Figure 2: The curves depict the total number of GBM cells for one patient for eight values of 𝑎 ranging from 0 (no effect of radiotherapy) to 0.021 G y 1 after applying the diffusive model. The same plot shows the three different points of real cell numbers, estimated after segmenting the tumors on three MRI datasets on the respective days. The optimal value of 𝑎 lies around 0.006 G y 1 .