头颈部肿瘤自适应放射治疗的研究进展

Progress in Research of Adaptive Radiotherapy for Head and Neck Cancer

放疗已成为头颈部肿瘤治疗中重要的治疗手段之一。与三维适形放疗相比,调强放疗(Intensity ModulatedRadiation Therapy,IMRT)具有更好的适形性和均匀性,在高剂量照射肿瘤靶区的同时,减少了对周围危及器官不必要的照射。目前,在调强放疗的治疗流程中,逆向计划依据治疗之前的定位CT图像设计完成,没有考虑到患者在整个治疗过程中器官解剖结构的变化、肿瘤体积缩小及身体消瘦引起的实际接受剂量与计划剂量之间的差异。因为在IMRT技术中靶区与周围危及器官间的剂量差异较大,与常规放疗相比,解剖学上的变化对计划的实施影响更大;所以,仅根据治疗前定位CT图像实施计划设计,未充分考虑到疗程中器官解剖学变化,不但可能造成靶区欠量,而且可能造成额外的并发症。为了解决这一难题,自适应放疗(Adaptive Radiation Therapy,ART)技术应运而生,已成为放射肿瘤学界近年来的一大研究热点。所谓ART技术就是根据治疗过程中的反馈信息,分析靶区及危及器官实际解剖形状和剂量与原始治疗计划之间的差异,从而对后续治疗方案及时进行相应调整的一种治疗技术或模式。本文通过回顾国内外相关文献,并结合本单位的经验,对ART技术在头颈部肿瘤中的研究现状进行讨论。

Radiotherapy is as one of the most important treatment method for head and neck cancer.Compared with three-dimensional conformal radiotherapy,intensity-modulated radiotherapy（IMRT） has better conformal property and uniformity.Tumor target area receives higher doses of irradiation and organs at risk receive lower doses of irradiation using IMRT technology.At present,based on treatment prior to the localization of CT image design,inverse planning is completed during IMRT treatment,without regard to the difference between the actual dose and planning dose.The difference is for changes of organ anatomy,reduced tumor volume and body weight loss.Because of the difference dose between target area and surrounding organs at risk is very large in IMRT technology,anatomical changes greater impact the plan implementation compared to conventional radiotherapy.Therefore,only according to positioning CT image and not fully considering the course of organ anatomy changes,plan design is implemented.This method not only may cause target less,but also may cause additional complications.In order to solve this problem,adaptive radiotherapy（ART） is appeared,which has recently become a hot topic in the radiation oncology community.The so-called ART technology is a treatment technique or model,which analyzes the different anatomic shape and dose between the actual plan and original plan about target volume and organs at risk based on the treatment of feedback in the process,in order to adjust follow-up treatment plan timely.This paper reviews the research status of ART technology in head and neck cancer,retrospectively studying the related literature at home and abroad,combineing with the experience of our department.