3D/2D Image Registration for Patient Positioning in Stereotactic Radiosurgery

Abstract: In the application of stereotactic radiosurgery for treatment of brain tumors it is imperative that patients are positioned with sub-millimetre accuracy so as to not damage surrounding healthy tissue during treatment. We investigate how feasible the technique of digitally reconstructed radiographs is as a registration method for patient positioning in this type of high-accuracy application. In particular, since most registration methods based on said technique only rely on two simultaneous projection angles seldom reaching high enough accuracy, we consider any arbitrary amount and observe its effects on the registration accuracy. Three different approaches are considered for how multiple projections can be combined into one single metric. The results seem to indicate that although computed tomography yields accuracies well within the boundaries for stereotactic radiosurgery, cone beam computed tomography in its current state does not. Possible reasons explaining the difference include problems with reconstruction artifacts in the model and inadequate metrics.