胸段食管癌三维适形放疗摆位误差研究  

Setup error in three-dimensional conformal radiotherapy for thoracic esophageal carcinoma

作　　者：洪金省[1] 张纬建[1] 陈金梅[1] 蔡传书[1] 柯春林[1] 陈秀英[1] 吴彬[1] 郭飞宝[1] 

机构地区：[1]福建医科大学附属第一医院放疗科,福州350005

出　　处：《中华放射肿瘤学杂志》2009年第3期182-185,共4页Chinese Journal of Radiation Oncology

基　　金：福建省自然科学基金资助项目（X0750028）;福建省卫生厅青年基金资助项目（2006-1-9）

摘　　要：目的应用电子射野影像装置（EPID）测量胸段食管癌三维适形放疗（3DCRT）的摆位误差，推算P1V与CTV之间的间隙。方法对41例胸段食管癌患者每周拍摄1次正侧位EPI，通过比较EPI和数字重建影像（DRR）的差异来测量摆位误差。根据公式计算出1yrV与CTV之间的间隙。采用自身配对设计对22例接受根治性放疗患者应用不同PTV与CTV的间隙值分别设计两套模拟治疗计划，A组x、y和z轴均为10mm，B组采用本研究结果的间隙值。应用配对t检验或Wilcoxon符号秩检验来比较两套计划间的差异。结果x、y、z轴的PTV与CTV的间隙值分别为8．72、10．50、5．62mm。两套模拟计划间的脊髓最高照射剂量不同，A计划为（4638．7±1449．6）cGy，B计划为（4310．2±1528．7）cGy（t=5．48，P=0．000）；脊髓并发症概率也不同，A计划为4．82％±5．99％，B计划为3．64％±4．70％（Z=-2．70，P=0．007）。结论笔者单位胸段食管癌接受3DCRT时在x、y和2轴上的PIV与CTV之间的间隙值分别为8．72、10．50、5．62mm；与3个轴均为10mm的间隙值相比应用本研究结果制定治疗计划可更有效地保护脊髓。Objective To study the setup errors in three-dimensional conformal radiotherapy （3 DCRT） for thoracic esophageal carcinoma using electronic portal imaging device （EPID） and calculate the margins from CTV to PTV. Methods Forty-one patients with thoracic esophageal carcinoma who received 3DCRT were continuously enrolled into this study. The anterior and lateral electronic portal images （EPI） were aquired by EPID once a week. The setup errors were obtained through comparing the difference between EPI and digitally reconstructed radiographs（DRR）. Then the setup margins from CTV to PTV were calculated. By using self paired design,22 patients received definitive radiotherapy with different margins. Group A： the margins were 10 mm in all the three axes;Group B： the margins were aquired in this study. The difference were compared by Paired t-test or Wileoxon signed-rank test. Results The margins from CTV to PTV in x ,y and z axes were 8.72 ram, 10.50 mm and 5.62 mm, respectively. Between the group A and group B, the difference of the maximum dose of the spinal cord was significant（4638.7 cGy ± 1449.6 cGy vs. 4310.2 cGy ± 1528.7 cGy ; t = 5.48, P = 0.000）, and the difference of NTCP for the spinal cord was also significant （4.82%±5.99% vs. 3.64%±4.70% ;Z = -2.70,P =0.007）. Conclusions For patients with thoracic esophageal carcinoma who receive 3DCRT in author＇s department, the margins from CTV to PTV in x, y and z axes were 8.72 mm, 10.50 mm and 5.62 mm, respectively. The spinal cord could be better protected by using these setup margins than using 10 mm in each axis.

关 键 词：食管肿瘤/放射疗法 放射疗法 三维适形 摆位误差 电子射野影像装置 

分 类 号：R686[医药卫生—骨科学]