【摘要】 目的通过制定设置不同计划参数的容积旋转调强(volumetric modulated arc therapy,VMAT)计划,并验证,研究各个参数对计划的影响。方法选取中国医科大学附属第一医院放疗科2014-01-06-04-03收治的10例直肠癌术后患者为研究对象,对10例患者计划分别设置不同参数,即机架角度间隔、准直器角度、叶片运动速度和最大出束时间,每例制定10个计划,相互对比、评估各参数变化对计划的影响。结果机架角度间隔(gantry spacing,GS)设置为GS=2°时计划时间为(264.7±27.3)s,治疗时间为(168.7±9.0)s;设置为GS=4°时的计划时间为(154.3±15.8)s,治疗时间为(157.6±8.8)s,两者比较差异均有统计学意义,t值分别为26.651和3.763,P值分别为<0.001和0.004。准直器角度设置为45°时的适型度指数(conformity index,CI)为0.922±0.01,均匀度指数(homogeneity index,HI)为0.062±0.011,验证结果的γ通过率为(95.82±1.98)%;准直器角度设置为0°时的CI为0.914±0.01,HI为0.073±0.011,验证结果的γ通过率为(94.56±2.55)%,两者比较差异均有统计学意义,t值分别为-4.000、3.498和2.733,P值分别为0.003、0.007和0.023。限定叶片速度为0.5cm/deg时的治疗时间为(127.4±13.9)s,叶片速度设置为Auto时的治疗时间(165.8±8.0)s,t=13.092,P<0.001;计划质量和QA结果没有明显改变,P>0.05。最大出束时间设置为120s时实际治疗时间为(220.6±13.1)s,最大出束时间设置为90s时实际治疗时间为(165.8±8.0)s,两者比较差异有统计学意义,t=-16.234,P<0.001。结论 VMAT计划各参数对计划的影响不同,在实际工作中根据实际需要进行适当的设置。更多还原

【Abstract】 OBJECTIVE To investigate the effect of the parameters of VMAT plan for the plan efficiency,quality and result of QA through making plans with different parameters and verifying these plans.METHODS Ten post-operated rectal cancer patients from The First Hospital of CMU during 2014-01-06-04-03,10 VMAT plans were generated for each patient basing on different parameter settings including gantry spacing(GS),collimator angle,leaf motion speed and maximum delivery time.Paired t test was adopted for the comparison of each plans to evaluate the influence of different parameters to treatment plan.RESULTS When setting gantry spacing GS=2°,planning time and treatment time were(264.7±27.3)s and(168.7±9.0)s,while setting GS=4°planning time was(154.3±15.8)s and treatment time was(157.6±8.8)s(t=26.651,P<0.001;t=3.763,P=0.004).When setting collimator angle as 45°,conformity index(CI)was 0.922±0.01,homogeneity index(HI)was 0.062±0.011,the result of verifying Gamma passing rates was(95.82±1.98)%.While setting collimator angle as 0°,the CI was 0.914±0.01,HI was 0.073±0.011,Gamma passing rate was(94.56±2.55)%,the difference was statistically significant(t=-4.000,P=0.003;t=3.498,P=0.007;t=2.733,P=0.023).Setting Limiting leaf motion speed as 0.5cm/deg,the treatment time was(127.4±13.9)s,setting Limiting leaf motion speed as auto,the treatment time was(165.8±8.0)s(t=13.092,P<0.001),showing no difference in planning quality and QA results(P>0.05).Setting Maximum delivery time as 120 s,the real treatment time was(220.6±13.1)s,setting maximum delivery time as 90 s,the real treatment time was(165.8±8.0)s,the difference was statistically significant(t=-16.234,P<0.001).CONCLUSIONS Different parameters affects planning results.Parameter settings should be adapted in practice.更多还原