MRI-Linac treatment for radiotherapy patients. A study on the use of the Australian MRI-Linac to treat cancer radiotherapy patients

Integrated Magnetic Resonance Imaging Linear Accelerators (MRI-Linacs) are one of the newest and most technologically advanced forms of cancer radiotherapy. This study tests the feasibility of the bespoke Australian MRI-Linac to treat cancer patients. It is an imaging and treatment intervention study. The machine is located at Liverpool Hospital and eligible patients will be recruited from Liverpool and Macarthur Cancer Therapy Centres. Consenting patients will first have a radiotherapy CT and MRI simulation per standard of care, followed by a simulation on the MRI-Linac performed by trained MRI radiographer and radiation therapist. From this, a MRI-Linac treatment plan will be generated alongside a standard of care (SOC) treatment plan. These are planned by qualified radiation therapists and physicists, and approved by a radiation oncologist. Treatment contours, doses to organs at risk, and dose prescription will be consistent with standard departmental procedures. Prior to starting treatment, participants will have a non-treatment session on the MRI-Linac, to perform patient-specific imaging, set-up quality assurance (QA) and to assess their tolerance of the procedure and the feasibility of the set-up. If deemed feasible, treatment will proceed on the MRI-Linac. One attempt will be made to remedy any unsuccessful treatment fraction – if this cannot be remedied then the patient will be treated with the SOC plan. During each MRI Linac session, participants will be asked to lie down on the MRI Linac table and positioned inside the MRI Linac. Once inside, a series of MRI scans will be taken. Participants may require some support devices designed to maintain position during the scan and participants may be asked to be in different positions during the scan. All participants will need to attend a minimum of two 1-hour sessions where the MRI-Linac machine will be used to guide radiotherapy treatments. Each session may be from 1 to 7 days apart. If treatment is feasible and each fraction is successfully treated on the MRI-Linac, participants will continue to have their treatment on the MRI-Linac until all of their prescribed treatment fractions are completed. The maximum treatment sessions participants will have on the MRI-Linac is therefore the amount of prescribed fractions per standard of care.