RESUMEN
BACKGROUND: The aim of this study was to investigate the effect of a belly board (BB) with the addition of a bladder compression device (BCD) for small bowel (SB) displacement from the radiotherapy field for rectal cancer. PATIENTS AND METHODS: Computed tomography (CT) scans of 38 rectal cancer patients positioned on a BB were analyzed and compared with CT scans from the same patients after the addition of a BCD. The BCD moves the inferior border of the BB from the pubic symphysis to the lumbosacral junction. The treated and irradiated volumes of the SB and bladder were compared. The irradiated volume ratio of SB to abdominopelvic cavity (APC) and that of bladder to APC were analyzed. RESULTS: With the BCD, the treated and irradiated volumes of SB decreased significantly (49.1 ± 48.0 vs. 60.9 ± 50.9 cc, p = 0.006 and 207.5 ± 140.8 vs. 482.8 ± 214.2 cc, p < 0.001, respectively). The irradiated volume ratio of bladder to APC with the BCD increased considerably compared to that without the BCD (25.2 ± 11.5 vs. 18.7 ± 10.5%, p < 0.001), and the ratio of irradiated volume of SB to APC decreased significantly with the BCD (18.8 ± 12.4 vs. 31.8 ± 12.1%, p < 0.001). CONCLUSION: This study showed that the addition of a BCD to the BB could effectively provide further displacement of SB from the rectal cancer radiotherapy field.