Brain scans Flashcards
What are the three different types of brain scans?
MRIs
PET
EEG
What does MRI stand for?
magnetic resonance imaging
How do MRIs work?
A magnetic feild created round the body causing hydrogen atoms to move
-when the magnet is switched off the hydrogen atoms go back to orgional position creating an electroagnetic signal
-signals detected creating an mri image
-producing a 2d image of the brain, these are cross sectional
How long does an MRI scan take?
-a single shot can be 3-8 minutes
-a total shot can be 15-90 minutes
Strengths of MRI?
-no harmful radiation
-detailed images
-allows brains to be investigated
-objective investigation of brain activity
Disadvantages of MRI?
-mris take a long time and can be uncomfortable
-only produces 2d imaging
-expensive
What does a PET scan stand for?
Positron emission tomography
How do PET scans work?
-we inject a radioactive tracer combined with sugar into the patient as brain uses glucose by a radioactive tracer
-brain uses the positron moving round the brain, these positrons collide with the electrons releasing gamma rays
-more active part of the brain has the most active positron movement
-between 10 minutes a picture of the brain is built up
How long does a PET scan take?
45-60 minutes
What are the advantages of a PET scan?
-less claustrophobic
-when scans are being done patients can move around
-extremely effective in locating tumors
What are the disadvantages of a PET scan?
-use of tracer can be uncomfortable and invasive
-side effectives’
-unacceptable for pregnant women
-can still be claustrophobic
What does an EEG stand for?
electroencephalogram
How does an EEG work?
-place electrodes on the scalp
-electrodes record electrical impulses in the brain
-creating a visual display of the electrical activity in the brain
How long does an EEG take?
20-40 minutes
Advantages of EEG?
-cheeper
-non invasive
-risk free
-no radiation
