A simple manual method of repositioning small bowel during pelvic irradiation.
Small intestine is often unnecessarily irradiated during radiotherapy because it lies near tumor volumes and thus may be dose limiting. Repositioning of normal tissues can sometimes be accomplished by mechanical rather than invasive surgical techniques. At our institution, physical displacement of small bowel tissues was carried out on a population of patients with good result. Patients suffering from prostatic, cervical, and rectal carcinoma were treated using a custom built and padded block composed of rigid Styrofoam. The block, in most cases, successfully displaced significant amounts of healthy tissues from treatment fields. Maximum displacement of bowel was accomplished at the time of simulation using fluoroscopy and manual positioning of the device. The optimum displacement position and location of the Small Bowel Displacement Device (SBDD) were recorded by means of orthogonal radiographs. The device was affixed to a piece of mylar that had been previously scribed with an X and Y coordinate system, which could be used to permanently anchor the SBDD to its position of maximum displacement. Displacements of as much as 4.0 to 5.0 cm were noted on most patients. Patients generally tolerated the device well as long as they were able to lie prone. Patients with recent abdominal surgery were less likely to tolerate the SBDD, and omental slings or meshes generally precluded movement of the small bowel.