Monaco计划系统通量平滑设定对宫颈癌调强放疗计划的影响

Impact of Fluence Smoothing Setting in Monaco Treatment Planning System on IMRT Plans for Cervical Cancer

【目的】探讨Monaco计划系统通量平滑设定对宫颈癌调强放疗计划的影响。【方法】40例宫颈癌患者,在相同优化条件下分别使用高(High)、中(Medium)、低(Low)、无(Off)四种通量平滑度进行设计及评估。比较四组计划的平均剂量(D mean)、最低剂量(D min)、适形度指数(CI)、均匀性指数(HI)、危及器官(OAR)受量及计划内子野数(Segment)、跳数(MU)、调制强度(MD)的差异。【结果】四组靶区的D min、D mean、CI、HI指标比较,差异均无统计学意义(P>0.05),同时OAR各项剂量学指标比较,差异无统计学意义(P>0.05)。机械参数方面,High组的MU及MD显著优于其余三组(P<0.05),四组在计划预估时间上比较,差异均无统计学意义(P>0.05)。【结论】四种通量平滑度下设计的计划均可达到临床应用需求,High平滑度,每射野最大控制点为30的参数用于宫颈癌术后同步加量放疗计划设计可提高计划效率。

【Objective】To compare the dosimetric differences in inverse intensity-modulated radiation therapy(IMRT)plans for postoperative concurrent dose escalation in cervical cancer using four different fluence smoothing parameters in the Monaco treatment planning system.【Methods】Forty cervical cancer patients were enrolled in the study.Treatment plans were designed and evaluated under the same optimization conditions using high(High),medium(Medium),low(Low),and no(Off)fluence smoothing parameters.The average dose(D mean),minimum dose(D min),conformity index(CI),homogeneity index(HI),organ at risk(OAR)doses,as well as mechanical parameters such as the number of segments,monitor units(MU),and modulation degree(MD)were compared among the four groups.【Results】No statistically significant differences were observed among the four groups regarding D min,D mean,CI,and HI for the target area(P>0.05).There were not any significant differences in OAR dosimetric parameters in the four groups(P>0.05).However,the High group showed significantly better MU and MD values compared to the other three groups(P<0.05).The estimated plan time showed no significant difference among the groups(P>0.05).【Conclusion】All plans designed with the four different fluence smoothing parameters meet the clinical requirements.The use of the High fluence smoothing parameter with a maximum of 30 control points per field in the design of IMRT plans for postoperative concurrent dose escalation in cervical cancer improves plan efficiency.