Computer Planning? Flashcards
what is the overall aim of treatment planning?
95% coverage
spare normal tissue as much as possible
keep critical structures within limits
ensure daily treatment replicable and accurate
what is 2d planning?
planning on a single slice
what is hand/manual planning involve?
overlays to create Isodose maps
what is an appropriate slice thickness?
2-3mm
What is a good limit both superiorly and inferiorly for CT data
5cm above and below
important factors in CT scanning?
patient reproducible
errors will be carried forward
contrast can aid target delineation
what are the common files used to transfer CT data
DICOM-digital imagine and communications in medicine
transfer RT structures, doses and treatment parameters
file format of DICOM?
coordinates
patient must have correct orientation
supine or prone
XYZ coordinates
what factors affect isocentre position?
PTV location
PTV size and shape
what factors affect beam arrangements?
Ptv location, shape, size
structure in beam
OAR location beam energy and dose limits
external contour shape
what are some specialised planning systems?
Multiplan
Tomotherapy
important aspects of TPS
Acquisition of DICOMs 3d dataset display Model different linacs parameters 3d calculation of dose evaluation tools export DICOM
inside the TPS box?
patient and beam model
dose calculation
what is there treatment planning process?
register patient in TPS import patient data setup coordinates identify volumes add beams prescribe radiation therapy calculate dose distribution optimise plan QA
what 3d data can be imported?
Elekta, Philips, Siemens, Toshiba
MR/PET datasets
why is it important to scroll through CT slices?
find fiducial markers/BBs
understand CT dataset orientation
what is the common dose grid resolution for 3DCRT?
0.3-0.4
IMRT/VMAT dose grid resolution?
0.2-0.25
what is a treatment couch made of?
carbon firbre
foam core
metal components
types of couches?
Varian
Elekta
other inserts
what is an appropriate laser localisation?
where vertical and transverse lines traverse the 3 BBs for pelvis patient
what external devices can effect dosimetry?
couch tops immobilisation equipment
can increase surface dose due to attenuation
what are two approaches involving couch tops in TPS?
integrate a CT scan of treatment couch
Couch removal tool (pinnacle)
how can CT couches be included?
Assign CT numbers
