CAJ | 학술논문

目的探索非小细胞肺癌(NSCLC)调强放疗(IMRT)计划设计时不同的设野方法对于计划质量的影响.方法 21例Ⅰ～Ⅲ期NSCLC患者进入本研究.IMRT采用固定野静态调强技术.每例患者采用不同的设野方法共设计3套调强计划,分别为:IMRT-7,使用等角度的7个射野,射野的入射角度分别为0°、51°、102°、153°、204°、255°、306°;IMRT-5,使用等角度的5个射野,射野的入射角度为0°、72°、144°、216°、288°;IMRT-5m,使用不等角度的5个射野,设野的方法为从前述IMRT-7的7个射野中去除2个野(若患者的病灶位于左肺,则去除角度为255°、306°的两野;若病灶位于右肺则去除角度为51°、102°的两野).IMRT计划设计时正常肺剂量限制取之于同一患者实际治疗采用的3D-CRT计划肺V5～V60.IMRT开始取处方剂量为65 Gy,根据靶区和关键器官剂量要求按每2 Gy一阶梯进行递增或递减,直至获得最佳计划.结果比较正常肺受量时发现,在V5～V25之间IMRT-5m的值较另两套计划均明显降低;V30～V40间3套计划相互间无明显差异;V45～V60间以IMRT-5计划最差;肺的平均剂量IMRT-5m最低.食管和脊髓的受量,靶区的适形性指数,以及治疗过程机器的总跳数3套计划间差异不明显.心脏V40以IMRT-5m计划的值最低.两两比较时,IMRT-5较IMRT-7明显增加了靶区的异质性指数值,而其他比较无明显差异.相比于3D-CRT,IMRT-7、IMRT-5和IMRT-5m分别可提高靶区剂量(5.1±4.6)Gy、(3.1±5.3)Gy和(5.5±4.8)Gy.结论对于NSCLC的IMRT计划设计,射野方向是重要因素,调整好设野的方向可以减少照射野数目保证甚至提高IMRT计划的质量.
목적 탐색비소세포폐암(NSCLC)조강방료(IMRT)계화설계시불동적설야방법 대우계화질량적영향.방법 21례Ⅰ～Ⅲ기NSCLC환자진입본연구.IMRT채용고정야정태조강기술.매례환자채용불동적설야방법 공설계3투조강계화,분별위:IMRT-7,사용등각도적7개사야,사야적입사각도분별위0°、51°、102°、153°、204°、255°、306°;IMRT-5,사용등각도적5개사야,사야적입사각도위0°、72°、144°、216°、288°;IMRT-5m,사용불등각도적5개사야,설야적방법 위종전술IMRT-7적7개사야중거제2개야(약환자적병조위우좌폐,칙거제각도위255°、306°적량야;약병조위우우폐칙거제각도위51°、102°적량야).IMRT계화설계시정상폐제량한제취지우동일환자실제치료채용적3D-CRT계화폐V5～V60.IMRT개시취처방제량위65 Gy,근거파구화관건기관제량요구안매2 Gy일계제진행체증혹체감,직지획득최가계화.결과 비교정상폐수량시발현,재V5～V25지간IMRT-5m적치교령량투계화균명현강저;V30～V40간3투계화상호간무명현차이;V45～V60간이IMRT-5계화최차;폐적평균제량IMRT-5m최저.식관화척수적수량,파구적괄형성지수,이급치료과정궤기적총도수3투계화간차이불명현.심장V40이IMRT-5m계화적치최저.량량비교시,IMRT-5교IMRT-7명현증가료파구적이질성지수치,이기타비교무명현차이.상비우3D-CRT,IMRT-7、IMRT-5화IMRT-5m분별가제고파구제량(5.1±4.6)Gy、(3.1±5.3)Gy화(5.5±4.8)Gy.결론 대우NSCLC적IMRT계화설계,사야방향시중요인소,조정호설야적방향가이감소조사야수목보증심지제고IMRT계화적질량.
Objective To investigate whether the change of beam set-up methods will influence the dosimetric quality of intensity modulated radiation therapy (IMRT) for non-small cell lung cancer (NSCLC).Methods Twenty-one stage Ⅰ-Ⅲ NSCLC patients were selected for this study.The technique of step and shoot was used and three different beam set-up methods were chosen for IMRT planning,including IMRT-7 with nine equal-spaced beams angled 0°,51°,102°,153°,204°,255°and 306°; IMRT-5 with five equal-spaced beams angled 0°,72°,144°,216°and 288°; and IMRT-5m which was created from IMRT-7 but excluded 2 fields (51°and 102° were omitted if there was lesion in the right lung,while 255°and 306° were excluded if there was lesion in the left lung).The dose constrains ofnormal lungs for IMRT were set according to V5-V60 of normal lungs obtained from the same patient's actually treated 3D-CRT dose volume histogram.The prescription dose for IMRT started from 65 Gy,and then escalated or decreased step by step by 2 Gy once a time until the best plan was obtained.Results For normal lung dose,IMRT-5m had lower V5-V25 than the other two groups; but there was no significant difference in V30-V40.IMRT-5 was the worst for V45-V60; and mean lung dose was lowest in IMRT-5m.Dose parameters of esophagus and spinal cord,target conformity index,and total monitor units were all similar among difference plans.IMRT-5m had lowest heart V40 compared to the other two groups.For target heterogeneity index,IMRT-5 was higher than IMRT-7,but there were no significant differences among IMRT-5m,IMRT-5 and IMRT-7.Compared to 3D-CRT,the prescription dose could be increased by (5.1 ±4.6) Gy for IMRT-7,(3.1 ±5.3) Gy for IMRT-5,and (5.5 ±4.8)Gy for IMRT-5m.Conclusion Fewer beams and modified beam angles could result in similar,even better plan quality.