Minimization of small bowel volume within treatment fields utilizing customized “belly boards”

Abstract

Thirty consecutive patients with pelvic malignancies were evaluated prospectively for the impact of a novel bowel minimization device (“belly board”) on the volume of small bowel included within a four field pelvic radiation plan. A customized polyurethane and styrofoam bowel immobilization mold was created for each patient in the prone position. Using contrast enhanced CT scanning on a dedicated radiation treatment planning scanner, we imaged the location of the small intestine in the supine position and the prone position aided by the “belly board”. Custom in-house interactive image analysis software was developed to allow volumetric determination of small bowel within the treatment portals. The mean small bowel volume was reduced by 66% (299 cm 3 to 102 cm 3), comparing the standard supine position to the prone position assisted by the “belly board”. In 13 patients without prior pelvic surgery, the small bowel volume reduction was a more dramatic 74% (334 cm 3 to 88 cm 3). All patients were found to benefit from this prone “belly board” setup regardless of body habitus, weight, and age. Compliance with the set-up including use of bladder distension was excellent. All patients completed their pelvic radiotherapy without requiring a treatment break. Weight loss at completion averaged less than 5%. Seventy-six percent of patients experienced little or no diarrhea. This technique is comfortable, inexpensive, highly reproducible, and permits maximal bowel displacement from standard pelvic radiotherapy fields.