Brachytherapy; Brain Neoplasms/radiotherapy; Cranial Irradiation; Glioblastoma/radiotherapy; Iridium Radioisotopes/therapeutic use; Neoplasm Recurrence, Local/diagnostic imaging; Postoperative Complications/diagnostic imaging; Tomography, Emission-Computed, Single-Photon; Adult; Aged; Brain/diagnostic imaging; Brain/radiation effects; Brain Neoplasms/diagnostic imaging; Brain Neoplasms/mortality; Brain Neoplasms/surgery; Carbon Radioisotopes; Combined Modality Therapy; Diagnosis, Differential; Disease-Free Survival; Female; Follow-Up Studies; Glioblastoma/diagnostic imaging; Glioblastoma/mortality; Glioblastoma/surgery; Humans; Iridium Radioisotopes/adverse effects; Male; Middle Aged; Neoplasm Recurrence, Local/surgery; Positron-Emission Tomography; Postoperative Complications/surgery; Radiation Injuries/diagnostic imaging; Radiotherapy, Adjuvant; Reoperation; Sensitivity and Specificity; Thallium Radioisotopes; Tyrosine