The Glioblastoma Multiforme (GBM) is a type of malignant and very
aggressive brain tumor. For this reason, computational tools to support the
GBM study are of great interest to the field of biomedical research. This paper
describes the construction of an image marker software based on image pro-
cessing for to assist the user in the graphical segmentation of the region of the
tumor in the image. The development of the program presented here was super-
vised by medical specialist and its use was essential to start the simulation of
the evolution of the GBM undergoing treatment with the drug bevacizumab.