Adaptive MRI-Guided SBRT for Unresectable Primary or Oligometastatic Central Thorax and Abdominal Malignancies

The purpose of this research study is evaluate whether it's feasible to give radiation therapy using an MRI-guided adaptive technique. MRI-guided adaptive radiation therapy involves the adjustment or re-planning of treatment day by day while the participant is receiving treatment. The adaptive technique has previously been used in a different fashion to adjust the treatment plan after the fact, but using MRI scanning to re-plan treatment while the participant is still on the table is a new way of using the adaptive technique. This may allow doctors to use more radiation to treat the tumor while better protecting normal tissues. A special radiation treatment machine incorporates both an MRI scanner and radiation treatment devices so that the planning and treatment can be done using the same machine.