Source
Gamma Knife Center, Erasme University Hospital, Brussels, Belgium. nmassage@ulb.ac.be
Abstract
INTRODUCTION:
The role of radiation dose delivered to surrounding tissues outside target is often minimized in radiosurgery. We study histopathological effects of dose fall-offs outside the target using an experimental model of trigeminal nerve irradiation in the rat.
MATERIAL AND METHODS:
Sixteen rats were irradiated with a Gamma Knife at the right trigeminal nerve using a 90-Gy dose and 4 different gradients of dose fall-off; the brainstem at the trigeminal nerve root entry was histologically analyzed 3 months after irradiation.
RESULTS:
Four specific histopathological reactions were found as a consequence of the irradiation. All these reactions were significantly related to the gradient of dose fall-off.
CONCLUSIONS:
Different dose distributions outside the target could produce various histological effects in the irradiated tissue that could influence the outcome of radiosurgical treatment. A more rapid fall-off of dose (higher selectivity) is associated with less risk of histological changes in tissues surrounding the target.
2009 S. Karger AG, Basel.