The overall aim of this study is to investigate a novel "dual instance" planning method to make use of the respiratory motion to improve pancreatic radiation therapy (RT) treatment planning.

Specific Aim 1: Acquire patient abdominal MRI and CT at both deep inspiration (INSP) and expiration (EXP) positions and characterize the changes in geometric relationships between the INSP and EXP instances for tumor and normal tissues including stomach, duodenum and bowel. We hypothesize that INSP and EXP MRI and CT characterization will allow identification of patients who may benefit from the dual instance planning method.

Specific Aim 2: Develop, investigate and evaluate plans based on free breathing, single instance breath hold, and the novel dual instance anatomical information. We hypothesize that use of the dual instance method will lead to improved plans, demonstrated by the ability to increase dose to the target, while maintaining the clinically-accepted normal tissue dose constraints.

Inclusion Criteria:

• Any patient with a biopsy proven diagnosis of malignancy involving the pancreas to be treated with radiation therapy
• Age >18 years
• Ability to understand and the willingness to sign a written informed consent document
• Creatinine or creatinine clearance of <1.5 times the upper limit of normal or >45 mL/min/1.73m2 for patients with creatinine levels above normal. Modification of Diet in Renal Disease (MDRD) formula was used to calculate the creatinine level

Exclusion Criteria:

• Patients who are currently receiving any investigational agents
• Unable to undergo MRIs
• Patients with late stage kidney disease or who have had a liver transplant
• Individuals who are allergic to animal dander or have asthma that may be enflamed by proximity to animals will be excluded as the scans will take place in a facility where animal research is also performed.