Radiology Considerations for Radiosurgery

Neuroimaging plays a pivotal role in management of intracranial lesions using stereotactic radiosurgery (SRS) or stereotactic radiotherapy (SRT). Among the available imaging modalities, high-resolution magnetic resonance imaging (MRI) serves as the workhorse for SRS assessment. Computed tomography (CT), positron emission tomography/ computed tomography (PET/CT), and catheter angiography play complementary roles. Pretreatment neuroimaging is important for delineating lesion size and extent, identifying critical neighboring structures and prognostic biomarkers, and for treatment planning. Post-treatment imaging is essential to monitor treatment response, recognize pseudo progression and complications, and for long-term follow-up of residual tumor and other radiosurgical targets. Imaging protocol recommendations, imaging biomarkers and pitfalls, and selected complications are discussed in the subsequent relevant sections.