Advanced
radiotherapy techniques enable highly conformal dose distribution to
the tumor. This higher precision is made at the cost of an increased
healthy tissue volume receiving low doses which may lead to mid and
long-term adverse effects. Risk assessment requires a precise knowledge
of the doses delivered to healthy tissues. However, these doses are
still unknown as calculated incorrectly by the treatment planning
systems (TPS).
Within
this context, this thesis aims at precisely determining the doses
delivered to normal tissues by advanced radiotherapy techniques. Thus,
numerical and experimental tools have been developed and implemented.
The Monte-Carlo model of a CyberKnife system developed in this work
allows for the determination of accurate input data for risk models.
Experimental developments have been used to compare the doses delivered
by three radiotherapy techniques (conformational, VMAT and tomotherapy)
in a pediatric renal treatment. While advanced techniques deliver highly
conformal dose distribution, the doses to organs located at distance
from the target are considerably increased up to a factor 3 in
comparison with conformal radiotherapy. Finally, thanks to these
developments, TPS capabilities have been assessed.