CAJ | 학술논문

目的对胸中上段食管癌患者进行静态调强(IM RT)和容积旋转调强(VMAT)两种放疗方式的剂量学对比研究.方法对20例IMRT治疗的食管癌患者行VMAT(单弧和双弧)计划的重新设计.在单弧的VMAT计划中,对其中5例患者行不同子野间隔(4°、3°、2°)以及不同计划系统(Monaco和MasterPlan)的计划设计.比较靶区和危及器官(OAR)的剂量学差异及治疗参数.结果双弧VMAT计划各项靶区剂量学参数明显好于IMRT计划和单弧VMAT计划(P＜0.05),靶区均匀性(HI)(P＜0.05)和适形度(CI)(P＜0.05)最好.危及器官参数VMAT可在一定程度上降低OAR的受照剂量,但是IMRT对肺组织和正常组织(E-P)的低剂量保护要优于VMAT (P＜0.05);不同子野间隔的VMAT计划中,2°相对于3°和4°其OAR的受照剂量是减小的(P＜0.05),除了心脏的Dmean;不同计划系统设计的VMAT计划,以Monaco对OAR的保护为最优(P＜0.05);VMAT的机器跳数少于IMRT,而且有效节省了治疗时间.结论 VMAT方式相对于IMRT能够实现更好的靶区覆盖、均匀性和适形度,同时能降低脊髓、肺组织、心脏和E-P的受照剂量;对于VMAT来说,双弧技术、小子野角度间隔能够进一步地改善靶区和OAR的受照剂量;此外,在物理参数和优化参数一致的前提下,Monaco可以更好地保护OAR.
목적 대흉중상단식관암환자진행정태조강(IM RT)화용적선전조강(VMAT)량충방료방식적제량학대비연구.방법 대20례IMRT치료적식관암환자행VMAT(단호화쌍호)계화적중신설계.재단호적VMAT계화중,대기중5례환자행불동자야간격(4°、3°、2°)이급불동계화계통(Monaco화MasterPlan)적계화설계.비교파구화위급기관(OAR)적제량학차이급치료삼수.결과 쌍호VMAT계화각항파구제량학삼수명현호우IMRT계화화단호VMAT계화(P＜0.05),파구균균성(HI)(P＜0.05)화괄형도(CI)(P＜0.05)최호.위급기관삼수VMAT가재일정정도상강저OAR적수조제량,단시IMRT대폐조직화정상조직(E-P)적저제량보호요우우VMAT (P＜0.05);불동자야간격적VMAT계화중,2°상대우3°화4°기OAR적수조제량시감소적(P＜0.05),제료심장적Dmean;불동계화계통설계적VMAT계화,이Monaco대OAR적보호위최우(P＜0.05);VMAT적궤기도수소우IMRT,이차유효절성료치료시간.결론 VMAT방식상대우IMRT능구실현경호적파구복개、균균성화괄형도,동시능강저척수、폐조직、심장화E-P적수조제량;대우VMAT래설,쌍호기술、소자야각도간격능구진일보지개선파구화OAR적수조제량;차외,재물리삼수화우화삼수일치적전제하,Monaco가이경호지보호OAR.
Objective To compare the static intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) for mid and upper thoracic esophageal cancer.Method The data of twenty esophageal cancer patients were retrospectively re-planned with VMAT(single arc and double arcs) modality using Pinnacle treatment plan system.Five of these patients were selected again to simulate single arc plans with different segment intervals (4°,3°,2°) and re-planned on other treatment planning systems (Monaco and MasterPlan).Differences of dose distribution and treatment parameters were compared.Results In comparison to IMRT and single-VMAT (S-VMAT),Double-VMAT (D-VMAT) significantly improves the dosimetric parameters for targets(P ＜ 0.05),dose homogeneity(P ＜ 0.05) and conformity(P ＜ 0.05).Though VMAT plans were slightly better than IMRT in reducing the doses to the organs at risk (OARs),no advantage was observed in the low-dose protection of lung and E-P (P ＜ 0.05).For the VMAT plans with different segment intervals,lower OAR doses were observed using an interval of 2°(P ＜ 0.05),except for the mean dose of the heart.For the VMAT plans on different treatment planning systems,Monaco-based plans protected OARs better (P ＜ 0.05).The number of monitor units (MU) and treatment time were less in VMAT cases.Conclusions VMAT plans perform better in target coverage,dose homogeneity and conformity,and can reduce the radiation dose to the spinal cord,lungs,heart and other normal tissue than IMRT plans.The VMAT plan quality could be further improved by using double arcs and smaller segment interval.Monaco-based plans provide better OAR protections under the same conditions of physical and optimization parameters.