MR-guidance in clinical reality: current treatment challenges and future perspectives

Abstract

Magnetic Resonance-guided radiotherapy (MRgRT) marks the beginning of a new era. MR is a versatile and suitable imaging modality for radiotherapy, as it enables direct visualization of the tumor and the surrounding organs at risk. Moreover, MRgRT provides real-time imaging to characterize and eventually track anatomical motion. Nevertheless, the successful translation of new technologies into clinical practice remains challenging. To date, the initial availability of next-generation hybrid MR-linac (MRL) systems is still limited and therefore, the focus of the present preview was on the initial applicability in current clinical practice and on future perspectives of this new technology for different treatment sites. MRgRT can be considered a groundbreaking new technology that is capable of creating new perspectives towards an individualized, patient-oriented planning and treatment approach, especially due to the ability to use daily online adaptation strategies. Furthermore, MRL systems overcome the limitations of conventional image-guided radiotherapy, especially in soft tissue, where target and organs at risk need accurate definition. Nevertheless, some concerns remain regarding the additional time needed to re-optimize dose distributions online, the reliability of the gating and tracking procedures and the interpretation of functional MR imaging markers and their potential changes during the course of treatment. Due to its continuous technological improvement and rapid clinical large-scale application in several anatomical settings, further studies may confirm the potential disruptive role of MRgRT in the evolving oncological environment.

First 500 Fractions Delivered with a Magnetic Resonance-guided Radiotherapy System: Initial Experience

“…With better soft-tissue visualization, accurate IGRT with cMRI and enabling ART to adapt daily anatomical changes of OAR like bowels and stomach, MR-linac can be widely used in areas where conventional systems cannot [10]. With conventional systems, abdominal region is the most feared region to perform radiosurgery.…”

First prospective clinical evaluation of feasibility and patient acceptance of magnetic resonance-guided radiotherapy in Germany

“…Recently, devices integrating an MRI scanner with a treatment delivery system have become clinically available [11][12][13][14][15]. These new hybrid systems for MRgRT do not only offer three-dimensional MRI for soft tissue target and organ at risk visualization, but also allow for continuous cine-MRI before as well as during treatment [12,13].…”

Pooled Analysis of external-beam RADiotherapy parameters in phase II and phase III trials in radiochemotherapy in Anal Cancer (PARADAC)

“…In the aforementioned study, although the addition of cetuximab to Cisplatin/5-FU decreased local failure rates, it came at the cost of increased toxicity [30]. Another study testing this association had to close prematurely due to As MR-Linacs become more widely available, newer techniques such as MRI-guided RT (MRgRT) are being evaluated [50]. Online adaptive treatment strategies may be developed using this technology, considering the clear superiority of MRI imaging for soft tissues.…”