Brain Health and Dementia 2a Flashcards
What is horizontal plane also known as?
Transverse.
Describe transverse plane?
cutting horizontally
Describe frontal / coronal plane?
cutting down through left to right
Describe sagittal plane
cutting down through the front.
What does PET scan stand for?
Positron Emission Tomography.
What is a Positron ?
Opposite particle to the electron
It is a particle
Positively charged
Symbol : β+ or e+
Emitted during radioactive decay
What is tomography?
Tomography is an x-ray technique in which shadows of superimposed structures are blurred out by a moving x-ray tube and produce detailed images of internal structures.
What is a positron the equivalent of?
The positively charged equivalent of an electron.
What is this an equation for? p → n + β^+ + νe
Beta plus decay generic equation.
Describe the equation for Beta Plus decay?
p → n + β^+ + νe
a proton decays into a neutron + positron + electron neutrino
Whats the charge of an electron?
negative charge (-)
Whats the charge of a positron?
positive charge (+)
What is the charge of a neutrino?
- Neutral charge.
What is neutrino represented by?
v
When are positrons emitted?
During radioative decay, also known as Beta+ decay (B^+)
What does a proton decay into in beta + decay?
a proton decays into a neutron + positron + electron neutrino
How often do positrons occur naturally?
almost never occurs naturally
What is the brains main source of energy?
Glucose is used as the main source of energy (krebs cycle).
Where in the brain is glucose used?
is used in the brain in the neurons and the cells.
What does the brain need in order to function?
The brain needs energy.
How could we measure where is glucose used ?
Use of non-hydrolysable (non-degradable) glucose molecules (glucose analogues)
- [18F] fluorodeoxyglucose
- used as a marker (tracer)
What do PET scans detect?
PET scans detect the emission of protons via indirect detection of the energy emitted by the 2 photons travelling in opposite directions.
Describe how a PET scan works.
1) Radioactive atom produces a positron
2) Travels a minute distance until it meets and electron. This distance is very small.
3) Positron and electron react and create a neutral charge.
4) Annihilation. Needs to release energy and does so by forming photons (Y) which travel in opposite directions.
5) Each photon has 511 keV. kiloelectronvolts.
6) t2 does not have to travel far to be detected by the machine so will be quick.
7) t1 has to travel further so will take more time for detection.
What are the different types of coincident events?
True coincidence, random (accident) coincidence, and scattered coincidence.
What is different with random (accident) coincidence, and scattered coincidence?
The annihilation event does not lie on the apparent line of response between two photon detectors.
What type of detectors are involved in PET scans?
photon detectors.
WHat is [18F] FDG used for?
use for visualization of metabolism
What is [15O] used for?
Used for visualisation of blood flow.
