Professional paper
https://doi.org/10.20471/acc.2022.61.s3.9
MRI-Guided Radiotherapy for Prostate Cancer: a New Paradigm
Jure Murgić
orcid.org/0000-0001-8152-0494
; Department of Oncology and Nuclear Medicine, Sestre milosrdnice University Hospital Center, Zagreb, Croatia
Marin Gregov
; Department of Medical Physics, Sestre milosrdnice University Hospital Center, Zagreb, Croatia
Iva Mrčela
; Department of Medical Physics, Sestre milosrdnice University Hospital Center, Zagreb, Croatia
Mirjana Budanec
; Department of Medical Physics, Sestre milosrdnice University Hospital Center, Zagreb, Croatia
Marco Krengli
; Department of Translational Medicine, University of Eastern Piedmont, Novara, Italy; Department of Radiation Oncology, ‘Maggiore della Carità’ University Hospital, Novara, Italy
Ana Fröbe
; Department of Oncology and Nuclear Medicine, Sestre milosrdnice University Hospital Center, Zagreb, Croatia; School of Dental Medicine, University of Zagreb, Zagreb, Croatia
Pierfrancesco Franco
orcid.org/0000-0003-2276-0687
; Department of Translational Medicine, University of Eastern Piedmont, Novara, Italy; Department of Radiation Oncology, ‘Maggiore della Carità’ University Hospital, Novara, Italy
Abstract
Radiotherapy is one of the key treatment modalities for primary prostate cancer.
During the last decade, significant advances were made in radiotherapy technology leading to increasing
both physical and biological precision. Being a loco-regional treatment approach, radiotherapy
requires accurate target dose deposition while sparing surrounding healthy tissue. Conventional radiotherapy
is based on computerized tomography (CT) images both for radiotherapy planning and
image-guidance, however, shortcomings of CT as soft tissue imaging tool are well known. Nowadays,
our ability to further escalate radiotherapy dose using hypofractionation is limited by uncertainties in
CT-based image guidance and verification. Magnetic resonance imaging (MRI) is a well established
imaging method for pelvic organs. In prostate cancer specifically, MRI accurately depicts prostate
zonal anatomy, rectum, bladder, and pelvic floor structures with previously unseen precision owing to
its sharp soft tissue contrast. The advantages of including MRI in the clinical workflow of prostate
cancer radiotherapy are multifold. MRI allows for true adaptive radiotherapy to unfold based on daily
MRI images taken before, during and after each radiotherapy fraction. It enables accurate dose escalation
to the prostate and intraprostatic tumor lesions. Technically, MRI high-strength magnetic field
and linear accelerator high energy electromagnetic beams are hardly compatible, and important efforts
were made to overcome these technical challenges and integrate MRI and linear accelerator into one
single treatment device, called MRI-linac. Different systems are produced by two leading vendors in
the field and currently, there are around 100 MRI-linacs worldwide in clinical operations. In this narrative
review paper, we discuss historical perspective of image guidance in radiotherapy, basic elements
of MRI, current clinical developments in MRI-guided prostate cancer radiotherapy, and challenges
associated with the use of MRI-linac in clinical practice.
Keywords
Prostate Cancer; MR-linac; Image-guided Radiotherapy; Online Adaptive Radiotherapy; MR-guided Radiotherapy
Hrčak ID:
286369
URI
Publication date:
1.10.2022.
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