Sensible Introduction of MR-Guided Radiotherapy: A Warm Plea for the RCT

Abstract

Magnetic resonance guided radiotherapy (MRgRT) is the newest face of technology within a field long-characterized by continual technologic advance. MRgRT may offer improvement in the therapeutic index of radiation by offering novel planning types, like online adaptation, and improved image guidance, but there is a paucity of randomized data or ongoing randomized controlled trials (RCTs) to demonstrate clinical gains. Strong clinical evidence is needed to confirm the theoretical advantages of MRgRT and for the rapid dissemination of (and reimbursement for) appropriate use. Although some future evidence for MRgRT may come from large registries and non-randomized studies, RCTs should make up the core of this future data, and should be undertaken with thoughtful preconception, endpoints that incorporate patient-reported outcomes, and warm collaboration across existing MRgRT platforms. The advance and future success of MRgRT hinges on collaborative pursuit of the RCT.

A virtual phantom for patient‐specific QA On A 1.5T MR‐linac

“…The MLC leaves move in the superior/inferior direction with respect to patient anatomy, with a leaf width of 7.2 mm at the isocenter plane. The maximum field size in the isocenter plane is 57.4 × 22.0 cm 2 . In treatment mode, the treatment table can move in and out of the bore, while its position in the vertical and lateral directions is fixed.…”

“…MR-linacs have seen a significant increase in clinical implementation. 1,2 However, integrating an MR-scanner into a linac also presents new challenges for system commissioning and patient-specific quality assurance (QA). [3][4][5][6][7] One of the challenges in MRgRT is the electron return effect (ERE), which occurs due to the Lorentz force that causes deflection of secondary electrons, leading to changes in the delivered dose to the target and an increase in surface dose.…”

“…This integration enables adaptive therapy, which adjusts the treatment plan for each fraction based on the patient's anatomy at the time of treatment, leading to improved accuracy and reduced risk of side effects. MR‐linacs have seen a significant increase in clinical implementation 1,2 . However, integrating an MR‐scanner into a linac also presents new challenges for system commissioning and patient‐specific quality assurance (QA) 3–7 …”

Magnetic resonance imaging (MRI) guided proton therapy: A review of the clinical challenges, potential benefits and pathway to implementation

“…The clinical trial outcomes should be benchmarked against non-MRI-guided proton therapy and MRI-Linac therapy to best estimate the impact of the combined MRI-proton therapy technology. Ideally, clinical trials should be in the form of randomised trials comparing MRI-guided proton therapy with photon therapy and these should be conducted to obtain evidence of clinical benefit and to support appropriate clinical dissemination and financial reimbursement [110]. We should do randomised studies, which provide high level evidence, and these should be conducted early in the clinical implementation of MRI-guided proton therapy, where there is more likely to be clinical equipoise.…”

Radioligand-Guided Radiation Therapy Planning

“…They reported "significant PTV reductions resulting from PET/MR compared to with MR alone, with associated increased max and mean BED [biologically effective dose] planned to the PTVs and reduced max and mean doses to OARs [organs at risk]." 8(px) Similarly, to the plea made by Verkooijen and Henke 9 regarding the introduction of gathering information on the establishment of MR-guided radiation therapy, further clinical studies are required to establish the benefit of this application (vs overheads) in treatment planning.…”