Brain Scanning

Question 1

CAT scans

Answer 1

CAT scans take a series of x-rays of the brain from different directions. The information from the x-rays is then interpreted by a computer.

Question 2

CAT scans strengths

Answer 2

It is useful for finding injuries in the brain and tumours, very quick to conduct, give details of the brain structure.

Question 3

CAT scans weaknesses

Answer 3

It does not tell doctors about how the brain is functioning, patients are exposed to radiation.

Question 4

PET scans

Answer 4

A small amount of radioactive materiel is injected into the patient. The radioactive atom will then attach to glucose. A task is then given to the patients and the glucose will be used up. As this happens the radioactive atom will start to break down and leave materiel. The scanner will then pick up the gamma rays and areas of high activity will have more gamma rays given off.

Question 5

PET scans strengths

Answer 5

Can detect areas of the brain showing abnormal levels of activity, not very much of the radioactive substance is injected so it is fairly low risk.

Question 6

Weaknesses

Answer 6

Most invasive type of brain scan, unclear as to whether there may be long term effects.

Question 7

fMRI

Answer 7

Measures how quickly oxygen is used by brain cells. It can be used to work out which areas of the brain are involved in a particular task as more active areas of the brain use more oxygen. It can measure the flow of blood as more oxygenated blood has a different magnetic quality from oxygenated blood.

Question 8

fMRI strengths

Answer 8

It is a non invasive procedure, has a spatial resolution of 1-2mm - psychologists can determine the activity of different brain regions with much greater accuracy.

Question 9

fMRI weaknesses

Answer 9

It has a spatial resolution of 1-4 seconds which is a lot slower than other brain scanning techniques. Can’t be used to show the communication between areas of the brain.