Radiology Flashcards
Who Discovered Radiation?
Henry Becquerel
Who named X rays?
William Roentgen
When did William Roentgen win a Nobel Prize?
1901 in Physics
As well as radiation, what else did Henry Becquerel discover?
The uranium rays were weaker than X rays
When did Henry Becquerel win a Nobel Prize?
In 1903, with Marie Curie, for Physics
What did marie curie discover?
That radium and polonium were radioactive.
Also that uranium rays remained constant , therefore discovering Radioactivity
When did marie curie win the nobel on her own?
1911 for Chemistry
What are the 3 types of radiation known as ‘ Ionising Radiation’?
Alpha beta and Gamma
What does ionising radiation do?
Causes damage to matter that it strikes
Describe Alpha particles
Charged Particles
Not particularly strong penetrative powers
Stopped by Paper
Hazardous via inhalation or open wounds - not used in radiation medicine
Describe Beta Particles
Particle nature
Stopped by water, glass and metal
Dangerous if enter body
Describe Gamma radiation
Emitted during decay
Greatest penetrative power of the ionising radiations
Absorbed by lead or concrete
Similar to X rays (except gamma rays are naturally produced)
Stronger than X rays (manually produced)
What is radiation measured in ?
millisieverts - mSv
What are the 2 types of energy involved in X ray technology?
Electrical and Electromagnetic
On the EM spectrum, what happens to the strength of the radiation as the wavelength increases?
As the wavelength increases, the radiation gets weaker. The shorter the wavelength the stringer the radiation
What is the frequency of the radiation linked to in terms of X raying?
The kV -i.e. the penetrative power
What are features of all radiation on the EM spectrum?
- do not require a medium for transmission
- pass through a vacuum
- travel in straight lines
- travel at the same speed in a vacuum
- they interact with matter being absorbed or scattered
What are the additional properties of X rays to those shared by all of the EM spectrum rays?
Penetrate through skin and bone
- have an effect on photographic film
- fluoresce i.e. give off light
Who listed the unique properties of X rays?
William Roentgen
What is the smallest part of the element?
The atom
What is an element?
The smallest particle of a substance
What happens when an X ray machine is turned on?
Heat is applied to the cathode of the tube head i.e. the tungsten filament. (via an electronic current)
What does heat do the electrons in the cathode of a tube head?
It excites them.
The electrons move further and further away from the nucleus of the atom and eventually escape orbit.
This is known as ‘boiling off’ or ‘excitation stage’
What happens to the electrons after they are boiled off?
The are directed to the anode from the cathode by the focussing cup. The energy from the high speed movement of these electrons and the impact with the anode, produces 1% X rays and 99% heat
Describe the structure of the tube head
make sure you can label a diagram!
Tungsten Filament within a focussing cup. Sitting opposite, the target anode attached to a copper stem. These are all within a vacuum in a glass envelope. The glass envelope is surrounded by a lead lined metal shield, and between these layers is oil. There is a gap in the metal shield covered by an aluminium filter. There are also cooling fins behind the copper stem.
What does altering the kV do in terms of how X rays are produced?
It alters the speed at which the electrons are moved and how fast they hit the target. Therefore altering the energy or penetrating power of the X rays produced
What is the function of the lead lining?
Ensures X rays do not escape the tube head
What is the function of the GLASS ENVELOPE?
creates a vacuum containing the cathode and anode
What is the function of the vacuum?
Needed to allow the X rays to travel in a straight line (lack of O2 molecules to bounce off of and cause a direction change)
What is the function of the focussing cup? What is it made of?
Directs electrons toward the anode
Made of nickel or molybdenum (materials capable of withstanding very high temperatures and poor conductor of heat. Has a high melting point
What is the function of the cooling fins?
Disperse the Heat
What is the function of the Filament? What is it made of?
Made of Tungsten as has high melting point
Part of the cathode
Releases electrons when heated
What is the function of the target? What is it made of?
The anode
Subjected to bombardment
Also made of Tungsten as 99% energy produced is heat.
Base of target area is copper
What is the function of the copper stem?
Good conductor. Draws heat away from the Tungsten Target
What is the function of the oil?
Transfers heat away from the cathode
What is the function of the filter? What is it made of?
Aluminium
Covers window
Absorbs any soft X rays
