Rationale: Visualization of tumor spread is of crucial importance when treating patients suffering from glioblastoma (GBM) as the success of tumor resection depends strongly on the extent of tumor infiltration. Current MRI protocols, however, cannot visualize the extent the tumor infiltration. The use of non-toxic, non-dangerous ultrasmall superparamagnetic biodegradable iron oxide (USPIO) particles as a very strong blood pool contrast agent could help visualizing this invisible infiltration Objective: To what extent, do GBMs infiltrate healthy brain tissue and can we use ultrasmall superparamagnetic iron oxide particles to visualize co-opting infiltrating tumor cells in an attempt to predict regions of tumor recurrence? Study design: This study concerns a single arm prospective observational study. Study population: Patients diagnosed with suspected glioblastoma. Intervention (if applicable): USPIO neuroimaging Main study parameters/endpoints: The main parameter of this study concerns the feasibility of using of USPIO particles in healthy controls (n=6) and glioblastoma patients (n=15).

Nature and extent of the burden and risks associated with participation, benefit and group relatedness: During this study patients will be intravenously injected with low doses of USPIOs. Risks involved with this procedure include: bruising of the skin after venapunction and allergic reaction to USPIO particles.

The application of USPIO neuroimaging can improve diagnosis of patients with suspected glioblastoma, provide more information on the pathophysiology of growth of glioblastoma lesiosn, the role of neuro-inflammation in these lesions and maybe predict regions of tumor recurrence after treatment.

Inclusion Criteria:

• Aged between 18 and 75 years
• Diagnosed with suspected glioblastoma
• Eligible for neurosurgical resection and/or chemoradiation therapy.

Exclusion Criteria:

• Younger than 18 years old
• Patients unfit for surgery or lesions unsuitable for neurosurgical treatment

Clinicians will recruit men and women diagnosed with a suspected glioblastoma who are scheduled to undergo neurosurgical resection and/or chemoradiation therapy as treatment.