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Purpose: We present feasibility studies in support of a real‐time MRI guided external beam radiotherapy delivery system currently under commercial development. Method and Materials: The system, (ViewRay Inc., Renaissance™), combines a low field open MRI scanner and a multi‐headed 60Co γ‐ray IMRT unit equipped with multi‐leaf collimators. It is designed so that the center of the field of view of the MRI and the isocenter of the radiotherapy unit coincide. The inherent compatibility of the units allows for the acquisition of fast ciné MRI simultaneous to radiotherapy delivery to assess intra‐fraction organ motion. Computational feasibility studies were performed to investigate: the compatibility of the MRI and the 60Co γ‐ray IMRT unit; the impact of the MRI magnetic field on the dosimetry; and the feasibility of performing accurate heterogeneity dose computations with MRI data. Results: The 60Co γ‐ray IMRT unit was found not to significantly impact the operation of the MRI; the γ‐ray IMRT unit is capable of producing high quality IMRT treatment plans; the MRI magnetic field eliminates contamination electrons and does not significantly perturb the dose distribution in lung, soft tissue, and bone; and accurate heterogeneity dose computations are possible employing only MRI data. Conclusion: Performing IMRT allows for the seamless integration with, and simultaneous operation of, an open MRI unit. Conflict of Interest: Research sponsored by ViewRay, Inc., Gainesville, Florida USA.

Transforming Urgent and Emergency Care and the Vanguard Initiative For more information on this publication, visit www.rand.org/t/RR2062 Published by the RAND Corporation, Santa Monica, Calif., and Cambridge, UK © Copyright 2017 RAND Corporation R® is a registered trademark. RAND Europe is a not-for-profit organisation whose mission is to help improve policy and decisionmaking through research and analysis. RAND's publications do not necessarily reflect the opinions of its research clients and sponsors. Limited Print and Electronic Distribution Rights This document and trademark(s) contained herein are protected by law. This representation of RAND intellectual property is provided for noncommercial use only. Unauthorized posting of this publication online is prohibited. Permission is given to duplicate this document for personal use only, as long as it is unaltered and complete. Permission is required from RAND to reproduce, or reuse in another form, any of its research documents for commercial use. For information on reprint and linking permissions, please visit www.rand.org/pubs/permissions. Support RAND Make a tax-deductible charitable contribution at www.rand.org/giving/contribute www.rand.org www.rand.org/randeurope iii Preface Urgent and Emergency Care (UEC) vanguards were established in August 2015 as part of the new models of care programme that is considered key to delivering NHS England's Five Year Forward View. They aim to improve the quality, efficiency and effectiveness of UEC services so that patients receive the most appropriate care at the right time and in the right place, and so that unnecessary admissions to accident and emergency (A&E) and hospitals are reduced. The Southern Cluster comprises three such UEC vanguards: those led by Barking and Dagenham, Havering and Redbridge System Resilience Group; Cambridgeshire and Peterborough Clinical Commissioning Group (CCG); and South Devon and Torbay CCG. RAND Europe, together with EY and Julian Elston of the University of Plymouth, were commissioned by the Southern Cluster to evaluate these three vanguards. The evaluation aims to examine the impacts of the vanguards, the processes underpinning delivery (and associated enablers and challenges), and implications for future policy and practice. In doing so, it aims to help inform the continued development of UEC services in these areas and to provide learning of relevance for both local and national level decisionmakers. The primary audiences for this report are commissioners and providers of UEC services, and policy stakeholders such as NHS England. The report may also be of interest to a wider audience of UEC stakeholders, those with a more general interest in the integrated provision of services, researchers, and the wider public. In Section 1 of this report we set out the background and context to UEC service improvement efforts and to the UEC vanguards initiative, and the aims, methods and limitations of this evaluation. We then describe our findings from each of the three Southern Cluster vanguar...

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When dealing with nuclear reactor calculation schemes, the need for 3D transport-based reference solutions is essential for validation and optimization purposes. As SN transport methods may be considered promising with respect to comprehensive parallel computations, a 3D full PWR core benchmark was proposed to challenge the capabilities of the PENTRAN parallel SN code utilizing an IBM-BG/P computer. After a brief description of the benchmark, a parallel performance analysis is carried out, and shows that the parallelizable (Amdahl) fraction of PENTRAN is comprised between 0.994 ≤ f ≤ 0.996 for a number of BG/P nodes ranging from 17 to 1,156. The associated speedup reaches a value greater than 200 with 1,156 nodes. Using a best estimate model, PENTRAN results are then compared to Monte Carlo results rendered using the MCNP5 code. Good consistency is observed between the two methods (SN and Monte Carlo), with discrepancies less than 65 pcm for the k eff , and less than 2.5% for the flux at the pincell level.