Th - Pre-treatment imaging Radiotherapy Flashcards
What kind of radiation is used for CT imaging?
High energy photons
What kind of radiation is used for radiotherapy?
Even higher energy photons
Does CT account for a dose burden?
Yes, it does (mSv)
Why is target delineation so important in radiotherapy (RT)?
Needs to encompass the tumor (and spread)
How do we handle delineation uncertainties?
Apply margins
What kind of error is a delineation error?
Delineation is systematic (not random) and is thus a large component in the margin.
An error in the co-registration lead to what kind of error?
Systematic
Co-registration of multiple modalities have residual mismatches. Can you name a few reasons for these mismatches? (3)
Inter-observer error
Organ motion
Organ deformation
What are ways to incorporate respiratory motion in radiotherapy? (4)
Increase margins
Gated RT (beam on/off)
Tracking (following the motion)
Minimize respiratory motion (breath-holding)
Give examples on how pre-treatment CT is enhanced for RT (1)
-> personalized treatment
What are in general the main reasons why imaging is always performed before any radiotherapy treatment is delivered. (4)
Tumor location/extent Motion, organ motion, characterisation
What is the trade off-challenge in radiation therapy?
The trade-off challenge is do you want to put in more radiation and kill the tumor, but it will also kill off the surrounding tumor? Or other way around?
Explain why cancer radiotherapy needs to be personalized
Needs to be personalized because no two people and tumours are the same
