Abstract:

Objective　To analyze the feasibility of personalized polyurethane foam with head, neck, and shoulder masks in craniospinal irradiation. Methods　Eighteen patients taking craniospinal irradiation (CSI) with helical tomotherapy (HT) at Sun Yat-sen University Cancer Center from October 2020 to May 2021 were retrospectively reviewed, including 13 males and 5 females; they were 5-22 years old. Megavoltage CT (MVCT) scanning was performed on all the patients' brains (original lesions), chests (from the first thoracic vertebra to juga), and abdomens (from the third lumbar vertebra to coccyx) before radiotherapy; the MVCT images were matched with the planned ones; the setup errors in the three-dimensional direction were recorded and statistically analyzed by the IBM SPSS 20.0 statistical software. Results　The setup errors in the three-dimensional direction of brain were (-0.18±1.47) mm, (-0.56±1.49) mm, and (1.70±1.76) mm; those of chest were (0.01±2.24) mm, (-0.13±2.01) mm, and (2.49±1.99) mm; and those of abdomen were (-0.05±2.41) mm, (-0.64±2.21) mm, and (1.42±2.16) mm, respectively. The fixed precisions on the X axis direction of brain, chest, and abdomen were similar. On the Y axis direction, the fixed precision of chest was the highest, and those of brain and abdomen were close to each other. On the Z axis direction, the fixed precisions of brain and abdomen were similar and were better than that of chest. There were no statistical differences in the setup errors before the first, sixth, and eleventh radiotherapy between the three parts (all P>0.05). Then the fixture was done by personalized polyurethane foam with head,neck and shoulder masks, the CTV-PTV margins of brain were 3.67 mm, 4.04 mm, and 4.59 mm; those of chest were 5.64 mm, 5.24 mm, and 5.76 mm; those of abdomen were 5.68 mm, 5.74 mm, and 5.88 mm, respectively. Conclusions　The combination of  personalized polyurethane foam with head, neck and shoulder masks has a high degree of integration. When applied in CSI, it can effectively improve the fixation accuracy for all time. It is worthy for clinical treatment. When it is in use, individualized margins should be set.

Key words:

Personalized polyurethane foam with head,neck, and shoulder masks, Craniospinal irradiation, Setup errors, Stability, Margin

摘要：

目的　分析发泡胶垫联合头颈肩面罩应用于全中枢放疗（CSI）的可行性。方法　回顾性分析2020年10月至2021年5月在中山大学肿瘤防治中心行螺旋断层全中枢放疗患者18例，其中男13例，女5例，年龄5～22岁。放疗前均行兆伏级扇形束CT（MVCT）扫描，扫描范围分别为脑部（原发灶）、胸部（第一胸椎到隆突）和腹部（第三腰椎到尾椎），所得MVCT图像与计划图像匹配，获得三维方向的摆位误差，分别记录并使用IBM SPSS 20.0统计学软件进行统计分析。结果　脑部的三维误差分别为（-0.18±1.47）mm、（-0.56±1.49）mm、（1.70±1.76）mm；胸部的三维误差分别为（0.01±2.24）mm、（-0.13±2.01）mm、（2.49±1.99）mm；腹部的三维误差分别为（-0.05±2.41）mm、（-0.64±2.21）mm、（1.42±2.16）mm。脑部、胸部和腹部在X轴方向上的固定精度相似。在Y轴方向上，胸部的固定精度最优，脑部和腹部精度接近；在Z轴方向，脑部和腹部的精度接近，且均优于胸部。分别比较第1、6、11次放疗前各部位的摆位误差，其差异均无统计学意义（均P>0.05）。应用发泡胶垫联合头颈肩面罩固定时，脑部三维方向的外扩边界分别为3.67 mm、4.04 mm、4.59 mm，胸部三维方向的外扩边界分别为5.64 mm、5.24 mm、5.76 mm，腹部三维方向的外扩边界分别为5.68 mm、5.74 mm、5.88mm。结论　发泡胶垫联合头颈肩面罩一体化程度较高，应用于全中枢放疗时，能有效提高固定精度，且固定精度不因治疗时间推进下降，值得临床推广使用，使用时需设置个体化的外扩边界。

关键词:

发泡胶垫联合头颈肩面罩, 全中枢放疗, 摆位误差, 稳定性, 外扩边界