1. Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA;
2. Gamma Knife Center Cairo, Nasser Institute Hospital, Cairo, Egypt;
3. Neurosurgery Department, Benha University, Qalubya, Egypt;
4. Neurosurgery Department, Ain Shams University, Cairo, Egypt;
5. Clinical Oncology Department, Ain Shams University, Cairo, Egypt;
6. Radiation Oncology Department, National Cancer Institute, Cairo University, Cairo, Egypt;
7. Department of Neurosurgery, Koc University School of Medicine, Istanbul, Turkey;
8. Department of Neurosurgery, Neurological Institute, Taipei Veteran General Hospital, Taipei, Taiwan;
9. School of Medicine, National Yang-Ming University, Taipei, Taiwan;
10. Department of Neurosurgery, Université de Sherbrooke, Centre de recherche du CHUS, Sherbrooke, Quebec, Canada;
11. Department of Neurosurgery, Post Graduate Institute of Medical Education and Research, Chandigarh, India;
12. Department of Neurological Surgery, University of Virginia, Charlottesville, Virginia, USA;
13. Stereotactic and Radiation Neurosurgery, Na Homolce Hospital, Prague, Czech Republic;
14. Department of Neurosurgery, University of Alberta, Edmonton, Canada;
15. Department of Neurosurgery, Allegheny Health Network, Pittsburgh, Pennsylvania, USA;
16. Division of Radiation Oncology, Allegheny Health Network Cancer Institute, Allegheny Health Network, Pittsburgh, Pennsylvania, USA