Assessment of Early Post-operative Nuclear Imaging in Neurosurgery: a Safety and Feasibility Study in Patients Operated for Glioblastoma

This study aims to assess safety and feasibility of early post-operative PET-MRI and validate imaging parameters for detecting glioblastoma residue, enabling future personalized post-surgical care.

The primary objectives are to :

* Asses the safety of performing early post-operative brain PET-MRI in neurosurgery patients after glioblastoma surgery. * Measure the nuclear exposition of patients when performing early post-operative brain PET-MRI in neurosurgery patients. * Assess the feasibility of performing early post-operative brain PET-MRI in neurosurgery patients.

It is a prospective interventional diagnostic study involving patient comparison Category RIPH. 15 patients will be included. This is a monocentric study. One surgical and including site (CHU Henri Mondor), in one country (France).

Patients will participate during 24 hours. The duration of the study is 12 months.

Following gadolinium injection, patients will be monitored for at least 30 minutes to allow for the early detection of potential side effects. Immediate hypersensitivity reactions, including anaphylactoid responses or other idiosyncratic effects, may present with cardiovascular, respiratory, or cutaneous symptoms, and can be severe.

Although delayed reactions are rare, most immediate events occur within the first 30 minutes post-administration. Monitoring is routinely implemented in clinical practice and will be applied accordingly in the study.

18F-DOPA injection can induce pain at the injection site, probably due to the acidity of the product. Given the minimal quantity of substance administered, the primary risk is associated with the exposure to ionizing radiation. In theory, such exposure may induce carcinogenesis or result in the development of hereditary defects. Nevertheless, since the effective dose is approximately 7 mSv and we are well below the maximum recommended activity of 280 MBq, the probability of these adverse effects occurring is considered very low.

2\. MRI

1. Diffusion B1500 2. SWI 3. 3D FLAIR 4. 3D T1 SPACE 5. ASL 6. Spectroscopy (TE short et TE long) in the tumoral surroundings 7. After gadolinium injection : Perfusion T2\*, Angio-MRI, 3DT1 SPACE

For PET-MRI imaging, tracer administration and acquisition timing will follow standard clinical protocols. For 18F-DOPA, a static brain acquisition will be performed between 10- and 30-minutes post-injection, as recommended for glioma imaging.

Study design is as follow :

• Pre-surgical baseline evaluation: 30 days - 2 days prior to surgery

* Patient information * Medical History and Treatment, clinical assessment * Preoperative Brain MRI and PET-MRI as detailed hereabove.

Patients usually undergo preoperative brain PET-MRI with gadolinium enhancement and 18F-DOPA injection as a standard of care. No specific period of time will be necessary to schedule the surgery after this imaging.

* D0: Neurosurgical procedure for tumor resection, as decided by the neurosurgeon, under general anesthesia * Between D0 post-surgery and D2: patient informed consent and inclusion

* H0: Patient informed consent and inclusion * Baseline medical examination * Patient transferred to the nuclear medicine department * Positioning of a dosimeter * Radiotracer intravenous injection * For suspected glioblastoma:

18F-Dopa 2MBq/kg, starting the imaging immediately after injection * Postoperative brain PET-MRI acquisition * Surveillance time in nuclear medicine according to standard procedures * Patient transferred back to the neurosurgery department * Surveillance time: 24 hours dosimetry measurements * End of inclusion medical examination * Removing the dosimeter * H24: End of patient inclusion Neurosurgical follow-up and home discharge as established by the referent per clinical practice.

No medicinal product with therapeutic intent are administered in this study, only imaging agents usually used in clinical practice for diagnostic purposes are employed. The remainder of the patient's care will be managed according to the standard of care.

Only diagnostic imaging agents routinely used in standard clinical neuroimaging protocols will be administered during the study.

Gadolinium-based contrast agents will be used for MRI sequences requiring enhancement.

For PET imaging, 18F-DOPA will be employed. All imaging agents will be used under standard clinical conditions, in accordance with current safety and administration guidelines.

• Validate a nuclear imaging protocol to measure residual tumor volume on early post-operative brain PET-MRI in neurosurgery patients [Time frame: 24 hours]
• Evaluate the inter-raters reliability of nuclear imaging protocol (T/S and T/CC) to evaluate the presence or absence of residual tumor on early post-operative brain PET in neurosurgery patients. [Time frame: 24 hours]
• Evaluate the inter-raters reliability of nuclear imaging protocol (metabolic volume with different thresholds) to measure residual tumor volume on early post-operative brain PET in neurosurgery patients. [Time frame: 24 hours]
• Validate a nuclear imaging protocol to measure residual tumor volume on early post-operative brain PET-MRI in neurosurgery patients [Time frame: 24 hours]
• Validate a nuclear imaging protocol to measure residual tumor volume on early post-operative brain PET-MRI in neurosurgery patients [Time frame: 24 hours]
• Validate a nuclear imaging protocol to measure residual tumor volume on early post-operative brain PET-MRI in neurosurgery patients [Time frame: 24 hours]
• Validate a nuclear imaging protocol to measure residual tumor volume on early post-operative brain PET-MRI in neurosurgery patients [Time frame: 24 hours]
• Validate a nuclear imaging protocol to measure residual tumor volume on early post-operative brain PET-MRI in neurosurgery patients [Time frame: 24 hours]