L0_2016_Athens_Physics_Programme

Interplay - Dynamic techniques

Problem

: planning for IMRT, dynamic arc treatment or active scanning particle

therapy on a moving target

→

the motion of the target may

interfere

constructively or destructively with the

motion of the MLC leaves, the beam opening, the gantry rotation, the beam scan path

and

or other dynamic parameters during treatment delivery.

→

The effect of such interferences is that the dose to sub-volumes in the patient may be

significantly different from the planned dose, since

interferences are not modeled

in the treatment planning system.

Solution

: it has been demonstrated that if an IMRT plan is delivered in multiple

fractions over the course of treatment the relative cumulative error could be small,

but

… when is motion mitigation required??