Board of Directors
Iris C. Gibbs

Iris C. Gibbs, MD, FACR, FASTRO


Dr. Iris Gibbs is a Professor of Radiation Oncology and Associate Dean of MD Admissions at Stanford Medicine, where her clinical and research expertise are pediatric and adult brain tumors, and robotic radiosurgery. As former Co-Director of Stanford CyberKnife Radiosurgery program, Dr. Gibbs contributed to building world- renowned clinical programs for the innovative radiation treatment of central nervous system tumors and robotic radiosurgery. Dr. Gibbs has served as committee chair for RSS and is a dedicated member of the International Stereotactic Radiosurgery Society (ISRS).

In 2014, Dr. Gibbs was appointed as Associate Dean for Medical School Admissions of Stanford Medicine. She is a 2015 Hedwig van Ameringen Executive Leadership in Academic Medicine (ELAM) Fellow and a fellow of the American Society of Radiation Oncology, American College of Radiology, and Association for Women Radiologists. In addition to leadership service roles for Radiological Society of North America (RSNA), American Society of Radiation Oncology (ASTRO), and the American Board of Radiology (ABR), Dr. Gibbs is the immediate past chair of the Section on Radiology for the National Medical Association.

Dr. Gibbs joined the RSS Board of Directors in 2016. She served as President from 2019 - 2021 and assumed the role of chairwoman in 2021.

Najeeb Mohideen

Najeeb Mohideen, MD, FRCR, FASTRO, FACR


Dr. Najeeb Mohideen is a Radiation Oncologist at Northwest Community Hospital in Arlington Heights, Illinois. A champion for innovation, he is a recognized leader in the study and technological advancements of radiation oncology.

Dr. Mohideen completed his medical degree from the Armed Forces Medical College Pune, and Radiation Oncology residencies from the Royal College of Radiologists, London, UK and Loyola University Medical Center (LUMC), Maywood, IL. He joined the faculty of LUMC and was an Associate Professor in Radiation Oncology and Urology at Loyola prior to joining Northwest Community Hospital.

He holds many National leadership positions in Radiation Oncology. He has served on the Board of Directors of the American Society for Radiation Oncology (ASTRO) and has also chaired its Health Policy Council. He is currently Chair of the Radiation Oncology Economics Committee for the American College of Radiology and also chairs ASTRO’s Payment Reform Workgroup. He has served on the ASTRO Image Guided Radiotherapy Task Force and Brain Metastases Guideline Committee. He is also currently a member on the Medicare Evidence Development & Coverage Advisory Committee (MEDCAC). He is a Fellow of the American Society of Radiation Oncology and the American College of Radiology.

Since 2015, Dr. Mohideen has served on the Board of Directors of the Radiosurgery Society. He was Secretary from 2016 - 2021 and in April 2021, became President.

Michael Schulder

Michael Schulder, MD, FAANS


Dr. Michael Schulder is Vice Chair, Residency Program Director, and Professor of Neurosurgery at the Zucker School of Medicine at Hofstra/Northwell, where he also serves as the Director of the Brain Tumor Center, and the Co-Director of the Center for Radiosurgery and Stereotactic Radiation.

In practice for over 23, years, Dr. Schulder trained in SRS at the University of Florida and at the Brigham and Women's Hospital. His experience includes treating patients with the X-Knife, CyberKnife, Novalis, Varian, and Gamma Knife systems. A member of RSS since 2003, Dr. Schulder believes strongly that SRS programs and the entire field are best advanced by surgical specialists working together with radiation oncologists.

Dr. Schulder joined the RSS Board of Directors in 2015. In April 2021, he began his term as Secretary of the Board of Directors.

John J. Kresl



Dr. John Kresl is an internationally recognized expert in stereotactic radiosurgery and stereotactic body radiotherapy. Dr. Kresl is Certified by the American Board of Radiology in Radiation Oncology and his involvement in oncology research has led to two registered U.S. patents with Immtech, Inc. for novel methods of diagnosing and treating cancer.

Dr. John Kresl serves as the Medical Director of the Phoenix CyberKnife and Radiation Oncology Center and of the Department of Radiation Oncology at Banner University Medical Center-Phoenix. He joined ROCA in 1998 and served as Co-medical Director of the CyberKnife Program and Assistant Director for the Center for Thoracic Disease at St. Joseph’s Hospital & Medical Center and Barrow Neurological Institute in Phoenix, Arizona until 2008. Dr. Kresl maintains an active clinical practice in radiation oncology for all tumor sites and has developed additional expertise with stereotactic radiosurgery and stereotactic body radiotherapy in the areas of brain/central nervous system, gastrointestinal, head and neck, genitourinary and lung malignancies.

