对局部晚期NPC患者进行IMRT时通过Pinnacle计划系统设置不同的最大子野数的效果

Effects of setting different maximum number of subfields by Pinnacle plan ning system in locally advanced NPC patients during IMRT

目的:探讨并分析对局部晚期鼻咽癌(NPC)患者进行调强放疗(IMRT)时通过Pinnacle计划系统设置不同的最大子野数的效果及对其放疗指标的影响。方法:选择2018年1月至2019年1月期间在广东医科大学附属医院肿瘤中心采用Pinnacle 9.8放射治疗计划系统进行IMRT计划设计的24例局部晚期NPC患者作为研究对象。在对这些患者进行IMRT前,采用Pinnacle计划系统对其放疗靶区进行逆向优化设计,将最大子野数分别设置为60、80、100、120,并依次将其命名为plan1、plan2、plan3、plan4。比较在plan1、plan2、plan3、plan4下对患者进行IMRT时其各项放疗指标,然后找出最优的最大子野数。结果:与在plan1、plan2下对这24例患者进行IMRT相比,在plan3、plan4下对其进行IMRT时其靶区的CI均更大,其靶区的HI均更小,P<0.05。与在plan3、plan4下对这24例患者进行IMRT相比,在plan1和plan2下对其进行IMRT时其PGTVnd的Dmean均更高,P<0.05。与在plan1、plan2下对这24例患者进行IMRT相比,在plan3、plan4下对其进行IMRT时其脊髓、左眼球、左晶体、右晶体、右视神经、视交叉和右侧颞叶的Dmax均更低,P<0.05。与在plan1、plan2下对这24例患者进行IMRT相比,在plan3、plan4下对其进行IMRT时其机器的总跳数更多,其治疗的时间更长,P<0.05。结论:对局部晚期NPC患者进行IMRT时,通过Pinnacle计划系统设置不同的最大子野数对其靶区的CI、HI、危及器官的照射剂量、治疗的时间等均会产生不同的影响。与在最大子野数为60、80、120的情况下对此类患者进行IMRT相比,在最大子野数为100的情况下对进行IMRT的效果最佳。

objective:to explore and analyze the effect of setting different maximum subfield number through Pinnacle planning system in IMRT for patients with locally advanced nasopharyngeal carcinoma(NPC)and its influence on the radiotherapy index.Methods:from January 2018 to January 2019,24 patients with locally advanced NPC who were IMRT planned by Pinnacle 9.8 radiotherapy planning system in the tumor center of affiliated hospital of guangdong medical university were selected as the research objects.Before IMRT was performed on these patients,the Pinnacle planning system was used to reverse optimize the radiotherapy target,and the maximum subfield number was set to 60,80,100,and 120,respectively,and was successively named plan1,plan2,plan3,and plan4.The radiotherapy indexes of patients undergoing IMRT under plan1,plan2,plan3 and plan4 were compared,and the optimal maximum subfield number was found.Results:compared with IMRT on plan1 and plan2 in these 24 patients,IMRT on plan3 and plan4 had larger target CI and smaller target HI(P<0.05).Compared with IMRT on plan3 and plan4 in these 24 patie nts,Dmean of PGTVnd was higher when IMRT was performed on plan1 and plan2(P<0.05).Compared with IMRT under plan1 and plan2 in these 24 patients,Dmax of spinal cord,left ocular ball,left crystal,right crystal,right optic nerve,optic chiasm and right temporal lobe were all lower when IMRT was performed under plan3 and plan4(P<0.05).Compared with IMRT for these 24 patients under plan1 and plan2,IMRT under plan3 and plan4 had a higher total number of machine jumps and a longer treatment time(P<0.05).Conclusion:when IMRT is performed on patients with locally advanced NPC,setting different maximum subfield Numbers through the Pinnacle planning system will have different effects on the target area CI,HI,irradiation dose of organs at risk and treatment time.Compared with IMRT in patients with a maximum subfield number of 60,80,and 120,IMRT in patients wi th a maximum subfield number of 100 had the best effect.