Imaging Modalities

Question 1

Which sites do we use KV imaging?

Answer 1

1. prostate
2. head and neck
3. oesophagus
4. radical brain

Question 2

What are the advantages of using KV images for these sites?

Answer 2

• reduces patient dose compared to MV
  -higher quality images compared to MV

Question 3

What are the disadvantages of using KV images for these sites?

Answer 3

-unable to see soft tissue
- not 3D

Question 4

Which sites do we use MV imaging?

Answer 4

breast, palliative extremity, whole brain

Question 5

What are the advantages of using MV images for these sites?

Answer 5

uses identical gantry to that used for treatment, less potential for collision risk

Question 6

What are the disadvantages of using MV images for these sites?

Answer 6

-MV delivers more radistion dose to patients.
-poor image quality/contrast due to larger compton scattering compared to KV

Question 7

Which sites do we use CBCT imaging?

Answer 7

lung, prostate bed, cervix, endometrium, breast, head and neck, bladder, SABR

Question 8

What are the advantages of CBCTs?

Answer 8

-superior soft tissue contrast
- can see soft tissue and patent external contour
- CBCT is 3D so can match to soft tissue target
-can evaluate the organs at risk

Question 9

What are the disadvantages of CBCTs?

Answer 9

-scatter from metallic artefacts can reduce image quality
- more dose compared to KV