Need to Know for Formative

Question 1

Give three examples of X-Rays

Answer 1

Plain radiographs
Contrast Studies
CT Scans

Question 2

If tissue is dense, what does this mean for the x-rays that pass through it?

Answer 2

Fewer x-rays pass through

Question 3

_____ x-rays pass through air

Answer 3

all

Question 4

_____ x-rays pass through bone

Answer 4

no

Question 5

Film turns _____ when hit by x-rays

Answer 5

black

Question 6

When is an x-ray not ideal?

Answer 6

• When looking at soft tissues

- Looking at things of similar densities

Question 7

X-rays cause what?

Answer 7

Dose dependant cell DNA damage

So increased risk of cancer

Question 8

Advantages of using CT scans?

Answer 8

• Better contrast resolution
• Can distinguish between tissues of similar densities
• Cross sectional pictures, no superimposition of other structures

Question 9

Disadvantages of CT scans?

Answer 9

• High radiation dose

- Cannot distinguish very similar densities

Question 10

How do ultrasounds work?

Answer 10

• Uses sound
• Certain structures transmit waves
• Others reflect them producing the picture we get

Question 11

Advantages of ultrasounds

Answer 11

• No ionising radiation

- Ideal for soft tissue imaging, fluid collections

Question 12

Disadvantages of ultrasounds

Answer 12

• Bone and gas block the ultrasound

- Can’t really be used if obese

Question 13

How do MRIs work?

Answer 13

Magnetic field

• The body’s protons are energised by the RF pulse
• Scanner listens for return signal and creates the image

Question 14

Advantages of MRI

Answer 14

• No ionising radiation

- Best imaging of the brain, good for MSK

Question 15

Disadvantages of MRI

Answer 15

• Ferrous metals cannot go near as it is a giant magnet
• Takes ages
• Very expensive
• Claustrophobic
• Bad for lung imaging