Dr. Kresl is a past chairman of American Society for Therapeutic Radiology and Oncology (ASTRO) Workforce Committee. Dr. Kresl has served as the principal investigator and co-investigator on clinical protocol investigations and has published over 150 abstracts, manuscripts, book chapters and textbooks related to the field of radiation oncology. A distinguished fellow of the American Society for Therapeutic Radiology and Oncology (FASTRO), American College of Radiation Oncology (FACRO), American College of Radiology (FACR) and American College of Cancer Specialists, he is included in the Best Doctors in America 2011-2018 and was named among “America’s Top Oncologists 2010-18” by the Consumer Research Council of America.

Stanley H. Benedict

Stanley H. Benedict, PhD, FAAPM, FACMP


Dr. Stanley Benedict received an MS in Radiological Health Physics from San Diego State University, PhD in Biomedical Physics from UCLA, and diplomat in Radiological Therapeutic Physics from the American Board of Radiology. He has served as Chief of Clinical Physics at Virginia Commonwealth University, Director of Clinical Physics at the University of Virginia, and is currently Professor and Vice Chair of Clinical Physics in the Department of Radiation Oncology at the University of California at Davis in Sacramento, California.

Dr. Benedict scholastic has over 100 scientific publications, book chapters, and proceedings, and over 200 abstracts and scientific presentations at international symposia. Dr. Benedict has been PI, co-PI, co-investigator, and collaborator on a wide array of public and privately funded clinical medical physics research, including projects involving image guided radiation therapy, stereotactic radiosurgery, and radiation biology.

Dr. Benedict was the Chair of the AAPM Task Group 101 on Stereotactic Body Radiation Therapy, and is one of the editors of the CRC Press book entitled, Stereotactic Radiosurgery and Stereotactic Body Radiation Therapy (2014). Stan joined the Board of Directors in April 2017, and is also serving on the RSS Physics Committee.

Shalom Kalnicki

Shalom Kalnicki, MD, FACRO, FASTRO

Dr. Shalom Kalnicki is Professor and Chairman of the Department of Radiation Oncology at Montefiore Medical Center and Albert Einstein College of Medicine. A physician, researcher and instructor, Dr. Kalnicki has led this internationally-recognized radiation oncology department since 2004.

Considered an innovator in the field, Dr. Kalnicki has pioneered research in the radiation treatment of cancer, including intensity-modulated radiation therapy, image-guided radiation therapy, target motion management with 4-D radiation planning, stereotactic body radiation therapy, and functional tumor imaging with PET-CT fusion techniques.

Dr. Kalnicki’s radiation oncology research has had implications for treating brain, head and neck, thoracic, upper abdominal and pelvic malignancies and includes quality-of-life issues such as socio-economic disparities and the impact of family caregiver support on patients’ compliance.

Dr. Kalnicki has served on the RSS Board of Directors since 2014. From 2017 - 2019 he served as President and from 2019 - 2021 as Chairman.

Percy Lee

Percy Lee, MD

Dr. Lee is Professor and Section Chief of the Thoracic Radiation Oncology Section in the Department of Radiation Oncology at The University of Texas M.D. Anderson Cancer Center. He is also the Associate Medical Director of the Thoracic Cancer Center. Prior to joining M.D. Anderson, Dr. Lee was Professor and Vice-Chair of Education for the Department of Radiation Oncology at UCLA. At UCLA, he served as Chief of Thoracic Radiation Oncology, Residency Training Program Director, and Director of the SBRT Program. Dr. Lee was the founding director of the SBRT program at UCLA and credited for building a patient-centered program of excellence that attracted patients from all over the U.S.

Dr. Lee has research interests in applying novel technologies such as MRI-guided radiation therapy in the clinic and led the clinical implementation of the MRI-guided radiation therapy program at UCLA as the 3rd site in the world with this innovation. He is a national PI for a number of cutting-edge trials using SBRT for thoracic and pancreatic cancer, some of which leverage the use of SBRT with novel immunotherapeutic agents. He has co-authored more than 150 peer-reviewed publications, many of them on the expanded role and evidence for SBRT in various clinical settings. He has served in various leadership roles within national organizations such as ASTRO, ABR, ARS, ACR, and RSS. With RSS, he has been an active member of the scientific meeting planning committee, invited for speaking and moderating roles at the scientific meetings as well as webinars. He believes that the RSS is a great conduit to wider adoption of radiosurgery in the community and fostering clinical and technical innovations to increase its reach. Dr. Lee joined the RSS BOD in April, 2021.

Simon S. Lo


Dr. Simon Lo is Professor and Vice-Chair of Strategic Planning and Professor of Neurological Surgery at the University of Washington Department of Radiation Oncology.

