Technical Radiotherapy Advances - The Role of Magnetic Resonance Imaging-Guided Radiation in the Delivery of Hypofractionation

Safe delivery of hypofractionated radiotherapy requires high levels of accuracy due to the high doses of radiation delivered per fraction. Magnetic resonance guided radiotherapy (MRgRT) represents a new treatment paradigm which allows improved visualisation of targets and organs at risk, alongside the capability to adapt the treatment plan in real time prior to treatment delivery. There are challenges to delivering hypofractionated radiotherapy with conventional image guided radiotherapy (IGRT) techniques and MRgRT may help to improve accuracy in radiation delivery in a number of clinical and anatomical scenarios. Specifically, there is an emerging role of MRgRT in delivering stereotactic body radiotherapy (SBRT) for locally advanced pancreatic cancer (LAPC) due to the superior soft tissue contrast provided by Magnetic Resonance Imaging combined with the ability to accommodate variation in anatomical appearances during treatment delivery. Reported data on the use of MRgRT in LAPC and it's role in enabling dose escalation are discussed in this article. There are further potential benefits to the use of MRgRT, for example the use of functional imaging during treatment delivery and generation of synthetic computed tomography, which have previously been impractical or unachievable. The overall aim of this article is to demonstrate the utility of MRgRT in facilitating safe delivery of hypofractionated radiotherapy and to highlight ways in which it may help to overcome challenges posed by current IGRT techniques. (C) 2022 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

Automated summary

Hypofractionated radiotherapy requires high accuracy, and the use of Magnetic Resonance guided radiotherapy (MRgRT) offers improved visualization and adaptation capabilities for treatment planning. MRgRT has shown potential in delivering stereotactic body radiotherapy (SBRT) for locally advanced pancreatic cancer (LAPC), due to its superior soft tissue contrast and ability to accommodate anatomical variations. The use of MRgRT also opens up possibilities for functional imaging and synthetic computed tomography. The aim of this article is to demonstrate the utility of MRgRT in safe delivery of hypofractionated radiotherapy and address challenges posed by conventional image guided radiotherapy techniques.