【作者】 石莉莉；

【导师】 李国文；

【作者基本信息】 郑州大学 ， 放射医学， 2012， 硕士

【摘要】 目的分析和比较三维适形(3D-CRT)和调强适形(IMRT)计划在Ⅲ期中央型非小细胞肺癌(NSCLC)中靶区以及危及器官的剂量分布特点,以推断应用于Ⅲ期中央型非小细胞肺癌(NSCLC)治疗中的最优计划。方法选取32例Ⅲ期中央型非小细胞肺癌(NSCLC)患者,采用CMS公司XIO三维治疗计划系统对每例患者分别设计3D-CRT和IMRT两个治疗计划,所有计划均由同一位物理师制定和两位放疗医师评估完成。处方剂量均为60Gy/2G/30次。所有计划均使95%靶区体积达到处方剂量要求。比较两种计划的PTV的平均剂量(Dmean)以及95%、100%、110%的处方剂量包绕PTV的体积百分比、靶区适形指数(CI)、靶区均匀指数(HI),肺V5、肺V10、肺V20、肺V30、肺V40、肺平均剂量,心脏V30、心脏V40以及心脏的平均剂量(Dmean),脊髓最大受照剂量和平均受照剂量(Dmean),食管V35、食管V55和食管平均剂量(Dmean),通过剂量体积直方图(DVH)评价两种计划的靶区以及危及器官如正常肺组织、心脏、脊髓、食管的剂量分布特点。结果(1)IMRT不仅在靶区剂量分布方面有优势,在靶区的适形度上也较3D-CRT有明显的提高,但靶区均匀指数较3D-CRT差。(2)IMRT在肺V5较3D-CRT明显升高,且有统计学差异(P<0.05)。而IMRT在肺V10、肺V20、肺V30、肺V40以及肺平均剂量较3D-CRT明显减少了肺组织受高剂量照射的体积,其中肺V20降低最明显,且均有统计学差异(P<0.05)。(3)从心脏V30、心脏V40及心脏的平均剂量的分析来看,IMRT比3D-CRT在降低心脏受照剂量-体积方面更有优势,且有统计学差异(P<0.05)。(4) IMRT减少了脊髓最大受照剂量和平均受照剂量,较3D-CRT降低了脊髓的受量。且两者有统计学差异(P<0.05)但两种计划均未超出脊髓的最大耐受剂量。(5)在食管V35、食管V55和食管平均剂量上IMRT较3D-CRT在降低食管受照剂量上更有优势,且两者有统计学差异(P<0.05)。结论IMRT能有效提高Ⅲ期中央型非小细胞肺癌的靶区剂量分布,在提高靶区适形度的同时,降低了危及器官如正常肺组织、心脏、脊髓、食管的受照剂量,较3D-CRT有明显优势。更多还原

【Abstract】 ObjectiveTo analyze and compare the characteristics of dose distribution between the three-dimensional conformal radiotherapy(3 D-CRT) and the intensity modulated radiotherapy(IMRT) in stageⅢcentral type non-small cell lung cancer (NSCLC) and to understand which is the optimal plan.Methods32 patients with stageⅢcentral type NSCLC were performed 3D-CRT and IMRT with CMS XIO three-dimensional treatment plan system, respectively. All plans were finished by the same medical physicist, and were evaluated by two radiation oncologist. The prescription dose of 3D-CRT and IMRT was 60Gy/2 Gy /30f. The mean dose delivered to the planning target volume(PTV), the prescribed dose of 95%,100% and 110% occupied the volume percentage of PTV, the target of conformity index and homogeneity index, lungV5, lungV10, lungV20, lungV30, lungV40, mean lung dose, heart V30, heart V40, mean heart dose, the maximum and average exposure dose of spinal cord, the average exposure dose of esophagus, esophagus V35 and esophagus V55 were calculated and analyzed by the dose-volume histogram (DVH) which is obtained the characteristics of target volume and organs at risk (such as:lung, heart, spinal cord and esophagus) in dose distribution.Result(1) Compared with 3D-CRT, IMRT is not only superior in the dose distributions of target volume, but also significantly improves target dose conformity. But IMRT has lower target homogeneity index than 3D-CRT. (2) IMRT have higher lung V5 than 3D-CRT, which is statistically significant (P< 0.05). However, High dose exposure volume of the lung to IMRT in the lung V10, lung V20, lung V30, lung V40 and mean lung dose decreased more than 3D-CRT, especially in the lung V20. The results have statistical difference(P< 0.05). (3) The analysis of heart V30, heart V40 and mean heart dose informed that IMRT has more advantages than 3D-CRT in decreasing the heart exposure dose (P< 0.05). (4) IMRT can significantly decrease the maximum exposure dose and average exposure dose to the spinal cord compared with 3D-CRT(P < 0.05), but neither of the two plans exceed the maximum tolerance dose of spinal cord. (5) IMRT is significantly superior to 3D-CRT in the average exposure dose of esophagus, esophagus V35 and esophagus V55(P< 0.05).ConclusionsCompared with 3D-CRT radiation technique, IMRT effectively enhances the target volume and improve target dose conformity, simultaneously highlights the protective advantages in the organs at risk (such as:lung, heart, spinal cord and esophagus) for stage III central type non-small cell lung cancer.更多还原