Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
Radiother Oncol. 2012 Jan;102(1):22-9. doi: 10.1016/j.radonc.2011.05.076. Epub 2011 Jun 30.
To investigate bowel exposure using prone, supine, or two different belly boards for rectal cancer intensity modulated RT plans using a full bladder protocol.
For 11 volunteers four MR scans were acquired, on a flat table in prone, supine, and on two different belly boards (IT-V Medizintechnik GmbH® (BB1) and CIVCO® (BB2)), using a full bladder protocol. On each scan a 25×2 Gy IMRT plan was calculated.
BB2 led to an average bowel area volume reduction of 20-30% at any dose level compared to prone. BB1 showed a smaller dose reduction effect, while no differences between prone and supine were found. Differences between BB2 and prone, supine or BB1 were significant up to a level of respectively, 45, 35, and 30 Gy. The reducing effect varied among individuals, except for the 50 Gy region, where no effect was found. An increase in bladder volume of 100 cc led to a significant bowel area V15 reduction of 16% independent of scan type.
In the low and intermediate dose region a belly board still attributes to a significant bowel dose reduction when using IMRT and a full bladder protocol. A larger bladder volume resulted in a significant decreased bowel area dose.
研究使用全膀胱方案的直肠癌调强放疗计划中，俯卧位、仰卧位和两种不同腹部垫板对肠道暴露的影响。
对 11 名志愿者进行了 4 次磁共振扫描，分别在平板上俯卧位、仰卧位和两种不同的腹部垫板（IT-V Medizintechnik GmbH®（BB1）和 CIVCO®（BB2））上进行，采用全膀胱方案。在每次扫描中，都计算了 25×2 Gy 的调强放疗计划。
与俯卧位相比，BB2 在任何剂量水平下平均减少 20-30%的肠道面积体积。BB1 显示出较小的剂量减少效果，而俯卧位和仰卧位之间没有发现差异。BB2 与俯卧位、仰卧位或 BB1 之间的差异在分别达到 45、35 和 30 Gy 时具有统计学意义。除了在 50 Gy 区域没有发现效果外，这种减少效果在个体之间存在差异。膀胱体积增加 100 cc 会导致肠道 V15 面积剂量显著减少 16%，与扫描类型无关。
在低剂量和中剂量区域，当使用调强放疗和全膀胱方案时，腹部垫板仍然会显著降低肠道剂量。更大的膀胱体积会导致肠道区域剂量显著降低。
