CAJ | 학술논문

目的：应用螺旋断层放疗机（Tomo therapy）自带的兆伏级CT（MVCT）影像引导，测定并分析采取面网固定方式的头颈部肿瘤患者的摆位误差，并依此计算CTV-PTV外扩Margin值的大小。方法对34例采取面网固定装置的头颈部肿瘤患者，每次治疗前均行MVCT扫描，将扫描所得MVCT图像与定位图像（kVCT）行靶区位置配准，分析患者左右（x）、头脚（y）、腹背（z）和横断面旋转（Roll）方向的误差值，根据公式M＝2．5∑＋0．7σ计算出合理的CTV-PTV外扩Margin值。结果34例患者共行640次MVCT扫描，线性误差在x、y、z方向的系统误差±随机误差分别为：（-0．15±0．55） mm、（0．30±0．56） mm、（0．35±0．71）mm；在Roll方向的旋转误差为（-0．07±0．52）°。 CTV-PTV外放边界在x、y、z三个方向Margin值分别为3．31 mm、5．32 mm和3．35 mm。结论通过对摆位误差的分析为CTV-PTV外扩边界提供了理论依据，为精确放疗提供必要的质量保证。
목적：응용라선단층방료궤（Tomo therapy）자대적조복급CT（MVCT）영상인도，측정병분석채취면망고정방식적두경부종류환자적파위오차，병의차계산CTV-PTV외확Margin치적대소。방법대34례채취면망고정장치적두경부종류환자，매차치료전균행MVCT소묘，장소묘소득MVCT도상여정위도상（kVCT）행파구위치배준，분석환자좌우（x）、두각（y）、복배（z）화횡단면선전（Roll）방향적오차치，근거공식M＝2．5∑＋0．7σ계산출합리적CTV-PTV외확Margin치。결과34례환자공행640차MVCT소묘，선성오차재x、y、z방향적계통오차±수궤오차분별위：（-0．15±0．55） mm、（0．30±0．56） mm、（0．35±0．71）mm；재Roll방향적선전오차위（-0．07±0．52）°。 CTV-PTV외방변계재x、y、z삼개방향Margin치분별위3．31 mm、5．32 mm화3．35 mm。결론통과대파위오차적분석위CTV-PTV외확변계제공료이론의거，위정학방료제공필요적질량보증。
Objective To investigate the setup errors of head and neck tumor patients with head mask-ing by TomoTherapy with megavoltage CT (MVCT),and to measure the CTV -PTV margins.Methods There were 34 patients with head and neck tumor .All patients had received MVCT scanning before radiation was deliv-ered.The MVCT images were registered with the kilovoltage CT (kVCT)images,the setup errors of the left -right (x),anterior-posterior(y),superior-inferior(z)and transverse profile rotation(Roll)were obtained by matc-hing MVCT with kVCT,followed by calculating the reasonable CTV -PTV margins with the formula M=2.5∑+0.7σ.Results Six hundred and forty MVCT images in total were received for the patients ,the systemic ±random errors in x,y,z and Roll directions were ( -0.15 ±0.55) mm,(0.30 ±0.56) mm,(0.35 ±0.71) mm and (-0.07 ±0.52)°,the CTV-PTV margin in x,y and z directions were 3.31 mm,5.32 mm and 3.35 mm.Con-clusion we demonstrate a theoretic foundation for our CTV -PTV margins in head and neck tumor patients by analyzing the setup errors ,and it also can provide necessary quality assurance for precise radiation .