热塑膜体位固定技术在胸部肿瘤体位固定中的应用

目的：探讨胸部肿瘤放疗中热塑膜体位固定和无热塑膜固定情况下对肿瘤内靶区（ITV）大小的影响。方法：选择胸部肿瘤患者10例，每名患者均采用真空负压袋对轮廓定形，分别用热塑膜固定和无热塑膜固定2种方法进行4D—CT扫描，分别采集固定和无固定状态下的4D—CT图像，经TPS图像处理，医生勾画肿瘤ITV，测量固定和无固定时肿瘤ITV体积，计算平均增大体积和统计学数据。结果：热塑膜固定时ITV平均体积为（173．58±223．45）cm2．无热塑膜固定时ITV平均体积为（202．86±230．37）cm2，无固定组平均增大体积为0．39cm2。统计学处理2组数据，差异有显著性（P=0．005）。结论：固定组的ITV体积明显小于无固定组，胸部肿瘤患者放射治疗运用热塑膜体位固定技术值得临床推荐选用。

Application of Thermoplastics in Position Fixation of Thoracic Neoplasm Radiotherapy

Objective To explore the influence of the thermoplastics on internal target volume （ITV） in thoracic neoplasm radiotherapy. Methods Ten patients with thoracic neoplasm were chosen to undergo shape moulding with vacuum bags, and then 4D-CT scanning with and without the thermoplastics fixation. The 4D-CT images with and without the thermoplastics were acquired and processed with TPS, Neoplasm ITVs were contoured by some doctor, and measured to make clear the mean volume increments and statistics data. Results The mean ITVs with and without thermoplastics were （173.58±223.45） and （202.86±230.37）cm2 respectively, and the mean volume increment was 0.39 cm2. There was statisti- cal difference between the data with and without thermoplastics, with P=0.005. Conclusion ITVs with thermoplastics are significantly less than those without thermoplastics, and thus thermoplastics fixation is worth popularizing clinically for thoracic neoplasm radiotherapy.