What is an x-ray? Flashcards
What is an x-ray?
It’s a wave packet of energy called a photon.
It can penetrate human tissues and create an image
Who discovered x-rays?
Wilhelm Roentgen (1895)
Do all x-ray machines produce the same photons?
No
Why don’t all photons pass through the patient?
Because they have different energy levels: low energy stop inside a patient, high energy can pass right through
Is it just one photon required to take an x-ray?
No, it uses millions of photons to constitute an x-ray beam
Are wavelengths of x-rays considered long or short?
Short
Do x-rays have high photon energy or low?
High - it’s ionising radiation
What is the difference between x-rays and gamma rays?
Nothing, they are identical. They are both ionising.
BUT x-rays are man-made, but gamma rays are naturally occurring
What produces gamma radiation?
Radioisotopes.
Rocks and soil in earth’s crust, outer space, certain foods
Approx how much background gamma radiation does a person annually receive?
~ 2.6 mSv
What 4 things that can happen when an x-ray hits a pt?
Transmitted unchanged (high energy).
Absorbed (low energy and disappears)
Scatter + absorption (some loss of energy)
Pure scatter ( no loss of energy)
What is the trajectory of an x-ray?
They travel in straight lines
What medium is required for x-rays to work?
No medium is required
What level do they interact at in the patient?
They interact at an atomic level
How are the damaging effects of x-rays classified?
- Somatic deterministic effects (certainty effects) - can be acute or chronic
- Somatic stochastics effects
- Genetic stochastic effects
