Fig. (6) Accuracy comparison of boundary extraction algorithms, (a1-a3) segmentation to clusters; (b1-b3) region of tumor extracted by the Ncut; (c1-c3) boundary extracted by the proposed method, the local fitting of boundary in (b1-b3); (d1-d3) boundary extracted by the LFAC; (e1-e3) boundary extracted by the RFAC only.