 Hi, everyone. I'm Carrie Glide-Hurst. I'm the Director of Radiation Ecology Physics at the University of Wisconsin-Madison. And I'm here today with my co-host, Victoria Yu, from Memorial Sloan Kettering. Hi, Victoria. And we're here to share the greatest hits of MR in RT in medical physics in this sense. It's the Journal of Medical Physics. Victoria. Hi, everyone. Again, I'm Victoria Yu. I'm currently at Memorial Sloan Kettering Cancer Center. It's an honor to be able to introduce the greatest hits in MR in RT. So this virtual issue is a compilation of the significant original scientific papers on the topic of MR in RT that is published here in medical physics. And the way we selected papers is a combination of various topics, but it arranges from historic classics to some landmark publications and MR simulation for radiation therapy, and then also some of the latest publications that feature the newest hot topics. So we hope this virtual issue will give all the readers the opportunity to reflect on the developments in MR in RT, all the things we accomplished in this short period of time, and also gain some insights on the new developments. Great. Thanks so much, Victoria. So I'll kick it off with track one. The first selection is an oldie but a goodie. This is from all the way back in 1996, an article by Dr. Shank. It's a review article, and it's the role of magnetic susceptibility in MRI and MR compatibility of the first and second kind. So this is one of the very first publications in MRI in medical physics has a whopping 905 citations. So we really felt we needed to include it. Still remains a really great reference for any library. Victoria, with the next one. The next one I'm introducing is radiation therapy dosimetry using magnetic resonant imaging of polymer gels might sound very unrelated when we're saying MR in RT. However, interestingly, the first paper that had any any reference of combining MR and radiation therapy is actually on gel dosimetry with MRI. So that's why we included this landmark paper. It's also introduced in 1996. Yeah, hard to believe it. 1996 is when we first had the first MR and RT paper and then it went to a dosimetry gel paper. So it was pretty interesting to dig out over the years. So the next one that came from 2009. So now we're getting into the 2000s. So bring all your boy band trivia. So this one was by Geno Fallone's group, really important work looking at the first MR images during mega voltage photon irradiation from a prototype MR Linux. So this is really one of the first MR Linux papers, which we know led way to a lot of other papers in the future. But really important work and we look forward to seeing more come out from that group. And then I have the next one too, also in 2009. So this one is by Leslie Baldwin and also from Geno Fallone's group. And this is a two step scheme for distortion rectification for MRI. So this one is a really important work. I use this pretty regularly in a lot of my research and clinical work for our gradient non linearity assessments in our magnets. And so it's really one of the first distortion papers and has really sound science and remains a really strong reference. And Victoria with the next one. The next one I'm introducing here four dimensional magnetic resonance imaging using image based respiratory surrogate feasibility study. So when exploring the topics on MRI and RT, one of the main topics was for the MRI. And this one was selected because it's the most highly cited one. So this is from Dr. Jean Kai from Duke University. So this work is the first one that featured the use of an patient volume based surrogate instead of any external or navigation surrogate as a way to incorporate respiratory gating in 40 MRI. So we thought that was a good reference to be included. Yeah, that's really one of many papers that came out of that group in 40 MRI, but one of the first. So the next one that we selected was the characterization of tissue, magnetic susceptibility distortions for our guided RT. This is from Teos Dinescu up at PMH and colleagues. And this is really one of these great simulation papers that talk about the influences of the magnetic susceptibility and the size of the cavity and the different material effects and what we can see in our RT images. So a lot of these principles apply and they are really good fundamental paper. Published in 2012. The next paper kind of switches gears, but we liked having a little bit of diversity in the selections. This comes from Paulus et al. And it's looking at integration of pet MRI hybrid imaging into treatment planning. So this was published in 2014. And we were really excited about seeing this work. This is one of many that are to come. Pet MRI is a very hot topic. We're seeing a lot in synthetic CT correction from MR data and a lot of really interesting work coming up. So we think we'll be seeing a lot more of it. And so we thought it was good to feature this kind of initial work by that group. Along those same lines, some of the really great fundamental work in MR simulation presented out of Medical College of Wisconsin. Eric Paulson and colleagues published in 2015. One of the very first comprehensive reports on MR sim in radiation oncology for external beam radiation treatment planning. So Eric Paulson and I just published our task group 284. And a lot of the work that was shared in this initial paper was highly relevant in our latest task group publication. And just really, really great comprehensive work and looking at coil configurations, patient setups, distortion assessment. So there's a lot of good information there for kind of those that are new to the MR sim world. And stay tuned for the task group coming your way. Victoria, you're up next. Yep. So the next one I'll be introducing is longitudinal diffusion MRI for treatment response assessment preliminary experience using an MR guided tricobalt 60 radio therapy system. So this is from Dr. Ying Li Yang, one of my former colleagues at UCLA. Great team, great group there. So this is published in 2016. It's one of the first publications that looked at low field, being able to do low field diffusion weighted imaging on a MR guided system, V-Ray in particular. So the reason why this is so exciting is because first of all, low field is difficult and they did a great job in being able to robustly track the ADC values for a variety of patients. And also the opportunity of MR guided system gives that new avenue of being able to get multiple time points of diffusion mapping. So that kind of introduced that very exciting avenue that MR guided systems give and treatment responses. Yeah, definitely. That longitudinal imaging is so valuable. One of the things we