Dr. Arjun Sahgal is an international clinical and research leader in the field of high precision stereotactic radiation to the brain and spine for both metastases and primary tumors. After training at the University of Toronto in radiation oncology, he completed a radiosurgery fellowship at the University of California San Francisco. He has published, as lead or as a contributor, over 400 peer reviewed papers including in high impact journals like the Journal of Clinical Oncology, Lancet Oncology, and New England Journal of Medicine. He developed the 24 Gy in 2 SBRT fraction regimen for spinal metastases which was tested in the landmark SC24 randomized trial, proving superiority over conventional palliative radiation with respect to complete pain response. He currently leads the Sunnybrook Odette CNS Neuro-Oncology program that has been awarded a total of $42.5 M in funding since his leadership. Currently, he serves as Deputy Chief of the Department of Radiation Oncology at the University of Toronto affiliated Sunnybrook Odette Cancer Centre. In addition, he is the director of the Sunnybrook Cancer Ablation Therapy (CAT) program which involved the installation of a MR Brachytherapy suite, MR Linac and Gamma Knife Icon technology. His next phase of research is in the development of MR in radiation therapy, and the application of MR Guided Focused Ultrasound Technology with radiation. Key words: Radiosurgery, stereotactic body radiotherapy, brain tumors, spine tumors, brain metastases, spine metastases, oligometastases, MR image guidance, image guided radiotherapy, MR Linac, Gamma Knife