Arjun Sahgal works in the field of high-precision stereotactic radiation to the brain and spine. After training at the University of Toronto (ON, Canada) in radiation oncology, he completed a fellowship at the University of California, San Francisco (CA, USA) in brain and spine radiosurgery with Professor David Larson. Since then, he has been recognized as a national and international clinical expert and research leader in radiosurgery. His main focus is on developing spine stereotactic body radiotherapy (SBRT), also known as spine radiosurgery, as an effective therapy for patients with spinal tumors. Research achievements include publishing spinal cord tolerance guidelines for spine SBRT as part of an international multi-institutional effort. This work elucidated safe dose limits for the spinal cord specific to spine SBRT, and was the first of its kind. He has developed the spine SBRT program for the University of Toronto and is conducting the first Phase II clinical study on spine SBRT for metastases in Canada. He has also recently written national guidelines on behalf of the Canadian Association of Radiation Oncology (CARO) for the practice of spine, lung and liver SBRT, and continues to lead national and international multi-institutional groups dedicated to spine and brain radiosurgery research.