Target Volume Localisation Flashcards
1
Q
Steps of treatment planning process (x10)
A
- Immobilisation
- Tumour localisation
- Virtual representation of patient
- Selection of treatmen geometry
- Optimisation of dose distribution
- Calculation of Dose and MU required
- Independent Dose verification
- Documentation of treatent information
- Verification of treatent set-up
- Treatment Delivery
2
Q
Purpose of immobilisation (x2)
A
- Reproducible patient position
- Appropriate position for treatment and delivery geometry
3
Q
6 Desireable characteristics of Immobilisation
A
- Easy to use
- Easy to produce
- Patient comfort
- resistance to bending and stretching
- Minimal attenuation of beam
- Minimal imgaing artefacts
4
Q
Purpose of Tumour Localisation
A
- Identify gross tumor volume (GTV)
- Identify multi-focal disease or nodes
5
Q
6 Methods of localisation
A
- Direct visualisation - look or by touch
- Simulator - x-ray set on gantry, outdated now
- CT - god for lungs, not enough soft tissue contrast for others
- MRI - Soft tissue contrast and differentiation of pathology
- Ultrasound - prostate and bladder, brachy
- PET-CT - metabolic imaging, needs to be combined with CT for anatomical information
6
Q
Different ways to represent a patient:
A
- separation - 1D patient is box of water, only appropriate for parallel-opposed pairs, measured along central axis
- Manual contour - 2D, wire used to transfer axial contour ro paper.
- CT slice - 2D
- CT Volume - 3D, multiple slices, most modern planning systems.
7
Q
positives & negatives of CT Volume patient representation:
A
Positives
- Geometric accuracy
- HU to map electron density
- Good res
- Good bone contrast
- Image fusion and data transfer
- Image manipulation (window and level)
Negatives
- Poor soft-tissue contrast
8
Q
What do you need to localise a tumour for RT treatment?
A
- Patient
- Imaging equipment
- Immobilisation
- Method of patient marking for allignment in treatment room
- Software application to define treatment geometry
- Method of dose calculation
9
Q
A