Topic 8 - Medical Imaging

Question 1

Describe how a tumour shrinkage could be observed (2)

Answer 1

• Use of CT/MRI/PET scan
• Before and after treatment

Question 2

Explain how fMRI was able to show that certain areas in the brain became more active when people ate chocolate

Answer 2

▪︎ fMRI uses magnetic fields/radio waves

▪︎ fMRI allows brain activity to be seen in real time

▪︎ Areas of higher activity have more bloodflow/greater supply of oxygenated blood

▪︎ Oxygenated areas absorb fewer fMRI signals

▪︎ So theses show up as white

▪︎ Comparison between group with and without chocolate

Question 3

Why do tumours appear white on CT scans?

Answer 3

▪︎ Tumours are more dense than normal brain tissue
▪︎ So absorb more radiation, less radiation reaches detector

Question 4

Compare & contrast the use of CT and MRI for studying brain structure

Answer 4

• CT uses X-Rays while MRI uses magnetic fields/radio waves
• MRI gives a comparatively much clearer image than CT
• MRI scanners cost much more than CT
• Both provide an image of the brain which is frozen in time