【摘要】 目的 分析鼻咽癌、乳腺癌、宫颈癌患者在兆伏级CT(MVCT)影像引导下螺旋断层放射治疗的摆位误差，计算鼻咽癌、乳腺癌、宫颈癌患者相应的靶区外扩边界，从而为临床靶区到计划靶区（CTV-PTV）的确定提供依据。方法 选取2022年10月至2023年9月于广东省中医院放疗中心行螺旋断层放射治疗的90例患者，其中鼻咽癌、乳腺癌、宫颈癌患者各30例。治疗前，采用MVCT对所有患者进行摆位误差分析，鼻咽癌、乳腺癌、宫颈癌患者分别采集900次、870次、900次MVCT图像，通过与计划CT对比得到摆位误差，计算不同部位肿瘤在左右（x）、头脚（y）、腹背（z）方向的误差平均值（∑）及标准差（δ），并确定靶区外扩的边界值。结果 鼻咽癌患者的摆位误差为+x(1.45±1.12)、-x(1.50±1.56)、+y(2.01±1.51)、-y(1.65±1.25)、+z(2.10±1.26)、-z(1.25±1.13)mm，乳腺癌患者的摆位误差为+x(3.55±2.52)、-x(3.56±3.13)、+y(3.15±3.32)、-y(3.12±3.02)、+z(5.48±3.01)、-z(3.32±2.46)mm，宫颈癌患者的摆位误差为+x(3.02±2.35)、-x(3.12±2.32)、+y(3.11±2.56)、-y(3.04±2.86)、+z(5.02±2.89)、-z(3.12±2.13)mm，鼻咽癌患者6个方向的外放边界为（2,2,3,3,3,3）mm，乳腺癌患者6个方向的外放边界为（3,3,7,7,8,5）mm，宫颈癌患者6个方向的外放边界为（3,3,7,7,7,4）mm。结论 螺旋断层放射治疗时，鼻咽癌患者摆位误差小于乳腺癌与宫颈癌患者，乳腺癌患者的摆位误差最大，通过摆位误差可确定靶区外扩边界，改善患者的放射治疗质量。更多还原

【Abstract】 Objective To analyze the positioning error of tomotherapy with megavoltage computed tomography(MVCT) image guidance for patients with nasopharyngeal carcinoma, breast cancer, and cervical cancer, and calculate the corresponding target expansion boundary of nasopharyngeal carcinoma, breast cancer and cervical cancer patients, so as to provide a basis for the determination of clinical target volume to planned target volume(CTV-PTV). Methods With the random selection of 90patients visited to the radiotherapy center of Guangdong Provincial Hospital of Traditional Chinese Medicine for spiral tomotherapy from October 2022 to September 2023, including 30patients with nasopharyngeal cancer, 30 patients with breast cancer, and 30 patients with cervical cancer, before treatment, MVCT was used to analyze the positioning error of all patients.MVCT images were collected 900, 870, and 900 times for nasopharyngeal cancer, breast cancer,and cervical cancer patients, respectively. The positioning error was obtained by comparing with the planned CT. The average error( ∑) and standard deviation(δ) in the left and right(x), head and foot(y), and front and back(z) directions of the tumors at different sites were calculated, and the boundary value of the target area expansion was determined.Results The positioning errors of nasopharyngeal carcinoma patients were +x(1.45±1.12),-x(1.50±1.56), +y(2.01±1.51),-y(1.65±1.25), +z(2.10±1.26),-z(1.25±1.13) mm. The positioning errors of breast cancer patients were +x(3.55±2.52),-x(3.56±3.13), +y(3.15±3.32),-y(3.12±3.02), +z(5.48±3.01),-z(3.32±2.46) mm. The positioning errors of cervical cancer patients were +x(3.02±2.35),-x(3.12±2.32), +y(3.11±2.56),-y(3.04±2.86),+z(5.02±2.89),-z(3.12±2.13) mm. The external radiation boundary of nasopharyngeal carcinoma patients in six directions was(2, 2, 3, 3, 3, 3) mm, that of breast cancer patients in six directions was(3, 3, 7, 7, 8, 5) mm, and that of cervical cancer patients in six directions was(3, 3, 7,7, 7, 4) mm. Conclusions In tomotherapy, the positioning error of nasopharyngeal carcinoma patients was smaller than that of tumor patients in other parts, and the positioning error of breast cancer patients was the largest. Through the positioning error, the external expansion boundary of the target area was determined to improve the quality of radiotherapy for patients.更多还原