Pilot Study of Same-session MR-only Simulation and Treatment With Stereotactic MRI-guided Adaptive Radiotherapy (SMART) for Oligometastases of the Spine

In light of the increasing experience with magnetic resonance image-guided radiotherapy (MRgRT) and adaptive planning and advances in magnetic resonance (MR)-only planning, the investigators propose here to evaluate the feasibility and safety of same-session MR-only simulation and treatment with SMART for spinal metastases. Although spine SBRT is a standard-of-care treatment modality, this expedited same-session MR-only simulation and treatment with SMART workflow is novel. Previously, delivery of spine SBRT has typically required several days from time of consultation to simulation and then 1-2 weeks from simulation to the initiation of treatment. On this proposed study, patients will not undergo computed tomography (CT) simulation and will instead have same-session MR-only simulation and treatment planning, on-table, using SMART. In this manner, patients would initiate treatment within just several days from the consult. Feasibility of the workflow will be defined as successful delivery of the first fraction of same-session MRI-only simulation and treatment with SMART on the first on-table attempt for at least 70% of patients. Patients will be treated in five fractions over 1-2 weeks. Although the long-term goal will be to achieve a significantly shortened time from consult to treatment as compared to traditional stereotactic body radiation therapy (SBRT) using simulation, the present study will be driven by short-term goals of workflow feasibility and safety.