论文部分内容阅读
目的:比较插植照射和调强照射两种照射方式在胸部肿瘤靶区内的剂量分布和肺受照剂量.方法:选取18例接受插植放疗的胸部肿瘤病人,分别制作计划靶区(PTV)处方剂量为120Gy的调强计划和临床靶区(CTV)处方剂量为120Gy的插植计划.计算D95(靶区95％体积的受照剂量)、D90、D50、D30、靶区倍率因子曲线和肺v20、V0.结果:调强放疗和插植放疗计划的肺v20分别为(21.50±16.89)％和(33.73±12.12)％(P＜0.05),肺V30分别为(14.63±13.29)％和(29.86±12.55)％(P＜0.05).调强计划PTV和插植计划CTV的D95无统计学差异(P＞0.05),D90、D50和D30具有统计学差异(P＜0.05).结论:调强放疗的靶区剂量分布比较均匀,而插植照射的靶区剂量分布呈高梯度变化且越靠近靶区中心剂量越高;在内照射三维计划系统中设计内照射计划时,靶区剂量均匀性验收要求应该区别于外照射方式.“,”Objective To compare the dose distribution in target areas and lung dose between interstitial irradiation therapy and intensity-modulated radiotherapy (IMRT) for thoracic neoplasms.Methods Eighteen patients with thoracic neoplasms receiving interstitial irradiation were selected.For each patient,the interstitial irradiation therapy plan with 120 Gy prescribed dose for clinical target volume (CTV) and the IMRT plan with 120 Gy for planning target volume were designed,respectively.The dose of the 95％ volume of the target area (D95),D90,D50,D30,multiplying factor curve,and the V20 and V30 of lung were calculated.Results Significant differences between IMRT plan and interstitial irradiation therapy plan were found in the lung-V20 [(21.50±16.89)％ vs (33.73±12.12)％] and lung-V30 [(14.63±13.29)％ vs (29.86±12.55)％] (P＜0.05).The comparison between CTV of interstitial irradiation therapy plan and PTV of IMRT plan also showed that statistical differences was not found in D95 (P＞0.05),but in D90,D50 and D30 (P＜0.05).Conclusion The homogeneity index of dose distribution in target areas in IMRT was higher compared to that in interstitial irradiation therapy.The dose in interstitial irradiation therapy was higher with closer to the center of CTV.The dose uniformity in target areas and acceptance requirements of irradiation plan designed in three-dimensional planning system should be distinguished from the external irradiation mode.