Internal Radiation Therapy With Y-90 Microspheres, External Radiation Therapy With Tomotherapy, and Fluorouracil in Treating Patients With Newly Diagnosed or Recurrent Pancreatic Cancer and Liver Metastases That Cannot Be Removed By Surgery

RATIONALE: Specialized radiation therapy that delivers a high dose of radiation directly to the tumor may kill more tumor cells and cause less damage to normal tissue. Drugs used in chemotherapy, such as fluorouracil, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Giving radiation therapy in different ways and giving it together with chemotherapy may kill more tumor cells. PURPOSE: This phase II trial is studying the side effects and how well giving internal radiation therapy and external radiation therapy together with fluorouracil works in treating patients with newly diagnosed or recurrent pancreatic cancer and liver metastases that cannot be removed by surgery.