This research study is for Glioblastoma (GBM) patients who will be beginning Optune as part of their clinical care, which is a novel treatment that utilizes - tumor treating fields (TTFields), (aka, electrical therapy), which has shown to improve overall survival in large multi-center trials. As a part of this study, participants will either receive Optune with "standard array mapping" (based on regular contrast enhanced MRI) or an "alternative (more precise) array mapping" based on sophisticated state of the art MRI techniques including "whole brain spectroscopy". Whole brain MRI spectroscopy provides additional metabolic information to map out the full extent of tumor spreading within the brain (far beyond from what is seen on regular MRI), by identifying certain metabolites that are present in cancer cells versus healthy tissue. This study is being performed to show whether alternative array mapping improves treatment outcomes, as opposed to the standard array mapping, by maximizing delivery of TTFields dose, thereby achieving more effective tumor cell killing, decreasing the rate of local recurrence, and improving the overall survival as well as quality of life measures.

Inclusion Criteria:

• Adult population ≥ 22 years
• Histologically confirmed diagnosis of GBM or molecular GBM according to c-IMPACT NOW criteria
• Have undergone maximal safe surgical resection followed by either standard full course radiation of 6000 cGy in 6 weeks or a hypofractionated course of 4000 cGy in 3 weeks
• 3 Harboring any genotype profiles (MGMT promoter methylation or unmethylation and/or isocitrate dehydrogenase (IDH) mutant or IDH wild-type)
• Possessing adequate hematological, hepatic and renal functions
• Willingness to receive TTFields

Exclusion Criteria:

• Presence of infra-tentorial GBM
• Pregnancy
• Significant co-morbidities at baseline which would prevent maintenance TMZ treatment
• Active implanted medical device, a skull defect (such as missing bone with no replacement) or bullet fragments. Examples of active electronic devices include deep brain stimulators, spinal cord stimulators, vagus nerve stimulators,pacemakers, defibrillators and programmable shunts. , other implanted electronic devices in the brain.
• Sensitivity to conductive hydrogels like the gel used on electrocardiogram (ECG) stickers or transcutaneous electrical nerve stimulation (TENS) electrodes.
• Presence of significant hemorrhage in and around the tumor bed that may potentially degrade the image quality.