Radiation Oncology Speakers

Dr Ratchapas Romrattaphan

Dr Ratchapas Romrattaphan, MD, is a Radiation Oncologist at the Division of Radiation Oncology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.

My clinical practice encompasses genitourinary, gynaecological, gastrointestinal, hepatobiliary, and haematological malignancies, with clinical experience in online adaptive radiotherapy with MR-Linac and brachytherapy. I have research experience in MR-guided adaptive radiotherapy, including as an investigator in the DOTA-2 trial, a Phase II randomised study evaluating two- versus five-fraction MR-guided adaptive stereotactic body radiotherapy with dominant intraprostatic lesion-targeted boost in localised prostate cancer, published in Clinical Oncology in 2026.

Dr Giles Maskell

Dr Giles Maskell is a consultant radiologist based at the Royal Cornwall Hospital in Truro, UK, since 1991. From 2013 to 2016 he was President of the Royal College of Radiologists. He has lectured widely and written extensively on aspects of radiological practice. He has a particular interest in radiological error – the perceptual, cognitive and cultural reasons behind it and strategies for preventing or reducing it – and in the development and maintenance of a healthy culture in radiology departments, together with the impact that can have on reducing stress and burnout. He is clinical lead for the Getting It Right First Time (GIRFT) radiology workstream, an improvement programme in the English NHS.

Prof Matthias Guckenberger

Matthias Guckenberger, MD, is Chairman of the Department for Radiation Oncology, University Hospital Zurich (USZ), and Professor at the University of Zurich (UZH). Integration of advanced imaging and radiotherapy into multimodality treatment of lung cancer has been a major research focus, especially stereotactic body radiotherapy (SBRT) for early stage NSCLC and oligo-metastatic disease. Safety and efficacy was evaluated in prospective clinical trials, in large multi-institutional and national patterns of care analyses. Mathematical and imaging-based modeling of tumor and normal tissue response to radiotherapy has been another focus. He currently serves as president of the ESTRO society.

Dr Shaun Ho

MBBS, FRCR (Clinical Oncology), FAMS, MRCS, GDPM

Dr. Shaun Ho is a Radiation Oncologist and the Medical Director of Proton Therapy SG, one of Southeast Asia’s pioneering proton therapy centres.

A graduate of the National University of Singapore, Dr. Ho completed his specialist training in radiation oncology at the National Cancer Centre Singapore (NCCS) and received his Fellowship from the Royal College of Radiologists (UK). He expanded his expertise through a clinical oncology fellowship at University College London Hospital and advanced his specialisation in proton beam therapy (PBT) at the Kobe Proton Therapy Center in Japan and Taipei Medical University in Taiwan.

Dr. Ho specialises in the management of gastrointestinal cancers, head and neck oncology, and sarcomas. In addition to his practice at Proton Therapy SG, he serves as a Visiting Senior Consultant at Icon Cancer Centre Singapore and Raffles Hospital, where he previously established the radiotherapy department.

Prof Supriya Chopra

Supriya Chopra is a Professor in Radiation Oncology at ACTREC, Tata Memorial Centre, India. She is known for her work in gynecological cancer. Her work within the phase III trial PARCER lead to IG-IMRT becoming the standard of care for cervix cancer. She is Principal Investigator for Phase III RCT that tested protease inhibitor (Nelfinavir Mesylate) in cervical cancer (NELCER). She has successfully lead global research projects with different research groups BIOEMBRACE (translational research in cervix cancer), RETROCOSMOS (recurrent/metastatic cervical cancer). She has been involved with IAEA to map access to Image guided brachytherapy for cervical cancer.She has been instrumental also in developing MOSES score for late adverse event burden in gynecological cancers. On the research side she is focussing on developing framework for TCP, NTCP modelling for postoperative RT and Reirradiation.

She was Associate Editor for IJROBP Gyn section. She is presently Associate Editor for Journal of Clinical Oncology-Global Oncology and Section Editor for Gyn for the Green Journal. She serves as Chair of research commitee for Federation of Asian Radiation Oncologists and has been instrumental in setting the FARO Research Network (FERN) for multicentric studies in Asia. She is the Chair Elect (2028-2031) for GEC ESTRO Gyn Working group and member of ESTROP Gyn Focus group. She currently leads the reirradiation initiatives within GEC ESTRO and ESTRO Gyn Focus Group.

