Introduction to Treatment Planning Principles Flashcards
what is the aim of treatment planning
irradiate the target volume with the dose prescribed
reduce the dose to normal tissue as much as possible
create the optimal dose distribution
what is isocentric treatment
all beams have a common focal point which is the isocentre
all beams are attached to the same isocentre
FSD of each beam varies depending on the patient contour
what is fixed treatment
same FSD for all beams
FSD is the same for all beams as you ‘fix’ this (usually 100cm)
what is field size defined as in an FSD field
field size is defined at the surface of the phantom/patient
what is field size defined as in isocentric technique
field size is defined at the isocentre
what are beams named by
their gantry angle anatomical orientation
what is an isodose curve
an isodose curve is a curve passing through points of equal dose
what is penumbra
penumbra is often defined as the 20% and 80% isodose lines
penumbra is the region near the edge of the field where the dose falls off rapidly
what is the purpose of a wedge
to shape the isodose distribution
what is a bolus
a tissue equivalent material placed directly on the surface of the skin
what is the purpose of bolus
to increase the dose on the surface
