medical imaging

Question 1

what is an X-ray

Answer 1

an ionising wave

Question 2

how do x-rays give images

Answer 2

X-rays put through person and detected on the other side. dense tissue absorbs more radiation and therefore shows up on X-ray

Question 3

what are the medial and lateral lines

Answer 3

medial = towards the midline and lateral = away from the midline

Question 4

medical language for the different planes

Answer 4

coronal- down the middle sagittal - the other way to coronal and transverse which is a horizontal plane

Question 5

where are left and right on an image

Answer 5

opposite to real life

Question 6

what is a CT scan and how does it work

Answer 6

uses X-rays all the way around the patient to give image. compiled by computer. Air has very low density so will show up as black on a CT and bone density is high so will show up white

Question 7

using contrast in a CT

Answer 7

highlights regions by adding density to show structures better

Question 8

what is fluoroscopy

Answer 8

serial xrays taken in sequence after addition of contrast to show dynamic flow through systems. little video kind of thing

Question 9

what is a PET scan

Answer 9

radioactively labelled substance usually glucose is injected and scanned to show tissue with high glucose. These are usually the metabolically active ones. cancer cells are very metabolically active so shown v clearly on PET scans or in epilepsy and cancer. see which parts of brain are functioning more or less

Question 10

what is an MRI

Answer 10

atoms usually spin in random direction but when a magnetic field is applied they line up either north or south. about half go one way or the other BUT a few are unmatched. when radio frequency is applied the unmatched atoms spin the opposite way and when its stopped spin back emitting energy. energy is detected by computer and uses it to create image

Question 11

what is T1 and T2?

Answer 11

T1= black, this is the colour of water 
T2= white , this is the colour of water

Question 12

what is ultrasound

Answer 12

sound waves travel into tissue and are reflected back off changes of density, detected by the computer and make an image. The reflections detected convert into an image based on the amount of time taken to return. Differentiates objects in different planes

Question 13

how can we improve the quality of ultrasound images

Answer 13

increasing the frequency will improve the resolution but will also decrease the penetration distance. one or the other.

Question 14

pros and cons of CT

Answer 14

pros- 
quick, 3-7 mins
cheap 
3D 
excellent view of bone tissue 
cons- 
poor image of soft tissue 
high radiation

Question 15

pros and cons of MRI

Answer 15

pros- 
3D 
excellent view of soft tissue 
no radiation 
cons- 
long time, 30-45 mins 
expensive 
poor image of bone tissue

Question 16

xray pros and cons

Answer 16

pros; 
quick, 2-3 mins 
cheap 
excellent view of bone tissue 
not too much radiation 
cons- 
2D 
soft tissue image is poor

Question 17

pros and cons of ultrasound

Answer 17

pros; 
quick, 5-10 mins 
cheap 
no radiation 
cons- 
2D
poor view of soft tissue AND bone