62. RADIOTHERAPY: BRACHYTHERAPY

Question 1

1. Define Brachytherapy.

Answer 1

• it is the short distance treatment of cancer
• it uses radiation from a small, encapsulated
  Radionuclide Source

Question 2

2. How is Brachytherapy given?

Answer 2

• it places sources directly into the volume to be treated
• the sources can also be placed near to this volume

Question 3

3. How is the dose delivered during Brachytherapy treatments?

Answer 3

• the source is delivered continuously
• it is delivered over a short period of time

IT CAN ALSO BE DELIVERED:
- over the lifetime of the source
- until the source completely decays

Question 4

4. What do most of the common Brachytherapy sources emit?

Answer 4

• they emit photons

Question 5

5. What are the two main types of Brachytherapy treatment?

Answer 5

1. Intracavitary
2. Interstitial

Question 6

6. What is Intracavitary Brachytherapy?

Answer 6

• the source of radiation is placed in the body cavity
• this is placed close to the tumour volume

Question 7

7. What is Interstitial Brachytherapy?

Answer 7

• the sources are implanted within the tumour volume

Question 8

8. How long do Intracavitary Brachytherapy treatments last?

Answer 8

• they are always temporary
• they have a very short duration

Question 9

9. How long do Interstitial Treatments last?

Answer 9

• they can be temporary
• they can also be permanent

Question 10

10. How are temporary implants inserted?

Answer 10

• they are inserted using manual procedures
• they can also use remote after-loading procedures

Question 11

11. What is a physical advantage of Brachytherapy?

Answer 11

-it has improved the localised delivery of the dose
- to the target volume of interest

Question 12

12. What is a disadvantage of Brachytherapy?

Answer 12

• it can only be used in cases in which the tumour is well
  localised and relatively small

Question 13

13. What percentage of patients is treated with Brachytherapy, when we examine the typical radiotherapy department?

Answer 13

• about 10 to20 percent of all Radiotherapy patients are
  treated with brachytherapy

Question 14

14. What must we consider when giving Brachytherapy treatments?

Answer 14

• the way that the sources are positioned relative to the
  volume that we want to treat

SEVERAL DIFFERENT MODELS HAVE BEEN DEVELOPED:
- for this exact purpose

Question 15

15. What is the advantage of using a well-established model?

Answer 15

• the patient will benefit from the long experience that
  they will have with this model

Question 16

16. What is the benefit of using uniform models and methods in Brachytherapy treatments?

Answer 16

• it simplifies the comparison of the Treatment Results

Question 17

17. When does a Brachytherapy treatment fail to reach its goal?

Answer 17

IT FAILS TO REACH ITS GOAL:
- if the source misses its aimed position
- by a large margin
- this is known as a Geometrical miss

Question 18

18. Why can Geometrical misses be detrimental?

Answer 18

• it will affect the steep dose gradient
• this is characteristic to Brachytherapy

Question 19

19. What do we need a Quality Control Programme for?

Answer 19

• it guarantees that the treatment is given in accordance
  with its purposes

Question 20

20. What can influence the Therapeutic Outcomes of a Brachytherapy treatment?

Answer 20

• the delivery of the Brachytherapy dose
• this results in Complex Dose Rate effects