Comparison of multi-institutional Varian ProBeam pencil beam scanning proton beam commissioning data
Comparison of multi-institutional Varian ProBeam pencil beam scanning proton beam commissioning data
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DOI：
10.1002/acm2.12078
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发表时间：
2017-05-01
影响因子：
2.1
通讯作者：
Langen, Katja
中科院分区：
文献类型：
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作者：
Langner, Ulrich W.;Eley, John G.;Langen, Katja
目的：质子点扫描射束的调试射束数据进行了比较的前两个瓦里安ProBeam网站在美国，在马里兰州质子治疗中心（MPTC）和斯克里普斯质子治疗中心（SPTC）。此外，在何种程度上可以匹配的机架房间之间的光束在MPTC.Method：光束数据为两个网站获得独立的剂量测定系统和比较。积分深度剂量曲线（IDDs），获得与布拉格峰离子室在一个3D水槽笔形束在这两个网站。在距等中心不同距离处，以0度机架角度以及机架角度的函数采集光斑轮廓。比较了SPTC和MPTC机架之间的绝对剂量校准。剂量验证的测试计划，输出作为机架角度的函数，监视器单元（MU）的线性，端效应，剂量率的依赖性，和计划的再现性进行了比较，为不同的机架在MPTC.Results：IDDs为两个网站是相似的，除了在高原地区，SPTC数据平均高4.5%，较低的能量。随着能量的增加，在平台区的这种增加减少，能量高于180 MeV没有显着差异。在水中的范围一致的所有能量在0.5 mm内。在空气中的斑点轮廓的sigmas在10%的协议在等中心。该差异随着探测器与等中心点的距离增加而增加。在两个地点测量的机架绝对剂量一致性在1%以内。测试计划、输出（作为机架角度的函数）、MU线性、末端效应、剂量率依赖性和计划再现性均在TG 142给出的公差范围内。结论：两个站点和不同机架室之间的射束数据匹配良好。
Purpose: Commissioning beam data for proton spot scanning beams are compared for the first two Varian ProBeam sites in the United States, at the Maryland Proton Treatment Center (MPTC) and Scripps Proton Therapy Center (SPTC). In addition, the extent to which beams can be matched between gantry rooms at MPTC is investigated.Method: Beam data for the two sites were acquired with independent dosimetry systems and compared. Integrated depth dose curves (IDDs) were acquired with Bragg peak ion chambers in a 3D water tank for pencil beams at both sites. Spot profiles were acquired at different distances from the isocenter at a gantry angle of 0 degrees as well as a function of gantry angles. Absolute dose calibration was compared between SPTC and the gantries at MPTC. Dosimetric verification of test plans, output as a function of gantry angle, monitor unit (MU) linearity, end effects, dose rate dependence, and plan reproducibility were compared for different gantries at MPTC.Results: The IDDs for the two sites were similar, except in the plateau region, where the SPTC data were on average 4.5% higher for lower energies. This increase in the plateau region decreased as energy increased, with no marked difference for energies higher than 180 MeV. Range in water coincided for all energies within 0.5 mm. The sigmas of the spot profiles in air were within 10% agreement at isocenter. This difference increased as detector distance from the isocenter increased. Absolute doses for the gantries measured at both sites were within 1% agreement. Test plans, output as function of gantry angle, MU linearity, end effects, dose rate dependence, and plan reproducibility were all within tolerances given by TG142.Conclusion: Beam data for the two sites and between different gantry rooms were well matched.