This trial tests the use of a disposable perfusion phantom (P4) to decrease errors in calculating the blood flow of a tissue with DCE-MRI. DCE-MRI is used calculate blood flow of various tissues including tumors. Blood flow often serves as a critical indicator showing a disease status. For example, a pancreatic tumor has typically low blood flow, so it can be used as an indicator to identify the presence of a pancreatic tumor. In addition, an effective therapy may result in the increase of blood flow in a pancreatic tumor during the early period of treatment. Therefore, DCE-MRI may be used to determine whether the undergoing therapy is effective or not by measuring the change of blood flow in the pancreatic tumor and may help doctors decide whether to continue the therapy or try a different one. Unfortunately, the measurement of blood flow using DCE-MRI is not accurate. The use of an artificial tissue, named "phantom" or P4, together with a patient may help to reduce errors in DCE-MRI because errors will affect the images of both the patient and the phantom. Because it is known how the blood flow of the phantom appears when no errors are present, the phantom may be used to detect what kinds of errors are present in the image, how many errors are present in the image, and how to remove errors from the image.