Additional Study Information: The purpose of this study is to find out if giving intravenous (IV) contrast (a liquid that helps with the visibility of organs and blood vessels that is given through the vein with the use of a hollow needle) during a Cone Beam Computed Tomography (CBCT- a type of computerized X-ray) can help people who have image-guided radiation therapy (IGRT) for the treatment of abdominal and pelvic tumors. Cancers may include uterine cancer, pancreatic cancer, stomach cancer, colon and rectal cancer, liver cancer, and prostate cancer.