呼吸门控技术在肝癌常规分割调强放射治疗中的剂量学优势研究

Dosimetric Advantages of Respiratory Gating Technique in Conventional Fractionated Intensity Modulated Radiotherapy for Liver Cancer

摘要: 目的：探讨呼吸门控技术在肝癌常规分割调强放射治疗中的靶区控制及剂量学优势。方法：选取安徽医科大学第一附属医院放疗中心治疗的10例原发性或转移性肝癌患者，所有患者均接受4D-CT扫描。分别基于30%~70%呼吸时相制定呼吸门控计划(Plan 3~10)及自由呼吸下的全时相常规放疗计划(Planall)，处方剂量为63 Gy/21次，采用VMAT技术。比较两种计划在ITV、PTV体积、靶区剂量、肝脏及其他危及器官剂量学参数，并记录机器跳数(MU)及单次治疗耗时。结果：与常规放疗计划相比，呼吸门控计划的ITV与PTV体积显著减小(P < 0.05)，肝脏Dmean及V5、V10、V20、V30明显降低(P < 0.05)。呼吸门控计划的MU及单次治疗时间显著高于常规计划(P < 0.05)。结论：在肝癌常规分割IMRT/VMAT治疗中，呼吸门控技术可有效缩小靶区体积、降低危及器官受照剂量，但会增加治疗时间与机器负荷，临床应用中需在剂量学获益与治疗效率、患者耐受性之间进行权衡。

Abstract: Objective: To investigate the dosimetric advantages of respiratory gating in conventionally fractionated IMRT/VMAT for liver cancer. Methods: Ten patients with primary or metastatic liver cancer treated at the Radiation Oncology Center of the First Affiliated Hospital of Anhui Medical University were enrolled. All patients underwent 4D-CT scanning. A respiratory-gated plan based on 30%~70% respiratory phases (Plan 3~10) and a free-breathing full-phase plan (Planall) were generated with a prescription dose of 63 Gy in 21 fractions using VMAT. Target volumes, dosimetric parameters of organs at risk, monitor units (MU), and treatment time were compared. Results: Compared with the free-breathing plan, respiratory-gated plans significantly reduced ITV and PTV volumes (P < 0.05), decreased liver dose parameters and doses to other organs at risk (P < 0.05), while increasing MU and treatment time (P < 0.05). Conclusion: In the conventional fractionated IMRT/VMAT treatment of liver cancer, respiratory gating technology can effectively reduce the volume of the target area and reduce the irradiation dose of endangered organs, but it will increase the treatment time and machine load. In clinical application, it is necessary to make a tradeoff among the dosimetric benefit, treatment efficiency and patient tolerance.