11. RADIATION HEALTH EFFECTS: FILTRATION ON THE X-RAY BEAM Flashcards
1
Q
- What is mass proportional to?
A
- the number of photons in the X-Ray beam
2
Q
- What does the X-Ray beam pass through in the process of leaving the X-ray Tube?
A
- it passes through certain components of the tube
- these are collectively called the Inherent Filtration
3
Q
- What is the Inherent Filtration made up of?
A
- The glass or ceramic envelope which maintains the
vacuum - The cooling oil
- The window of the X-Ray Tube
- this is usually make of Beryllium
4
Q
- What is the Inherent Filtration measured in?
A
- it is measured in Aluminium Equivalents (mm Al)
- the thickness of the Aluminium would produce the same
degree of attenuation as the thickness of the material in
question
5
Q
- What kind of added filtration does every X-Ray tube have?
A
- every X-Ray tube has external or added filtration
- this helps to remove lower energy
- this removes the softer X-Rays from the beam
6
Q
- Why do we want to remove the low energy photons?
A
DUE TO THE PHOTOELECTRIC EFFECT:
- low energy photons will be absorbed by the human body
- this will decrease the patients radiation protection
7
Q
- What are the added/external filters made of?
A
- Aluminium
- this will be used with the diagnostic range of the X-Ray
energies
8
Q
- Why do we use Aluminium?
A
- it has a low atomic number
- it will be more likely to absorb or scatter the low energy
photons
9
Q
- What can be said about low energy X-Rays?
A
- they have sufficient energy to increase patient radiation
doses - they do not have enough energy to contribute to the
radiographic image formation
10
Q
- Which material is a better filter for high energy radiation?
A
- Copper
11
Q
- What does the amount of filtration added depend on?
A
- it depends on the maximum generating voltage of the
tube - it is usual to have between 1.5mm - 2 mm of filtration
12
Q
- What are three important effects of Filtration?
A
1 . The process of filtration does not affect the E-Max
- The intensity of the beam will be decreased
(less photons) - The average energy of the beam will increase
13
Q
- What can be said about Beam quality?
A
- it is proportional to the filtration
- beam intensity is inversely proportional to the filtration
14
Q
- Which organisation determines Quality Assurance for Radiation exposure?
A
- the Council Directive 2013/59/EURATOM
15
Q
- What does Quality Assurance revolve around?
A
- it revolves around all the planned and symmetric actions
- that are necessary to provide adequate assurance
- that a structure, component or procedure will perform
satisfactorily in compliance with the agreed standards