Question 20N.3.HL.TZ0.17
| Date | November 2020 | Marks available | [Maximum mark: 4] | Reference code | 20N.3.HL.TZ0.17 |
| Level | HL | Paper | 3 | Time zone | TZ0 |
| Command term | Explain, State | Question number | 17 | Adapted from | N/A |
The photograph shows an X-ray image of a hand.
© International Baccalaureate Organization 2020.
Explain how attenuation causes the contrast between soft tissue and bone in the image.
[3]
bone «denser so» absorb rays «and appear white in the negative» ✓
larger attenuation for bone ✓
muscles have less attenuation, so rays pass through «and appear darker» ✓
Accept the reversed argument
Candidates successfully answered in terms of absorption and managed to score two marks but not all of them.
X-ray images of other parts of the body require the contrast to be enhanced. State one technique used in X-ray medical imaging to enhance contrast.
[1]
collimation ✓
fluorescent screens «each side of photographic plate» ✓
barium/magnesium meal ✓
Almost all candidates were familiar with different techniques to enhance contrast. A barium meal was the most popular one.
