Figure 2.

Examples of SR-surgery. Panel A shows 3 examples of SR-surgery configurations illustrated with 3D reconstructions of the skull surface based on CT scans. Four burr holes of 15 mm diameter were used in the leftmost example, 7 burr holes of 18 mm diameter in the middle example, and a total elliptic craniectomy of 85 × 65 mm semi-axes in the rightmost example, respectively. In all cases, the skull defects were distributed above the resection cavity and its surrounding borders, as shown in panel B for the leftmost case in panel A. The representation in panel B generally shows the skull and tumor outline in the computational model for the (courtesy of Novocure, Ltd) with the skull surface shown in purple, the craniotomy bone flap in red (primary surgery) and dark red (repeated surgery), the craniotomy line in pink, the underlying tumor in blue, and the resection cavity in green. The transducer array layout is shown in the rightmost illustration in panel B with orange markings on the A/P pair. Panel C shows surface reconstructions of the field distribution before (left) and after (right) SR-surgery for the same patient. Parts of the figure are reproduced from Ref. ²². Panel D shows the difference in current density distribution before and after SR-surgery equivalent to the case in panels A (left), B, and C. Results are shown for the skin (left) and CSF (middle) surfaces, respectively, and for the L/R array pair only. It is evident, that a significant amount of current is shunted through the burr holes. The rightmost illustration in panel D shows the equivalent absolute difference in field distribution in the underlying brain. Finally, panel E shows the relationship between the total area of the skull defect for the individual SR-surgery configurations (cm²) and the corresponding relative field enhancement (%). Patients treated with TTFields (n = 11) are shown in blue and patients excluded prior to TTFields (n = 4) are shown in red.