【摘要】 目的:研究调强放射治疗前后腮腺的实际照射剂量变化。方法:入组18例进行调强放射治疗的鼻咽癌患者。治疗前后各扫描一组CT图像。临床医生在这两组图像中分别勾画出腮腺及外轮廓。通过图像配准技术,把治疗结束时的腮腺及外轮廓映射至治疗前的计划CT图像上。经过外轮廓进行修正后,使用治疗前计划计算出治疗后剂量。分析腮腺治疗前后在体积和空间位置变化时引起的剂量学的变化。结果:左右腮腺治疗前后体积,D50,V42数值均有较大的变化。前后配对t检验结果,左右体积为t=7.29(P<0.01),t=7.65(P<0.01);左右D50为t=4.09(P<0.01),t=4.54(P<0.01);左右V42为t=4.95(P<0.01),t=4.36(P<0.01)。均有统计学意义。结论:放射治疗前后腮腺体积与空间位置变化的条件下,腮腺的剂量与治疗前的计划剂量有很大差异。而且剂量基本呈现增大的趋势,需要正确的评估其剂量,才能对于腮腺的功能给出合理的估计。更多还原

【Abstract】 Objective: To investigate the dose changes of parotid glands between before and after intensity- modulated radiotherapy( IMRT) for nasopharyngeal carcinoma( NPC). Methods: 18 patients with NPC were treated by IMRT. Computed tomography( CT)was acquired before and after treatment. The each slide of parotid glands was contoured independently by physician. Then the after treatment contour of parotid glands and body external contour mapped onto the before treatment CT image series by Pinnacle planning system. The dose of parotid glands of after treatment was computed using the original plan with body external contour correction and compared to the dose of original plan. Results: There were significant in statistics to parotid glands volume,dose of 50% volume of parotid glands,percent volume of parotid glands at 42 Gy. Left and right volume of parotid glands were t = 7. 29( P < 0. 01); t =7. 65( P < 0. 01),respectively. Left and right dose of 50% volume of parotid glands were t = 4. 09( P < 0. 01),t = 4. 54( P <0. 01),respectively. Left and right percent volume of parotid glands at 42 Gy were t = 4. 95( P < 0. 01); t = 4. 36( P < 0. 01),respectively. Conclusion: The volumes of parotid glands decrease remarkably during radiotherapy. The geometry and spatial location have significant change. There are significantly dose changes of both parotid glands comparing dose of original plan. The dose of parotid glands is almost increased. If we want evaluate the function of parotid glands,we must get the true dose of parotid glands更多还原