基于MVCT图像引导放疗的分次间和分次内头颈部肿瘤外扩边界研究  

Inter-and intra-fractional extension of head and neck tumors based on MVCT image-guided radiotherapy

作　　者：李宗泰 林志悦 姚文燕[1] 迟锋[1] 许森奎[1] Li Zongtai;Lin Zhiyue;Yao Wenyan;Chi Feng;Xu Senkui(State Key Laboratory of Oncology in South China,Guangdong Provincial Clinical Research Center for Cancer,Department of Radiation,Sun Yat-sen University Cancer Center,Guangzhou 510060,China)

机构地区：[1]华南恶性肿瘤防治全国重点实验室,广东省恶性肿瘤临床医学研究中心,中山大学肿瘤防治中心放疗科,广东广州510060

出　　处：《实用肿瘤杂志》2025年第2期167-171,共5页Journal of Practical Oncology

基　　金：广东省医学科学技术研究基金(A2017613);广东省食管癌研究所科技计划(Q202107);中山大学肿瘤防治中心青年优创项目(PT21020101)。

摘　　要：目的探讨在兆伏CT(mega voltage CT,MVCT)图像引导技术下,应用螺旋断层调强放疗(helical tomotherapy,HT)治疗头颈部肿瘤时在分次间和分次内相对应的外扩边界大小。方法选取中山大学肿瘤防治中心2017年12月至2018年2月收治的10例头颈部肿瘤患者进行HT治疗,每例每周1次进行治疗前MVCT扫描,图像配准后记录分次间误差和修正摆位误差后再进行1次扫描与配准,获得残留误差数据,治疗后重新扫描与配准,得出分次内误差,再根据公式得出计划靶区(planning target volume,PTV)外扩边界MarginPTV。结果每例患者扫描5次,共50次,得到X(左右)、Y(前后)和Z(头脚)轴方向上的摆位误差。Z轴平均分次间误差为2.80 mm。分次间误差及其在线校准后的残留误差在3个方向上比较,差异均具有统计学意义(均P<0.05)。3个方向上的分次内误差与残留误差比较,差异均无统计学意义(均P>0.05)。X、Y和Z轴方向上,分次间误差的MarginPTV分别为2.279、2.447和1.805 mm,残留误差的MarginPTV为0.853、0.963和0.917 mm,分次内误差的MarginPTV为1.015、0.979和0.710 mm。结论Z轴分次间误差普遍较大。每次放疗前进行图像引导,可大幅缩小放疗计划的MarginPTV。头颈部放疗计划的MarginPTV需要综合考虑患者图像引导后残留误差和分次内误差。Objective To investigate the inter-and intra-fractional expansion boundaries of head and neck tumors treated with helical tomotherapy(HT)under the guidance of mega voltage CT(MVCT).Methods Ten patients with head and neck tumors treated with HT at Sun Yat-sen University Cancer Center from December 2017 to February 2018 were selected.Each patient underwent MVCT scan before treatment once a week.After image registration,the inter-fractional error data were recorded and corrected,and the residual error data were scanned and registered again.The intra-fractional errors were obtained,and the planning target volume(PTV)margin was calculated.Results Each patient was scanned 5 times for a total of 50 times,and the setup errors in the left-right(X-axis),anterior-posterior(Y-axis),and superior-inferior(Z-axis)directions were obtained.The average inter-fractional error in the Z axis was 2.80 mm.There were significant differences in the inter-fractional error and the residual error after online calibration in the three directions(all P<0.05).There were no significant differences in the intra-fractional error and the residual error in the three directions(all P>0.05).The PTV margins for the inter-fractional errors in the X-,Y-,and Z-axis directions were 2.279,2.447,and 1.805 mm,respectively,while the PTV margins for the residual errors were 0.853,0.963,and 0.917 mm,and the PTV margins for the intra-fractional errors were 1.015,0.979,and 0.710 mm.Conclusions The inter-fractional setup errors in the Z direction were generally large.The image guidance before each radiotherapy can greatly reduce the PTV margin of radiotherapy plan.The residual errors after image-guided radiotherapy and the intra-fractional errors should be considered comprehensively in the planning of head and neck radiotherapy.

关 键 词：头颈部肿瘤 螺旋断层调强放疗 外扩边界 分次间误差 分次内误差 

分 类 号：R73[医药卫生—肿瘤]