Magnetic Resonance Imaging Simulators for Simulation and Treatment for Patients Requiring Radiation Therapy: A Review of the Clinical Effectiveness, Cost-Effectiveness, and Guidelines

Radiation therapy is a common type of local therapy used to treat cancer, and can be used alone or in combination with chemotherapy, surgery, or both., Approximately 470,000 patients receive radiation therapy each year in the United States of America. In Canada, great progress has been made in cancer control which can be attributed to improvements in prevention, screening, early detection, and treatment options for patients with cancer. This progress has translated into decreased rates of cancer death within Canada over the last three decades (17% in females, 32% in males). In part, this has enabled the field of radiation oncology to investigate other important health outcomes in addition to mortality, such as patient’s quality of life and adverse effects associated with radiation therapy.Accurate treatment planning (e.g., tumor volume, organs at risk) before patients undergo radiation therapy is one way to reduce unnecessary treatment. Computed tomography (CT) simulation is the current gold standard for radiation therapy treatment planning., Radiation treatment planning using CT typically involves obtaining a set of CT images while the patient is immobilized in an adequate position for radiation therapy. These CT images can be used to define the extent of the tumor (i.e., target delineation) and plan treatment delivery (e.g., dose calculation). More recently, magnetic resonance imaging (MRI) has also been used for radiation therapy planning due to its superior soft tissue contrast compared with CT; improved soft tissue contrast may provide more precisely targeted treatment sparing healthy organs at risk of developing comorbidities from radiation. To truly discern whether MRI simulation improves health outcomes and, thus, should be considered for treatment planning for patients who require radiation therapy, a synthesis of the currently available literature is required.The current report aims to summarize evidence regarding the clinical and cost-effectiveness, as well as guidelines for the use of MRI simulators for simulation and treatment planning for patients requiring radiation therapy.