66. RADIOTHERAPY: IMRT

Question 1

1. What happens in IMRT?

Answer 1

• the targets and the sensitive organs are defined
• the computer then designs the best treatment plan

Question 2

2. How does IMRT work?

Answer 2

• this technology delivers the radiation beams in
  multiple arcs

Question 3

3. What software does IMRT make use of?

Answer 3

• it makes use of sophisticated inverse planning
  software
• it uses multi leaf collimators

Question 4

4. What effect do the inverse planning software and the multi leaf collimators have?

Answer 4

• they shape the radiation beam
• they modulate the beam intensity
• this delivers the optimum dose

Question 5

5. What does IMRT stand for?

Answer 5

• Intensity Modulated Radio Therapy

Question 6

6. What led to the development of Treatment Simulators?

Answer 6

• the need for accurate verification of the treatment
  geometry

Question 7

7. What is the Simulator?

Answer 7

• it is a sophisticated diagnostic X-Ray set
• it localises the target tissues
• it verifies the treatment plan
• it has the same mounting and couch movements as
  the Treatment Accelerator

Question 8

8. What do we use the Radiographs that are taken by a Treatment Stimulator for?

Answer 8

• we use them to provide information on the Treatment
  Area for planning purposes
• we also use them to check the accuracy of the plans
• we use them to check the accuracy of the patient
  positioning

Question 9

9. What do we use Simulators for?

Answer 9

• we use them for the localisation of sealed sources
• these are used in Brachytherapy

Question 10

10. Is there a point in producing an accurate plan of the treatment if the position of the patient cannot be guaranteed?

Answer 10

• no

Question 11

11. What must happen with regards to the patient and their position?

Answer 11

• the patient must be marked
• they must be aligned correctly
• they must be placed in the correct position according
  to the beam
• they must remain stationary during the treatment

Question 12

12. What is this?

Answer 12

• this is a Patient Shell

Question 13

13. What do we use the Patient Shell for?

Answer 13

• it is used to position the patient
• it is usually fixed to the treatment couch

IT IS USED:
- in about 30% of patients
- it is used particularly for radical treatments of the
head and neck

Question 14

14. What are the aspects of Quality Assurance when it comes to Radiotherapy?

Answer 14

• commissioning of the new equipment
• interfaces between the various equipment
• characterising the data
• entering the data into the treatment plan
• quality assurance of the equipment

Question 15

15. How often should Quality Assurance of the Equipment be done?

Answer 15

• daily
• weekly
• monthly
• yearly

Question 16

16. How often should the Radiation be checked?

Answer 16

• daily
• weekly
• monthly
• yearly

Question 17

17. What aspects do we check in Daily Radiation Checks?

Answer 17

• constancy
  -the ionisation chamber

Question 18

18. What aspects do we check in Weekly Radiation Checks?

Answer 18

• the profiler

Question 19

19. What aspects do we check in Monthly Radiation Checks?

Answer 19

• the profiler
• the ionisation chamber

Question 20

20. What aspects do we check in Yearly Radiation Checks?

Answer 20

• the water phantom