直肠癌术后放疗应用有孔泡沫板对小肠照射剂量的影响

Influence of Bellyboard on Volume and Dose of Small Bowel in Radiatherapy of Post-operative Rectal Cancer

目的探讨直肠癌术后放疗应用有孔泡沫板对小肠剂量的影响。方法8例直肠癌术后患者,俯卧位垫和不垫有孔泡沫板两种体位下,分别进行CT模拟定位。进行3野三维适形计划的设计,比较两种体位下小肠的最高剂量,以及在20、30、40、45Gy等剂量水平小肠受照体积(V20、V30、V40、V45)。结果使用有孔泡沫板时,小肠在20、30、40Gy剂量水平受照体积显著降低(P<0.05);但其受照最高剂量及45Gy剂量水平受照体积减少不明显(P>0.05)。结论直肠癌术后放疗,应用有孔泡沫板能减少小肠的受照体积。

Objective To assess the effect of bellyboard on volume and dose of small bowel in post-operative rectal cancer patients treated with three-dimensional conformal radiotherapy. Methods Eight patients with rectal cancer after radical operation were examined by CT scan.. Two sets of images were taken for the whole pelvis with or without bellyboard. By a 3D planning system＇ a three-field technique was planned. The max dose and dose-volume of small bowel at the 20 Gy,30 Gy,40 Gy,45 Gy dose level （V20,V30,V40,V45） were analysed in the plan of two positions. Results Of the two sets of plans, the volume of the plan with bellyhoard was smaller than without bellyboard at the level V20, V30, V40 for small bowel. However, the max dose and V45 of the plan with bellyboard was not signifieantly lower than without bellyboard. Conclusion Using bellyboard could signicantly reduce the irradiated volume of small bowel for post-operative rectal cancer patient when treated with three-dimensional conformal radiotherapy.