Monaco治疗计划系统中参数设置对容积旋转调强放射治疗计划质量的影响

Impacts of Parameter Settings on the Quality of Plans for the Volumetric Modulated Arc Therapy with Monaco Treatment Planning System

目的研究Monaco治疗计划系统中不同参数设置对容积旋转调强放射治疗(VMAT)计划质量的影响,得出更合理的治疗计划参数设置以提高VMAT治疗质量。方法 2010年15月间治疗3例患者,为食管癌、宫颈癌和鼻咽癌各1例,分别设置不同的计划参数进行容积旋转调强计划优化,通过多种评估指标比较各VMAT计划质量的差异,得出临床所需的MSC、MSS、SSF、Sm、MMS和MDR共6个治疗计划参数对VMAT治疗质量的影响。结果 MSC、MSS和SSF的3个参数对VMAT治疗质量不产生影响,有影响的Sm、MMS和MDR参数中,随着Sm和MMS值的增大,VMAT计划的剂量分布逐渐变差,但控制点数、机器跳数和照射时间均逐渐减小;随着MDR值增大,VMAT治疗的剂量分布先逐渐变差后不变,控制点数和机器跳数均是先增大后不变,而照射时间是先减小后不变。结论 Sm、MMS和MDR3个参数对VMAT计划质量有较大影响,对不同的患者,设置合适的Sm、MMS和MDR值对提高计划质量非常重要。

Objective To investigate the impacts of p ar ameter settings on the quality of plans for the volumetric modulated arc therapy （VMAT） with Monaco treatment planning system. Methods Three p atients who underwent VMAT from January to May 2010 were selected. The planning optimizations were processed by setting different planning parameters, including MSC, MSS, SSF, Sm, MMS and MDR, respectively. Then the quality of each plan with a certain set of parameters was evaluated by various evaluation indexe s. The differences of quality among different plans were analyzed by comparing t hese indexes. Results There was no influence on the quality of VMAT planning for the parameter MSC, MSS and SSF to be set with differen t values. However, the other three parameters, MSC, MSS and SSF, affecte d the quality of VMAT planning with different values. Along with the aggrandizem ent of Sm and MMS value, the dose distribution of VMAT plans gradually b ecame bad, while the number of control points, machine monitor units and irradia tion time were gradually reduced. And along with the aggrandizement of MDR v alue, the dose distribution of VMAT plans became bad gradually until a constant state was reached, and both the number of control points and machine monitor uni ts increased at first and then kept constant, while irradiation time decreased a t first and then kept constant. Conclusion The selections of pa rameter Sm, MMS and MDR impact the quality of VMAT planning greatly. It is very important to set the suitable value of Sm, MMS and MDR to get th e best planning quality for patients with different complexity.