目的 分析2 010例调强放疗计划剂量验证结果,为改进和完善调强放疗计划验证方法提供参考。方法 回顾性分析北京大学第三医院2012年2月—2016年2月美国瓦里安公司Trilogy加速器治疗的2 010例计划的剂量验证结果,其中调强放射治疗(IMRT)计划965例,容积旋转调强放疗(VMAT)计划1 045例。计划设计使用Eclipse计划系统,剂量验证采用MatriXX及Multicube模体。分析计划和测量等中心点剂量差异,3%/3 mm标准平面剂量分布的γ通过率。等中心点剂量差异〈±3%定为通过,平面剂量分布γ通过率〉90%定为通过。分析病变部位、治疗技术(IMRT和VMAT)对计划验证通过率的影响。结果 2 010例计划等中心点剂量平均差异为-0.3%±2.4%,γ通过率为97.9%±3.4%。88.2%和96.7%的计划能够通过点剂量验证和平面剂量验证标准。不同病变部位计划验证γ通过率不同(F=3.09,P〈0.05)。不同病变计划点剂量和面剂量验证通过率不同(χ2=40.93、39.15,P〈0.05)。IMRT和VMAT计划验证点剂量通过率和面剂量验证通过率差异均无统计学意义(P〉0.05)。结论 大部分调强放疗计划能够通过计划验证,不同病变部位计划验证通过率不同,IMRT和VMAT计划验证通过率无差异。
Objective To analyze the patient-specific dosimetric verification results of 2 010 intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) plans from different treatment sites, and provide a reference for improving the patient-specific dosimetric verification program.Methods A total of 2 010 (965 IMRT and 1 045 VMAT) patient-specific dosimetric verification results were reviewed for isocenter dose difference and percentage of pixels passing planar dose γ analysis. All plans were designed with Eclipse planning system and delivered with Trilogy linear accelerator from February 2012 to February 2016. The dosimetric verification was performed with MatriXX array together with Multicube phantom. Point dose difference larger than ±3% and/or γ pass rate (3%/3 mm) less than 90% was defined as plan failure. Additional analysis was conducted for trends in difference of pass rates with treatment site and delivery technique (IMRT vs. VMAT). Results The mean isocenter difference between measured and calculated doses was -0.3%±2.4% for 2 010 plans. The mean percentage of pixels passing the γ criteria was 97.9%±3.4%. 88.2% and 96.7% of plans passed the point and planar dose verification, respectively. The γ pass rate was different among the treatment sites (F=3.09, P〈0.05). The pass rate of point and planar dose difference was different among the treatment sites(χ2=40.93, 39.15, P〈0.05). There was no difference between IMRT and VMAT plans for both point dose and planar dose evaluation (P〉0.05). Conclusions Most of IMRT and VMAT plans passed the tolerance criteria of ±3% and 90% for point and planar dose verification with MatriXX together with Multicube phantom, respectively. Both point and planar dose verification results varied among treatment sites, whereas no significant difference was found between IMRT and VMAT.