[Progress in dosage optimization for stereotactic radiosurgery].

Stereotactic radiosurgery is a technique for treatment of intracranial lesions requiring high precision in all steps--from image acquisition to final irradiation. One of most difficult steps is the treatment planning phase, consisting of determination of irradiation parameters sufficient to cover the target volume by avoiding sensitive volumes. A manual and empirical definition can be very long and difficult, especially in the case of complex target volumes situated in sensitive zones.