Date post: | 11-May-2015 |
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Different types of scans and imaging
THE BRAIN
MRI/MRAUses magnetic field and
radio wavesThe nuclei of atoms line up
in the direction of the magnetic field
Hydrogen atoms in water are monitored
The hydrogen atoms become excited with more energy due to radio waves, once gone the energy is released and detected
Used in diagnosis of tumours, strokes, brain injuries and infections of the brain and spine
fMRIPossible to study human activitiesLooks at functions using oxygen uptakeDeoxygenhaemoglobin absorbs radio
wavesPart of brain activated needs more
oxygen, less radio waves absorbedCan produce 4 images per second
PET scanningPositron Emission TomographyDetects the radiation emitted
from radioactive substances injected into the body
Gamma rays given off are detected by PET
Gamma rays are converted to photons of light, and electrical signals
The signals convert into slices of images
Can show glucose metabolism in the brain, detect cancer, detect memory disorders and seizures, map brain function
CT/ CAT scanningComputerised Axial
Tomography Use thousands of narrow-
beam X-rays to pass through the tissue at different angles
X-rays are detected forming slices of images of the tissues
CT looks at structures rather than functions
Used to detect brain disease
Small structures cannot be distinguished
qEEG/ Brain MappingCan be used in real time as you don’t need
to keep stillSensors are attached to the scalp
measuring activity from thereThe main use is research into brain
functionNo risks (unlike CT scans for example)They are not as spatially accurate as fMRI