盆腔肿瘤放疗中体位对小肠受照体积的影响

Influence of small intestine exposure with different radiotherapy positioning on pelvic cancer

目的观察不同治疗体位对盆腔照射野内小肠受照体积的影响。方法选择A、B两例盆腔肿瘤患者的腹、盆腔连续性增强CT扫描图像(A患者俯卧于塑形成腹板模型的负压真空气垫,B患者仰卧于负压真空气垫对背、腰、臀部等体表轮廓塑形)。利用放射治疗计划系统(treatment planningsystem,TPS)对两例盆腔肿瘤患者增强CT扫描图像模拟设计出相同条件的放射野及放疗计划,通过剂量-体积直方图(dose volume histogram,DVH)评价模拟设计的放疗计划中盆腔照射野内A、B两例患者小肠接受放射线照射体积占各自全部肠管体积的百分比并进行比较。结果在TPS下模拟设计的放疗计划中,A患者小肠受照体积占自身总肠管体积的33.67%,B患者小肠受照体积占自身总肠管体积的46.16%。结论盆腔肿瘤放疗中患者采取俯卧于负压真空气垫腹板模型的治疗体位可明显减少小肠接受放射线照射的体积,进而有可能减轻肠道急性放射反应及晚期放射性损伤,提高患者放疗耐受性及生存质量(quality of life,QOL)。

Objective To evaluate the changes of radiation volume ratio(exposure volume/total volume) of small intestine exposure with different radiotherapy positioning. Methods The two patients(A and B) with pelvic cancers received abdominal-pelvic enhancement CT scan after patient A prone on negative pressure vacuum cushion abdominal plate model and patient B back to the negative pressure vacuum cushion.Design radiation treatment plan by treatment planning system(TPS) for two patients(A and B) with pelvic cancer.The radiation volume ratio of small intestine exposure to irradiation was detected by dose-volume histogram(DVH figure) in radiotherapy simulation plan designed with the same radiation fields. Results The radiation volume ratio of small intestine of patient A was 33.67 % and patient B was 46.16 %. Conclusions The radiation volume of small intestine of patients with pelvic cancer is decreased by using radiotherapy positioning that prone on the negative pressure vacuum cushion abdominal plate model.Improving the patient's(with pelvic cancer) quality of life after radiotherapy and reducing the acute/ chronic intestinal radiation response can be possible.