[Place of Linacs in extracranial stereotactic radiotherapy: Are they now equivalent to Cyberknife®?]

Abstract

Extracranial stereotactic radiotherapy has developed recently, since the years 1990-2000. Devices specifically dedicated to this type of treatment were then developed and shared the favors of radiation oncologists: Tomotherapy® and especially Cyberknife®, which offered the advantage of "tracking" with the possibility of real time motion correction, allowing an increase in the precision of targeting volumes. Recently, the latest generations of linear accelerators (Linac) have been developed, integrating much higher dose rates, an improved ballistic precision with a very short treatment duration time and the possibility of real time motion management (with notably the possibility of adaptive radiotherapy in real time with the development of "MLC tracking"). So are Linacs able to perform equivalent (not inferior) extracranial stereotactic radiotherapy treatments to those with Cyberknife®, the historical gold standard in this field? This article presents a comparison of these two treatment devices, by successively considering dose distributions in the irradiated volume, distant received doses from this volume (including the "integral dose"), problems linked to the duration of the sessions and those linked to motion management.

Keywords: Comparaison; Comparison; Cyberknife®; Extra-crânienne; Extracranial; Linac; Radiothérapie stéréotaxique; Stereotactic radiotherapy.