Dr. Lo has edited 4 comprehensive textbooks in SRS/SBRT and published 200+ full peer-reviewed papers, a majority of which center on SRS/SBRT for all body sites and has led the SBRT programs in 3 NCI-designated Comprehensive Cancer Centers. Dr. Lo currently serves on the 2019 RSS Annual Scientific Meeting Planning Committee and the Accreditation Committee as Medical Director and helps develop educational webinars for RSS.

Helen Shih

Helen Shih, MD, MS, MPH, FASTRO

Dr. Shih is an Associate Professor of Radiation Oncology at Harvard Medical School, Boston, MA. Helen is a practicing radiation oncologist at Massachusetts General Hospital (MGH). Prior to MGH, Dr. Shih did her undergraduate education at Brown University as a biology major and medical school education at the University of Pennsylvania where she also earned a Master's Degree in Cell & Molecular Biology. She completed a transitional year internship at Beaumont Hospital, Royal Oak, MI, before radiation oncology residency at MGH. She also has a Master's in Public Health from the Harvard School of Public Health. Dr. Shih has remained on staff at MGH and is the Director of the Central Nervous System & Eye Services. She specializes in the treatment of patients with brain and eye tumors. She cares for a range of patients with benign to malignant diagnoses and both primary and metastatic diseases. She is an Associate Professor of Radiation Oncology at Harvard Medical School and Medical Director of the MGH Proton Therapy Program. Dr. Shih joined the RSS Board of Directors in April 2020.

Shankar Siva

Shankar Siva, PhD, MBBS, FRANZCR

Dr. Siva is an Associate Professor Radiation Oncology, Peter Maccallum Cancer Centre, Victoria, Australia. Shankar is a Radiation Oncologist and NHMRC fellow at the Peter Mac and leads the Stereotactic Ablative Body Radiotherapy (SABR) program and Australia's first dedicated SABR clinic. He completed his PhD with the Molecular Radiation Biology (Martin) Laboratory focusing on translational investigations in precision high-dose lung radiotherapy. He published the first original research from Australia on the use of the SABR technique.

Shankar leads multiple clinical trials in the treatment of lung and urological cancers at the Peter Mac, and is chair of three TransTasman Radiation Oncology Group (TROG) studies in the fields of oligometastases, lung and kidney cancers. He is Co-Chair of the TROG Genitourinary Group, is an executive member of Radiation Oncology Research Committee (RORC) of the Royal Australian and New Zealand College of Radiologists (RANZCR) and Management Advisory Committee (MAC) of the Australasian Lung Cancer Trials Group (ALTG) amongst other leadership roles. He has research interests in high-tech radiotherapy delivery, radiation biology and radiation immunology. Dr. Siva joined the RSS Board of Directors in April 2020.

Ben J. Slotman

Ben J. Slotman, MD, PhD, FASTRO, H.FACR

Berend (Ben) J. Slotman, MD, PhD, FASTRO, H.FACR, Professor and Chairman of the departments of Radiation Oncology at Amsterdam Universiteit Medical Center and Vrije Universiteit Medical Center in Amsterdam, Netherlands. Since 1998, Ben Slotman has served as Professor and Head of the Department of Radiation Oncology at Vrije Universiteit medical center (VUmc) in Amsterdam, The Netherlands.

Dr. Slotman received his MD (1985) and PhD (1990) both with highest honor (cum laude) at VU University in Amsterdam, The Netherlands and he was registered as radiation oncologist in 1994. He also served as chairman of one of the six divisions of the VU academic center from 2006-2016. Since 2019, he is also the head of the department of Radiation Oncology at the Academic Medical Center (AMC) in Amsterdam. As the two university hospitals VUmc and AMC will merge into Amsterdam university medical centers, Ben Slotman’s task is to lead and unite the two academic departments.

Professor Slotman is the (co-)author of around 400 international peer-reviewed publications. His expertise lies mainly in the field of radiotherapy for lung and brain malignancies and the early clinical implementation of new technologies. He has (co-)organized many conferences and has coordinated a number of trials, including the EORTC study on prophylactic cranial irradiation in extensive stage small cell lung cancer (published in New Engl J Med 2007) and the international randomized trial on the role of thoracic irradiation in these patients (published in The Lancet 2017). His research activities are further concentrated on intra- and extracranial stereotactic radiotherapy and the introduction of various new technologies in radiotherapy, most recently being stereotactic MRI-guided adaptive radiotherapy. He is associate editor of the Journal of Radiosurgery and SBRT.

He was awarded as honorary fellow of the American College of Radiology in May 2017 and received the Jacob Fabrikant award of ISRS in June 2017. In 2018 he was awarded as FASTRO. He is past-president of the American Radium Society (2017-8), was member of the Board of ISRS (2013-2017) and is on the Board directors of the Radiosurgery Society since 2016. In 2020 he became president of ESTRO.

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