The ability to cure several pelvic malignancies is hampered by the inability to deliver doses greater than 45 to 50 Gy, beyond which radiation enteritis becomes dose-limiting. The design and fabrication of a device that allows exclusion of small bowel from the pelvis during radiation therapy are described in this study. A prospective dose-volume analysis conducted on 30 patients reveals a 66 percent reduction in the volume of small bowel within the radiation portals.