Abstract During CT-guided thermal ablation of lung tumors, guidelines define the intraprocedural endpoint as a circumferential margin of increased attenuation extending 5–10 mm beyond the tumor. This criterion does not require the strict radiologic texture of ground-glass opacity. The timely appearance of this margin is the main real-time marker of an adequate treatment volume, and its absence is conventionally read as underablation, prompting additional energy delivery.