don't know quite what's actionable or not, but I think there's more to come on that. A lot of really good work coming out of UCLA looking at that DWI. The next paper is a multi-center validation of prostate tumor localization using multi-parametric MRI and prior knowledge. So this work is from NKI, Dr. Renderheat. So this was a very comprehensive analysis on combining multiple features from multiple centers on prostate cancer patients. So this included a DC MRI, dynamic weighted MRI, and also just the T2 weighted and generated lots of features from that. And the main thing that they also added and had a prior knowledge mapping of the probability map of tumor occurrence in the prostate. So that prior knowledge helped increase the distinguishability of the tumor itself. So it achieved a very, very nice results. And the main interesting part of this is actually the ground truth was the entire prostate biopsy slides, which I thought was a really comprehensive evaluation. So that's why we picked this great paper. Yeah, it's so valuable to have those correlates with pathology, but so hard to do. So kudos to the study group for that and also being multi-center, also really hard to do. So hats off to that group and that team for putting that together. So the next paper is from 2017 from Zhao Han. And this is one of the very first synthetic CT papers from MR data using a deep convolutional neural networks. And so this one has, despite being only published three years ago, has over 190 citations. And I know I cited often myself as one of the first real deep learning implementations and really highly accurate synthetic CT generated in seconds. So there's a lot of potential. We've seen a lot of different variations come up over the years in this method. But there is definitely one of the very first papers and well deserving to be on our list. Next is Monte Carlo study of ionization chamber magnetic field correction factors as a function of angle and beam quality. This is by Molkov and Rogers. This is landmark work on characterizing all the dosimetry properties of various chambers for reference dosimetry measurements in consideration of the magnetic field. So it's a very comprehensive and included the simulated scenario for both the Unity, MR Linux, same energy, 7MV, and 1.5 Tesla, and also for view racism of 0.35 T. So this will remain a very, very useful reference for everyone in the MR guided world. So, okay, the next is cardiac substructure segmentation with deep learning for improved cardiac sparing. So this is a great paper by Eric Morris and also Kerry Gladhurst here. It's a really impressive paper that took a pair of MR cardiac imaging and paired it with CT, non-contrast CT for deep learning training and then was able to have very high performance segmentation of very 12 different cardiac substructures with really great accuracy. So this really holds the promise of being able to do these cardiac cardiac structure contouring for future radiotherapy planning. So one of the new and hot topics. So yeah, one other thing, you know, what I like about my own paper, but my student's paper, I should say, Eric Morris, but really it's about what MRI enables you to do and that allows you to have, you know, better segmentation. So we'd be remiss if we didn't include, you know, a segmentation work and also incorporating deep learning, I think. So it helps. It's my own paper that I do love, but we know cardiac substructures are going to be even more important in the future in planning. So we wanted to make sure we touched on the cardiology component. Speaking of hot topics, here's another one. Another hot topic is initial assessment of 3D magnetic resonance fingerprinting towards quantitative brain imaging for radiotherapy. So as we, MR fingerprinting is a new and hot topic, even in the diagnostic world, where a brand new way of acquiring images allowed for a simultaneous generation of quantitative imaging maps. So this is the first evaluation in medical, general medical physics that focused specifically for radiotherapy applications. So this paper included the optimizes the sequence on radiotherapy setup, coil setup, and had a very extensive repeatability variability analysis on various scanners and phantoms as well. So we thought this brand new and hot topic is very exciting. Yeah, and that was from Lou et al, right? Lou et al. Speaking of Lou, our 15th paper selection is also from Dr. Paul Lou and Paul Kiehl's group out in Australia. And so our final selection, the first experimental investigation of simultaneously tracking two moving targets, moving independently in an MR using, MRLINEC using MRI and LLC tracking. So we know that our patients are coming back and they might have multiple tumors working in different directions. And so this is some really premier work under early access just in November of 2020. Also received a best in physics award at the 2020 annual meeting. And so this is going to be really important work when we start thinking about truly real time adaptation, you know, real time on the fly, you know, MLC tracking of moving targets, not just one target, but multiple targets. So stay tuned for more really great work out of the Imagex team and Australia group. It's going to be impressive, I'm sure. So Victoria, do you think I should tell them about our two secret tracks that we had? What? Sure. So, you know, no record or, you know, greatest hits is complete without some secret tracks. And so, you know, we'd be remiss if we didn't mention some of the really early work published back in 2005 and 2006 on the very first MR guided external beam system. So Dempsey et al. presented at 8 p.m. in 2006 on their real time MR guided. And then beat very narrowly with the presentation by Jan Lagendike and boss Raymakers and colleagues back in 2005. And that was using the in room magnetic resonance image guided radiation therapy. So while we don't have full papers to kind of contribute, you know, we really think that this is an important topic. And we really want to encourage our authors to consider to submit their full papers to medical physics and to really allow us to all gain from the knowledge and the research that has been conducted. So with that, I wanted to thank Victoria for joining me in putting this virtual issue together. It's been really fun working with you. And do you have any other things you want to add? It's just pretty amazing how much has happened since 2006. And really, really, we're all just very excited to see the new developments in the future. Yeah, so I look forward Victoria from seeing more of your work in medical physics. And thanks everyone for joining us today and take a look at those papers. Thank you. Thank you. Bye bye.