Purpose: Hippocampal avoidance during whole-brain radiotherapy (HA-WBRT) presents significant technical challenges in contouring and treatment planning. This study explores the feasibility and efficacy of hippocampal sparing using LINAC-based RapidArc techniques for patients with brain metastases.
Materials/Methods: Ten anonymized patients treated with HA-WBRT were analysed. The hippocampus was contoured, and hippocampal avoidance regions were created using a 5 mm volumetric expansion. RapidArc plans were generated for a prescription dose of 30 Gy in 10 fractions.
Results: The LINAC-based RapidArc plans achieved significant hippocampal sparing, with a D100 of 8.12 ± 0.02 Gy and a maximum dose of 12.04 ± 0.44 Gy. The mean dose to the hippocampus was reduced by 81% to 0.98 Gy per fraction. Target coverage and homogeneity were maintained within acceptable limits.
Conclusion: Modern IMRT/RapidArc techniques enable effective hippocampal sparing while preserving target coverage and homogeneity. These findings support the clinical implementation of HA-WBRT to mitigate neurocognitive decline in patients with brain metastases.