## 1 Introduction
Another important statistical finding is that the 5-year survival rate for patients who suffer from these types of cancer is nearly 36%, while the 10-year survival rate is almost 31%, which decreases with increasing age. At younger ages, i.e., for populations between fifteen to thirty-nine years old, the 5-year survival rate is almost 71%. The 5-year survival rate for people over forty years old drops to 21%. However, survival rates are dependent on several factors, such as genetic, environmental, immunological, biochemical, and biological factors, including the location and kind of spinal cord or brain tumor. For instance, environmentalconditions are considered as potential risk factors for carcinogenesis of brain tumors by means of radiation exposure, poisonous agents (N-nitroos composites, plant protection products), atmospheric pollution, and electromagnetic radiation through radio waves. However, for certain contributing factors, there is no definite scientific evidence to advocate their correlation. On the other hand, 5% of cerebral tumors are linked to various hereditary cancer predisposition syndromes. People with these disorders inherit a germline mutation in a tumor suppressor gene. Although the relationship between hereditary genetic factors and brain tumors has been established, greater efforts should be focused on identifying the underlying genes. Finally, immunological, biological, and biochemical factors such as exposure to infections, viruses, and allergens, may be among the risk factors for developing brain tumors, although more studies validating such hypotheses are imperative [3]. Glioblastoma multiforme (GBM) is the most frequent and aggressive malignant primary brain tumor in people over 18 years old and is classified, together with other types of tumors, in the general class of gliomas. Several studies demonstrate that more complete resection of these tumors leads to improved outcomes for patients [4, 5, 6, 7], and, thus, many approaches are being implemented to improve the extent of tumor resection. In clinical trials, [PERSON] and coworkers [8] have demonstrated that image-guided resection of GBM results in more accurate removal of tumorous tissue, as well as higher survival rates and improved living standards for patients. The first in vivo trials for image-guided surgery in GBM using an administered probe were performed by the group of [PERSON] [9, 10], indicating that multispectral optical methodologies achieve high-resolution quantitative imaging of tissue and cancer biomarkers. Similarly, the work of [PERSON] [11] supports the potential benefits of intra-operative optical imaging, showing that the use of fluorescence imaging achieves certain and case-sensitive detection of tumor tissue in real-time mode during surgery, enabling the detection of remarkably increased malignant lesions compared to those that could have been detected by visual observation. [PERSON] et al. [12] used animal models of GBM, which demonstrated that imaging probes can be added topically to the resection cavity and elaborate the tumor margin. The majority of the non-invasive near-infrared fluorescent (NIRF) imaging probes constructed so far are based on a consensus sequence of peptides to operate/behave as an enzyme substrate that enables probe activation. [PERSON] and her team [12] utilized fluorescently quenched activity-based probes (ABP), built on tiny molecule suicide inhibitors of tumor-associated proteases. Several studies emphasized the efficiency and utilization of NIRF probes. They proposed this particular topology for the detection of overexpressed tumor-associated markers [13] and the imaging of tumor-expressed proteases in tissue culture, as well as in tumors that were hypocormically implanted in mice [14]. The main contribution of this study is the application of tumor-margin identification for enhanced and user-friendly visual inspection of brain tissue along with efficient guidance of tumor removal.