Fig 3.

Delineation of the radiation therapy target for the treatment of a gross totally resected GBM in the right temporal lobe and its relation to tumor recurrence. A, Fused planning CT and axial contrast-enhanced T1-weighted postoperative image allow visualization of the radiation dose effectively delivered in the brain parenchyma adjacent to the surgical cavity (isodose chart). The high-dose region is defined as the area inside the pink line, corresponding to the 100% isodose line (60 Gy) plus the area between the pink and green lines, corresponding to the 80% isodose line (48 Gy). B, Fused planning CT and axial contrast-enhanced T1-weighted follow-up images demonstrate that a significant portion of the new enhancing lesion was located outside the high-dose radiation field (inside the green line), which is consistent with progressive disease.