The goal of this clinical trial is to evaluate the safety and feasibility of focused ultrasound (FUS)-mediated blood-brain barrier (BBB) disruption using the Next Generation Dome Helmet (NGDH) in adults with glioblastoma (GBM) undergoing the maintenance phase of the standard "Stupp protocol".
Participants will:
* Undergo repeated FUS BBB disruption treatments during the maintenance phase of temozolomide (TMZ) chemotherapy.
* Receive intravenous ultrasound contrast (DEFINITY®) prior to each FUS session to facilitate targeted BBB disruption.
* Undergo serial MRI scans and clinical assessments to evaluate safety and the extent of BBB opening.
* Provide blood samples (and tumor tissue if available) for biomarker analysis related to BBB permeability, tumor presence, and treatment response.
* Be followed for progression-free survival (PFS) and overall survival (OS) during routine neuro-oncology visits until end of life.