This observational study aims to evaluate the effectiveness of magnetoencephalography (MEG) in the preoperative assessment of pediatric brain tumors, particularly in determining the extent of resection, and compare it with computed tomography (CT) and magnetic resonance imaging (MRI). The main questions this study aims to answer are: What is the consistency between MEG and CT/MRI in localizing pediatric brain tumors? What is the clinical efficacy of MEG in determining the extent of resection of pediatric brain tumors preoperatively? Participants will: Undergo both MEG and CT/MRI examinations for preoperative assessment, and the extent of tumor resection will be determined by the comprehensive results of the above examinations. Be followed up with MEG and CT/MRI at 1, 3, and 6 months after surgery, along with neurological and quality-of-life assessments.