目的通过两种调强放疗验证工具的分析比对，探讨一种全新三维验证工具临床应用的可行性。方法从接受调强放疗患者中随机抽取5例，分别在飞利浦Pinnacle 8．0D治疗计划系统中做MapCHECK Model 1175（Sun Nuclear，Melbourne，FL，USA）...目的通过两种调强放疗验证工具的分析比对，探讨一种全新三维验证工具临床应用的可行性。方法从接受调强放疗患者中随机抽取5例，分别在飞利浦Pinnacle 8．0D治疗计划系统中做MapCHECK Model 1175（Sun Nuclear，Melbourne，FL，USA）设计和Delta4（ScandiDos，Sweden）设计，然后分别在瓦里安Clinal23EX直线加速器上做剂量验证测量。计较Delta4和MapCHECK计划中相同剂量偏差（DD2％、DD3％、DD4％）和吻合距离（DTA2mm、DTA3rnm、DTA4mm）数值时的通过率差异。结果用MapCHECK Model 1175测量的剂量偏差为DD2％DTA2mm、DD3％DTA3mm、DD4％DTA4mm时总的平均通过率分别为84．7％、97．1％、99．3％；用Delta4测量的分别为86．2％、98．2％、99．6％；3组数据比较差异均有统计学意义（t=3．94，P=0．003；t=3．17，P=0．011；t=3．05，P=0．014）。MapCHECK的质量保证计划中把每个射野的大机架角度都要改为0°，而Deha4无任何改变。在测量过程中重力对多叶光栅叶片到到位精度影响、治疗床对剂量分布影响、地磁对剂量系统影响在Delta4测量中都可得到体现。结论Deha4是调强放疗非常理想的验证工具。展开更多
Background and Objective:The planning dose distribution of intensity-modulated radiation therapy(IMRT) has to be verified before clinical implementation.The commonly used verification method is to measure the beam flu...Background and Objective:The planning dose distribution of intensity-modulated radiation therapy(IMRT) has to be verified before clinical implementation.The commonly used verification method is to measure the beam fluency at 0 degree(0°) gantry angle with a 2-dimensional(2D) detector array,but not the composite dose distribution of the real delivery in the planned gantry angles.This study was to investigate the angular dependence of a 2D diode array(2D array) and the feasibility of using it to verify the composite dose distribution of IMRT.Methods:Angular response of the central detector in the 2D array was measured for 6 MV X-ray,10 cm × 10 cm field and 100 cm source axis distance(SAD) in different depths.With the beam incidence angle of 0°-60°,at intervals of 10°,and inherent buildup of the 2D array(2 g/cm2),the array was irradiated and the readings of the central diode were compared with the measurement of thimble ionization chamber.Using a combined 30 cm × 30 cm × 30 cm phantom which consisted of solid water slabs on top and underlying the 2D array,with the diode detectors placed at 8 g/cm2 depth,measurements were taken for beam angles of 0°-180° at intervals of 10° and compared with the calculation of treatment planning system(TPS) that pre-verified with ion chamber measuring.Results:Differences between the array detector and thimble chamber measurements were greater than 1% and 3.5% when the beam angle was larger than 30° and 60°,respectively.The measurements in the combined phantom were different from the calculation as high as 20% for 90° beam angle,2% at 90°± 5° and less than 1% for all the other beam angles.Conclusions:The 2D diode array is capable of being used in composite dose verification of IMRT when the beam angles of 90°± 5° and 270°± 5° are avoided.展开更多
文摘目的通过两种调强放疗验证工具的分析比对，探讨一种全新三维验证工具临床应用的可行性。方法从接受调强放疗患者中随机抽取5例，分别在飞利浦Pinnacle 8．0D治疗计划系统中做MapCHECK Model 1175（Sun Nuclear，Melbourne，FL，USA）设计和Delta4（ScandiDos，Sweden）设计，然后分别在瓦里安Clinal23EX直线加速器上做剂量验证测量。计较Delta4和MapCHECK计划中相同剂量偏差（DD2％、DD3％、DD4％）和吻合距离（DTA2mm、DTA3rnm、DTA4mm）数值时的通过率差异。结果用MapCHECK Model 1175测量的剂量偏差为DD2％DTA2mm、DD3％DTA3mm、DD4％DTA4mm时总的平均通过率分别为84．7％、97．1％、99．3％；用Delta4测量的分别为86．2％、98．2％、99．6％；3组数据比较差异均有统计学意义（t=3．94，P=0．003；t=3．17，P=0．011；t=3．05，P=0．014）。MapCHECK的质量保证计划中把每个射野的大机架角度都要改为0°，而Deha4无任何改变。在测量过程中重力对多叶光栅叶片到到位精度影响、治疗床对剂量分布影响、地磁对剂量系统影响在Delta4测量中都可得到体现。结论Deha4是调强放疗非常理想的验证工具。
基金Wu Jie-ping Medical Foundation (No. WKJ2005-3-006-7)
文摘Background and Objective:The planning dose distribution of intensity-modulated radiation therapy(IMRT) has to be verified before clinical implementation.The commonly used verification method is to measure the beam fluency at 0 degree(0°) gantry angle with a 2-dimensional(2D) detector array,but not the composite dose distribution of the real delivery in the planned gantry angles.This study was to investigate the angular dependence of a 2D diode array(2D array) and the feasibility of using it to verify the composite dose distribution of IMRT.Methods:Angular response of the central detector in the 2D array was measured for 6 MV X-ray,10 cm × 10 cm field and 100 cm source axis distance(SAD) in different depths.With the beam incidence angle of 0°-60°,at intervals of 10°,and inherent buildup of the 2D array(2 g/cm2),the array was irradiated and the readings of the central diode were compared with the measurement of thimble ionization chamber.Using a combined 30 cm × 30 cm × 30 cm phantom which consisted of solid water slabs on top and underlying the 2D array,with the diode detectors placed at 8 g/cm2 depth,measurements were taken for beam angles of 0°-180° at intervals of 10° and compared with the calculation of treatment planning system(TPS) that pre-verified with ion chamber measuring.Results:Differences between the array detector and thimble chamber measurements were greater than 1% and 3.5% when the beam angle was larger than 30° and 60°,respectively.The measurements in the combined phantom were different from the calculation as high as 20% for 90° beam angle,2% at 90°± 5° and less than 1% for all the other beam angles.Conclusions:The 2D diode array is capable of being used in composite dose verification of IMRT when the beam angles of 90°± 5° and 270°± 5° are avoided.
