论文部分内容阅读
放射治疗是鼻咽癌的首选治疗手段。调强适形放疗(IMRT)既满足了鼻咽癌临床生物学行为对靶区的要求,同时满足了对头颈部重要器官功能保护的要求,在鼻咽癌的治疗中有着其它治疗无可比拟的优势,已成为鼻咽癌放疗的主流技术。靶区确定和勾画是IMRT的重点:大体肿瘤靶区包括鼻咽原发肿瘤及转移淋巴结;临床靶区根据受累的危险程度的不同分为高危区和低危区,不同的靶区给予不同的照射剂量。同常规放疗技术相比,IMRT提高了肿瘤区剂量,并使肿瘤区的剂量分布更加均匀,同时降低了正常组织受量,尤其在保护腮腺功能方面取得了理想的效果,有效缓解了鼻咽癌放疗后因唾液分泌不足造成的口干症状。而对于保护腮腺功能的限制剂量目前尚无定论。总结其临床应用结果,IMRT提高了肿瘤局控率,远处转移成为治疗失败主要原因,需采取综合治疗提高疗效。在采取何种方法降低肿瘤复发率的问题上仍存在争议。因鼻咽癌IMRT开展较晚,长期疗效有待进一步观察。IMRT目前存在的问题包括低剂量放射超敏感性造成的正常组织生物效应增加;分次照射时间延长导致的肿瘤区相对剂量率降低;不同单位在靶体积划分和勾画方面的差异等。在运用多种影像融合技术提高靶区勾画精确性以及利用乏氧细胞示踪技术实现生物适形等方面仍需近一步研究。
Radiation therapy is the treatment of choice for nasopharyngeal carcinoma. IMRT meets the requirements of the target area for clinical biological behavior of nasopharyngeal carcinoma and fulfills the requirements for functional protection of vital organs of the head and neck. There are other treatments that are unparalleled in the treatment of nasopharyngeal carcinoma The advantage has become the mainstream of nasopharyngeal carcinoma radiotherapy technology. Target area identification and delineation are the focuses of IMRT: The gross tumor target area includes the primary nasopharyngeal tumor and the metastatic lymph node. The clinical target area is divided into high-risk area and low-risk area according to the degree of risk involved. Different target areas are given different Irradiation dose. Compared with the conventional radiotherapy, IMRT increased the dosage of the tumor area, and made the dose distribution in the tumor area more uniform. At the same time, IMRT reduced the amount of normal tissue, especially in the protection of the parotid gland function, which effectively relieved the nasopharyngeal carcinoma Irritation caused by saliva after oral administration of dry mouth symptoms. And for the protection of parotid gland function of the dose is currently inconclusive. Summarized its clinical application results, IMRT increased tumor control rate, distant metastasis as the main reason for treatment failure, need to take comprehensive treatment to improve the curative effect. There is still controversy over what approach to reduce the rate of tumor recurrence. Due to nasopharyngeal carcinoma IMRT late, long-term efficacy remains to be further observed. The current problems of IMRT include the increase of biological effects of normal tissues caused by low-dose radiation hypersensitivity, the decrease of the relative dose rate in tumor area caused by prolonged irradiation time, and the differences in target volume division and delineation by different units. In the use of a variety of image fusion technology to improve the accuracy of the target area outlined and the use of hypoxic cell tracing technology to achieve such aspects of biological conformal still need further study.