Brain scans Flashcards
What does CAT scan stand for?
Computerised Axial Tomography scan
How do CAT scans work?
They involve passing X-rays into the head. Multiple beams are passed around the head from different angles to gather more information.
What are CAT scans useful for?
Detecting brain damage or the positioning of tumours in the brain
What do CAT scans produce?
Images of any part of the body, e.g. brain
What don’t CAT scans show?
How the brain functions - they only show the brain’s structure
CAT scans are less harmful than … scans because…
PET
CAT scans do not involve injecting a radioactive substance
CAT scans don’t involve going inside the body, so they are not…
invasive or painful
CAT scans are reliable because…
This means they can…
…they take place in laboratories with strict controls and a standardised procedure
…be easily replicated
CAT scans pose a risk to patients because…
they involve exposure to radiation (it is advised that they only be used when the possible benefits in relation to diagnosis outweigh the potential risks)
CAT scans are less useful than other brain scanning techniques…
e.g. PET/fMRI scans because they only show brain structure whereas PET/fMRI scans show functioning
What does PET scan stand for?
Positron Emission Tomography scan
What do PET scans produce?
Images that are in colour with high levels of activity shown by warmer colours (e.g. red) and low levels of activity shown by cooler colours (e.g. blue)
How do PET scans work?
Patients are injected with a small amount of radioactive material called fluorodeoxyglucose (FDG), a tracer substance where the radioactive atom is attached to glucose because the brain will use glucose up as a form of energy. Once the tracer has been absorbed into the bloodstream, a task may be given to encourage brain activity
Which mental disorder can PET scans be used to study?
Schizophrenia
PET scans help researchers to identify…
…and predict…
…abnormal levels of activity
…the issues the patient might face in relation to the brain activity identified
PET scans are reliable because…
This means they can…
…they take place in laboratories with strict controls and a standardised procedure
…be easily replicated
PET scans pose a risk to patients because…
they involve exposure to a radioactive tracer therefore can’t be carried out on the same patient too many times
(PET scans) When doing a task several areas of the brain are being used a the same time, meaning…
it can be difficult to isolate brain function using PET scans
PET scans take place in small environments and patients are required to remain still during the process, meaning…
there may be an issue with claustrophobia
PET scans involve an injection so they are…
slightly invasive
What does fMRI scan stand for?
Functional Magnetic Resonance Imaging scan
What do fMRI scans measure and how?
Brain activity by detecting changes associated with blood flow
What is the difference between MRI scans and fMRI scans?
MRI scans view anatomical structure
fMRI scans view metabolic function
During fMRI scans, patients are required to…
lie flat and still in a large dude called an electromagnet
(fMRI scans) As neural activity in the brain increases…
blood flow increases in active areas
The fMRI scanner detects … and sends … creating a … showing…
The scanner detects CHANGES IN THE BRAIN and sends INFORMATION TO THE COMPUTER creating a MAP OF ACTIVATION showing CHANGING LEVELS OF NEURAL ACTIVITY
fMRI scans measure blood flow, so there is no danger from…
radiation
fMRI scans are reliable because…
This means they can…
…they take place in laboratories with strict controls and a standardised procedure
…be easily replicated
fMRI scans take place in small environments and patients are required to remain still during the process, meaning…
there may be an issue with claustrophobia
fMRI scans do not work for all patients because…
they use high-powered magnetic fields, so might not work for anyone with a cardiac pacemaker or who has had recent surgical implants, as well as anyone who is claustrophobic or unnerved by confined spaces or loud noises
fMRI scans aren’t as useful as pet scans because…
PET scans produce more precise and detailed images, e.g. they show receptors