Prof Ananya Choudhury

Prof Ananya Choudhury is a clinical academic specialising in medical oncology and radiation oncology, with a research focus on prostate and bladder cancer biology and treatment optimisation. Her work centres on improving outcomes through translational research, including radiotherapy innovation, tumour microenvironment studies, and biomarker development to guide personalised treatment. She is actively involved in clinical trials and collaborative international research aimed at advancing urological cancer care. Alongside her research, she is committed to mentoring trainees from around the world and fostering multidisciplinary collaboration in genitourinary oncology.

Prof Simon Lo

MB, ChB, FACR, FASTRO
University of Washington Medical Center/ Fred Hutchinson Cancer Center
United States

Dr Simon Lo is Professor of Radiation Oncology and Neurological Surgery at the University of Washington (UW). He is also Director of SBRT at UW. He completed his FRCR (UK) training in Clinical Oncology before he did his radiation oncology training in the US. He has been treating patients with stereotactic body radiotherapy (SBRT) for various body sites since 2004 when he was at Indiana University. Dr Lo has edited 5 comprehensive textbooks in SRS/ SBRT in addition to 4 other comprehensive textbooks and has published >300 full peer-reviewed papers with a majority of which on SRS/ SBRT for all body sites, including publications in Lancet Oncology, JAMA Oncology, Science Translational Medicine, Journal of Clinical Oncology, and Neuro Oncology. He has built or led the SBRT programs in 3 NCI-designated Comprehensive Cancer Centers. He is a member of the Board of Directors and the Medical Director of the Distinction in Practice of Stereotactic Radiotherapy Accreditation Program for Radiosurgery Society. He is also Steering Committee Member for International Stereotactic Radiosurgery Society Guidelines for Extracranial Sites. Dr. Lo has led or participated in numerous guidelines in CNS tumors, spinal metastasis, bone metastasis, renal cell carcinoma, SRS, and SBRT. He is a Fellow of ACR and ASTRO. In 2019, he was granted the Lifetime Achievement Award by the Society for Palliative Radiation Oncology. He is the Past President of the Radiation Oncology Chapter of American College of Radiology. He is also a cofounder of the International Radiosurgery Consortium of the Kidney (IROCK). He is the Scientific Program Chair of American Radium Society. Dr. Lo has won national teaching awards (ARRO) and is a member of the American Board of Radiology Oral Examination Committee in Central Nervous System and Pediatric Tumors.

Dr Deepak Khuntia

M.D., FASTRO
Sr. Vice President, Chief Medical Officer

Deepak “Dee” Khuntia, M.D., joined Varian in 2013 and leads the office of Medical Affairs, which is responsible for providing medical-clinical expertise to all Varian operations, including clinical research, medical evidence generation, medical science education, product development, product support, regulatory affairs, government affairs, mergers and acquisitions.  Dr. Khuntia has played a leading role in innovating and bringing new cancer treatment and cardiac radiosurgery technologies to hospitals worldwide. 

In addition to his responsibilities at Varian, Dr. Khuntia continues to hold a part-time clinical practice in Radiation Oncology in the San Francisco Bay Area, where he has a special interest in advanced radiation treatment technologies, central nervous system tumors, head and neck cancer, and lung cancer. 

Dr. Khuntia is a board-certified radiation oncologist and Fellow of the American Society for Radiation Oncology.

Dr. Khuntia holds both undergraduate and medical school degrees from the University of Illinois, and completed his residency in Radiation Oncology at the Cleveland Clinic.  Prior to moving to the Bay Area, he was an Associate Professor at the University of Wisconsin, where he served multiple leadership roles including Residency Director, Director of Radiation Oncology Outreach, and Course Director of Oncology for the Medical School. Dr. Khuntia is considered an expert in brain tumors, head and neck cancer, and lung cancer and has published more than 100 articles, book chapters, and abstracts.

Prof Giuseppe Minniti

Giuseppe Minniti, MD, PhD, is Professor of Radiation Oncology at Sapienza University of Rome and leads the brain and spine radiotherapy and stereotactic radiosurgery programme at Ospedale Isola Tiberina – Gemelli Isola in Rome. His clinical and research activities focus primarily on neuro-oncology, with particular expertise in radiotherapy and stereotactic radiosurgery for primary and metastatic brain tumours, as well as in the integration of radiation therapy with systemic treatments. Professor Minniti is a member of the Executive Board and Chair of the Scientific Committee of EANO, Treasurer of the EORTC Brain Tumour Group, and Chair of the ESTRO CNS Guidelines Committee. He has authored more than 350 peer-reviewed scientific publications.