Figure 1From: A retrospective, deformable registration analysis of the impact of PET-CT planning on patterns of failure in stereotactic body radiation therapy for recurrent head and neck cancerExamples of categories of failure. Pre-treatment scans (left) are fused to post-treatment scans demonstrating recurrence (right). Recurrent tumors are contoured, compared to deformed PTVs (red), and categorized. A–In-field (blue) and regional (yellow) failure. B–Overlap failures (blue, yellow). C–Marginal failure (blue).Back to article page