鼻咽癌调强放疗患者腮腺体积变化的影像学动态评估

摘要

Objective To study parotid volume variations with CT and MRI during the nasopharyngeal carcino-ma intensity modulated radiation therapy (IMRT). Methods Forty-two cases of patients with nasopharyngeal carcino-ma were treated by IMRT, CT and MRI scan were all acquired 1 week before radiotherapy, radiotherapy in the first week, the first 3 weeks, 5 weeks, 7 weeks, after the end of radiotherapy and a month. On each image delineated con-tours of the parotid gland and then calculated its volume by TPS(Treatment planning system)workstation,Using SPSS software to analyze the parotid volume change comparisons over time. Results Radiotherapy in the first week of CT and MRI scans measured to the parotid gland volume compared with 1 week before radiotherapy, there were no statis-tically significant difference (P>0.05); Radiotherapy in 3 weeks, 5 weeks, 7 weeks and radiotherapy after 1 month of CT and MRI scans measured to parotid gland volume compared with 1 week before radiotherapy, the difference had statistical significance (P<0.05); Both CT and MRI measured in different periods of the parotid gland volume differ-ence had no statistical significance (P>0.05). Conclusion Intensity modulated radiation therapy, there is a big change of the volume of parotids, radiotherapy plan should be dynamically adjusted.%目的：本研究拟通过CT和磁共振成像（MRI）探讨鼻咽癌调强放疗患者腮腺体积随剂量-时间的动态变化规律和特征。方法随机选取病理确诊鼻咽癌患者42例按入组标准进行调强放疗，在放疗前1周内，放疗中第1周、第3周、第5周、第7周以及放疗结束后1个月行腮腺CT及MRI扫描，将图像导入计划系统（TPS）工作站，逐层勾画腮腺并计算体积。采用SPSS软件分析比较不同时间点的腮腺体积变化，同时比较CT和MRI 2种检查方法对腮腺体积变化评估结果的差异。结果放疗中第1周CT、MRI扫描所测到的腮腺体积与放疗前1周对比，差异均无统计学意义（P＞0．05）；放疗中第3周、第5周、第7周以及放疗结束后1个月CT、MRI扫描所测到的腮腺体积与放疗前1周对比，差异均有统计学意义（P＜0．05）；CT和MRI 2种扫描方法各时间点所测到的腮腺体积差异经配对t检验均无统计学意义（P＞0．05）。结论鼻咽癌调强放疗过程中，患者腮腺体积存在着较大的变化，放疗计划在治疗过程中应当进行动态调整，以降低出现肿瘤脱靶欠剂量和危及器官的过剂量照射等可能。