COG-SRS is a radiosurgical planning approach that selectively reduces dose to cognition-critical structures while maintaining target coverage and respecting all standard safety constraints.
Pre-Planning Imaging & Data
- Baseline MRI: High resolution T1w pre/post contrast, T2/FLAIR, DTI (for tractography), and optional perfusion/ASL.
- MR quality checks: Appropriate management of motion, gradient nonlinearities, bias fields, eddy currents, and B0 inhomogeneities.
- Planning CT: Standard immobilization and simulation procedures.
- Registration: Rigid registration of MRI → CT with QA checks.
Structure Identification
- Targets: GTV/CTV/PTV per institutional policy and pathology.
- OARs: Key cognition-related structures include the hippocampi and eloquent white matter tracts linked to specific cognitive domains. These structures can be prioritized based on tumor location. Standard OARs are also included per institutional guidelines.
- Derivation: Automated segmentation incorporates DTI-based tractography of major white matter tracts as well as subcortical nuclei, including the hippocampi. All results undergo neuroradiology review to ensure accuracy.
Planning & Optimization
- Technique: The example plans displayed on this site were created for frameless, linac-based SRS. COG-SRS can also be implemented with other radiosurgical platforms.
- Prioritization: PTV coverage and standard OAR constraints are addressed first in accordance with institutional policy, followed by targeted dose reductions to cognition-critical structures.
- Iterate: DVH-guided replanning for optimization.