances
  (EG: air)

Question 21

21. What does the term “Ionise” mean?

Answer 21

• the photons will pass through atoms
• they will cause these atoms to eject electrons from
  their electron shells

Question 22

22. What does Ionisation account for?

Answer 22

• it accounts for Imaging Properties
• it accounts for potential harmful effects

Question 23

23. What happens to the scattered electrons?

Answer 23

• they can be absorbed
• they ca be scattered in different media

Question 24

24. In which 4 ways can we detect X-Rays?

Answer 24

1. Their ability to ionise other substances
2. Their ability to cause Florescence
3. Their ability to give rise to colour changes
   
   • this can happen in several substances
   • EG: Barium Platinocyanide
4. Their ability to produce changes which can be made
   visible in photographic film
   
   • this is the process that is used in Medicine

Question 25

25. What part of the X-Ray equipments counts for most of it?

Answer 25

- the Rotating Anode X-Ray Tubes - this will dissipate heat over larger areas - this helps to avoid the melting of the target

Question 26

26. What are Rotating Anode X-Ray Tubes used in?

Answer 26

- they are used in all major Diagnostic Radiology Equipment

Question 27

27. Where can we find Stationery Anode X-Ray Tubes?

Answer 27

- in dental equipment - in small portable machines

Question 28

28. What two components does an X-Ray Tube consist of?

Answer 28

1. THE INSERT - this is evacuated - this is where the X-Rays are produced - it is kept in a glass envelope that is filled with mineral oil 2. THE TUBE SHIELD - this supports the insert - it is responsible for electrical radiation and safety

Question 29

29. The X-Ray Tube has 6 functions. Name 3 of them.

Answer 29

1. To provide a beam of X-Rays from as near to a point source as possible - this is known as the Focus 2. To dissipate the heat produced effectively - this prevents damage to the X-Ray tube 3. To provide a consistent quality (kVp) - and a consistent quantity (mAs) of radiation

Question 30

30. The X-Ray Tube has 6 functions. Name another 3 of them.

Answer 30

1. Allows the X-Rays to emerge only from the window (port) of the housing of the tube 2. To provide electrically safe environment for the practitioner 3. The tube is securely supported - it is still capable of easy movements into any position - it then stays maintained in that position

Question 31

31. What materials are used in the Tube Housing?

Answer 31

- steel construction - it is lined with lead - the port is the only part that is not lined with lead - this is because the lead absorbs the X-Rays

Question 32

32. What materials are used in the Port?

Answer 32

- Plastic - Beryllium - Mineral Oil - this is used as the insulation between the housing and the insert

Question 33

33. What materials are used to make the Insert (Tube Envelope)?

Answer 33

- metal or ceramics (ceramics is the more modern approach) - borosilicate glass

Question 34

34. What materials are used to make the Filament (Cathode) Assembly/Focusing Cup?

Answer 34

- Nickel - Stainless Steel

Question 35

35. What is the Filament made out of?

Answer 35

- Tungsten - it has a high atomic number

Question 36

36. What is the Anode Disc made out of?

Answer 36

- Molybdenum Alloy - Graphite Disc - Tungsten alloys (90%) - Rhenium alloys (10%)

Question 37

37. What is the function of the Tungsten and Rhenium Alloys?

Answer 37

- they prevent the Crazing effect from happening - this is when cracks can happen on the anode surface

Question 38

38. What is the Anode stem made out of?

Answer 38

- Molybdenum

Question 39

39. What are the Stator wings made out of?

Answer 39

- Copper

Question 40

40. What is the Additional Filtration made out of?

Answer 40

- Aluminium - Copper