Future mainstream platform for online adaptive radiotherapy will be using on-board MR rather than on-board (CB) CT images.

Abstract

As several major non‐inferiority phase 3 clinical trial studies published their promising results, 1 , 2 and as the reimbursement pattern is reforming from fee‐for‐service payment to episode‐based payment, 3 the radiation oncology field is undergoing a major paradigm shift, from a majority of standard fractionation treatments to more hypo‐fractionation and stereotactic body radiotherapy (SBRT). With this change, the need to verify daily radiotherapy dose and adapt the radiotherapy plan according to daily anatomy has become essential. 4 Currently, the most common platforms for online adaptive radiotherapy (ART) include MRI‐guided ART (MRgART) and CT (or cone‐beam CT)‐guided ART (CTgART), both of which have only been adopted by a handful of large‐scale hospital‐based cancer centers around the world. As more experience is collected and technology matures, one would hope that advanced online ART platforms should become more affordable and accessible to a larger community. That brings this month's debate topic: “Future mainstream platform for online adaptive radiotherapy will be using on‐board MR rather than on‐board (CB) CT images.” Herein, we invited Dr. Daniel Hyer and Dr. Bin Cai to join us for this debate. Parallel to this opinion is Dr. Daniel Hyer. Dr. Hyer received his PhD in Medical Physics from the University of Florida in 2010 and was certified by the American Board of Radiology in 2013. Dr. Hyer is currently an Associate Professor and the Director of Clinical Physics at the University of Iowa. His research interests include MRI‐guided radiotherapy and proton beam therapy. On the latter topic, Dr. Hyer currently holds a National Cancer Institute grant for the development of a proton collimator. Clinically, he is the technical director of the Elekta Unity program at the University of Iowa and has been involved with the project since 2017. Opposed to this opinion is Dr. Bin Cai. Dr. Cai is Associate Professor and Director of Advanced Physics Service in the Department of Radiation Oncology at the University of Texas Southwestern Medical Center. Dr. Cai received his Ph.D. in Physics from Ohio University and completed his medical physics residency training at Washington University School of Medicine. Dr. Cai stayed as a faculty member for  6 years at Washington University after residency. In 2021, he joined UT Southwestern to help develop the adaptive radiotherapy program as well as to lead the implementation of biology‐guided radiotherapy. Dr. Cai is one of the key team members that led the clinical implementation of the world's first MRgART platform. Later he also led the clinical development and implementation of the first CBCT‐guided online adaptations in the United States. Therefore Dr. Cai has extensive and balanced experience on both CTgART and MRgART platforms.