Rays And ECGs Flashcards
What is ionising radiation
Radiation that turns atoms into ions by removing some of its outer electrons
Which x rays are more powerful
High frequency or low
High
The higher the frequency, the more energy they have
What are the parts of an x ray
Vacuum tube
Cathode filament
Rotating anode
What is thermionic emission
The process that happens when a cathode is heated and become an electron gun and shoots electrons
How does an x ray work
Cathode filament is heated so it shoots electrons.
Potential difference builds between anode and cathode
When it’s high enough, the electrons accelerate towards the anode
As anode is metal, electrons quickly decelerate and kinetic energy becomes thermal and x rays
Currant formula
I = n * q I = currant N= number of particles per second Q= charge of each particle in coulombs
Kinetic energy equations
1/2 * mass * velocity squared
Charge of electron * potential difference (in volts)
What makes an x ray show what it shows
Denser areas are white as the absorb more X-rays, darker areas are less dense such as tissue. This is because the more x ray is absorbed, the less is detected so the lighter it is in the image
How do cat scans work and what do they make
Patient goes into a cylinder. The cylinder had a rotating x ray and detector opposite from the x ray source. This moves 360 around the patient and can build up a 3D cross section image of the patient
Benefits of digital x ray over traditional
Digital, image can be saved, altered so that less dense areas are lighter and dense become dark. So cancers can be detected
What is a fluoroscope
A x ray and a digital detector that shows a live video of the internals of the patient
Risks and benefits to cat and fluoroscope
Both painless and non invasive. No need for biopsy
Give a dose of equivalent of 10 years of background radiation. Could increase chance of cancers.
