Treatment Verification

Question 1

Why do we need immobilisation and verification?

Answer 1

1. Patient isn’t in same place each day
2. Patient don’t keep same position within treatment
3. Organs are not exactly in the same position in the body each day
4. Organs don’y stay in the same position over 15min treatment
5. Patients breathe

Question 2

Why don’e we just have very strict immobilisation?

Answer 2

• If patients are comfy they are less likely to move
• Messes with imaging less

Question 3

Treatment preparation errors:

Systematic (x4)

Answer 3

1. Doctor delinieation
2. Organ position and shape
3. Errors in planning system
4. Image registration

Question 4

Treatment Delivery Errors

Systematic (x2)

Random (x2)

Answer 4

Systematic (x2)

• Linac geometry
• systematic set-up

Random (x2)

• Daly set-up error
• Daily position and shape of organ

Question 5

Equation for patient random uncertainty (LOOK THIS UP)

Answer 5

• Number of images taken for patient
• shift relatice to reference image
• mean deviation for patient for all images

Question 6

How can you reduce systematic errors?

Answer 6

Sequence of images on successive days

Calc mean displacement

Appropriate corrective action

Question 7

How can you reduce systematic & random errors?

Answer 7

• Acquire image each day
• daily displacement calculated
• appropriate action