This is a prospective observational study. Patients with suspected brain tumors requiring 5-ALA fluorescence-guided surgery will be enrolled. Samples of plasma, serum, and urine will be collected at a minimum of two timepoints: once before 5-ALA administration (baseline, T1) and again 12 hours after administration (T2), when PpIX levels are expected to be highest. All sample collection and processing will occur in low-light conditions to prevent PpIX degradation. Samples will be stored at -80°C. Fluorometric analysis (Perkin Elmer Wallac 1420 Victor2 Microplate Reader) will be performed to measure PpIX fluorescence. Additionally, each patient will undergo a pre-operative MRI as per routine care to measure tumor volume, which will be correlated with fluorescence data.
