鼻咽癌螺旋断层调强放疗图像引导策略(英文)

Image-guided Strategy of Intensity-modulated Radiotherapy in Helical Tomography for Nasopharyngeal Carcinoma

【目的】分析系统误差校正前后摆位误差的差异。为了确定在鼻咽癌治疗中最合适的影像引导策略,我们使用不同的扫描范围和影像引导频率对鼻咽癌(NPC)患者进行螺旋断层放疗(HT)。【方法】选择2019年10月至2020年02月在中山大学肿瘤防治中心接受HT治疗的NPC患者15例。每次治疗前均进行高压计算机断层扫描(MVCT)。放疗5次后,进行系统误差校正,调整摆位中心。采集了系统误差修正前后的摆位误差,以及不同扫描范围、不同扫描频率下的摆位误差进行了分析比较。【结果】系统误差校正前后摆位误差比较,左-右(LR)、上-下(SI)、前-后(AP)方向摆位误差差异有统计学意义(P<0.05);“鼻咽+颈”、“鼻咽”不同扫描范围比较,偏航旋转误差差异有统计学意义(P<0.05)。经系统误差校正后的每日扫描频率与每周扫描频率比较,AP方向差异有统计学意义(P<0.05)。【结论】在鼻咽癌放射治疗中,根据前5次摆位误差可以纠正系统误差,然后选择小范围扫描进行每天的图像引导放射治疗。

【Objective】This study aimed to analyze the difference in setup error before and after correction of systematic error. To determine the most appropriate image-guided strategy during HT treatment, we use different scanning ranges and image-guidance frequencies in patients with nasopharyngeal carcinoma(NPC) treated with helical tomotherapy(HT).【Methods】Fifteen patients with NPC who received HT treatment in Sun Yat-sen University Cancer Center from October 2019 to February 2020 were selected. Megavoltage computed tomography(MVCT) scanning was performed before each treatment. After five times of radiotherapy, system-error correction was performed to adjust the setup center. The setup errors before and after the correction of systematic errors, as well as the setup errors of different scanning ranges and different scanning frequencies, were collected for analysis and comparison.【Results】When comparing the setup errors before and after the correction of systematic error, the differences in setup errors in the left –right(LR), superior–inferior(SI), and anterior–posterior(AP) directions were statistically significant(P<0.05).The different scanning ranges of "nasopharynx + neck" and "nasopharynx" were compared, and a statistically significant difference was found in yaw rotational errors(P<0.05). In the comparison of daily and weekly scan frequency after system-error correction, a significant difference was found in AP direction(P<0.05).【Conclusion】During radiotherapy for NPC, the systematic error can be corrected according to the first five setup errors, and then small-scale scanning was selected for image-guided radiotherapy every day.