Currently, appropriate patients undergo MRI imaging with immobilization and sequences optimized for diagnostic radiology purposes. Using a mutual information algorithm, these images are then registered to a treatment planning CT obtained with custom immobilization to minimize intra-and inter-treatment motion and positional variation. This image registration process is time-consuming and introduces additional layers of geometric uncertainty into what should be a highly precise treatment planning process. However, it is necessary, since radiation dose calculations cannot be performed on MRI data due to the lack of crucial density information. The investigator envisions CT-less treatment planning, using only MRI, due to superior imaging characteristics, fully integrated into the radiation oncology clinic. This study will begin this process.

Inclusion Criteria:

• Patients ≥18 years of age
• A working diagnosis of malignancy in the liver, brain, H&N, or pelvis
• A plan to treat with radiotherapy

Exclusion Criteria:

• Patients with contraindications to having a contrast enhanced MRI scan. These contraindications will be assessed at the time of enrollment using the guidelines set up and in clinical use by the Radiology Department.

Participants having a working diagnosis of malignancy in the liver, brain, head and neck, or pelvis, and a plan to treat with radiotherapy.