Figure 4

Technique A (Semi-automated Software Prototype for CT 3d Rendering with the “Chebyshev Center Concept” implemented) - Image Example. A-D Axial image plane (A) and sagittal image plane (B) as well as corresponding volume rendering (C, D) – IRE Protocol 2. E-H Axial image plane (E) and coronal image plane (F) as well as corresponding volume rendering (G, H) – IRE Protocol 3. Note: after manual segmentation of the treatment zone (green), long, intermediate and short diameter (LCD, ICD and SCD) as well as the largest inscribed sphere within the treatment zone (yellow) and the largest possible treatable tumor sphere (black) were defined automatically (in Figure 4E, SCD is not indicated since its craniocaudal course). The barycenter offset is the distance between the barycenter of the treatment zone (intersection point of long, intermediate and short diameter) and the “Chebyshev Center” (center of the largest inscribed sphere within the treatment zone = center of the largest possible treatable tumor sphere). Observe the conspicuous eccentricity of the “Chebyshev Center” within the treatment zone (which is quantified by the barycenter offset) on standard image planes (B and E) which is not assessable with standard CT 3d analysis (Figure 5). Visualization and quantification of size and position of the largest inscribed sphere within the treatment zone (as well as of the largest possible treatable tumor sphere) can be relevant for acute treatment control after IRE (e.g. confirmation of the intended safety margin size).