Use of a two-dimensional ionization chamber array for proton therapy beam quality assurance
Use of a two-dimensional ionization chamber array for proton therapy beam quality assurance
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DOI：
10.1118/1.2963990
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发表时间：
2008-09-01
期刊：
影响因子：
3.8
通讯作者：
Gillin, Michael
中科院分区：
文献类型：
--
作者：
Arjomandy, Bijan;Sahoo, Narayan;Gillin, Michael
二维电离室阵列主要用于常规和调强放射治疗的质量保证。市场上还没有这种类型的商业设备可用于质子治疗的质量保证。我们研究了商用二维离子室阵列探测器Matrixx在质子治疗质量保证中的适用性。该设备设计用于光子和电子治疗的质量保证。该装置配备了32x32个平行板电离室，每个电离室的直径为4.5 mm，中心到中心的间距为7.62 mm。用250 MeV质子束对该装置测量的剂量进行了刻度。用160 MeV质子束测得堆积材料的水当量厚度为3.9 mm。用不同能量的质子束测量了剂量输出的重复性，并用Matrixx软件评价了测量的束流平坦度和对称性的一致性。将输出测量结果与使用0.6cc Farmer小室获得的临床调试射束数据进行比较。该协议一直被发现在1%的范围内。这些分布与薄膜剂量学以及水中的电离室数据进行了比较，具有很好的一致性。该装置被发现非常适合质子治疗束的质量保证。它实时提供快速的二维剂量分布信息，其精度可与电离室测量和胶片剂量测量相媲美。(C)2008年美国医学物理学家协会。
Two-dimensional ion chamber arrays are primarily used for conventional and intensity modulated radiotherapy quality assurance. There is no commercial device of such type available on the market that is offered for proton therapy quality assurance. We have investigated suitability of the MatriXX, a commercial two-dimensional ion chamber array detector for proton therapy QA. This device is designed to be used for photon and electron therapy QA. The device is equipped with 32x32 parallel plate ion chambers, each with 4.5 mm diam and 7.62 mm center-to-center separation. A 250 MeV proton beam was used to calibrate the dose measured by this device. The water equivalent thickness of the buildup material was determined to be 3.9 mm using a 160 MeV proton beam. Proton beams of different energies were used to measure the reproducibility of dose output and to evaluate the consistency in the beam flatness and symmetry measured by MatriXX. The output measurement results were compared with the clinical commissioning beam data that were obtained using a 0.6 cc Farmer chamber. The agreement was consistently found to be within 1%. The profiles were compared with film dosimetry and also with ion chamber data in water with an excellent agreement. The device is found to be well suited for quality assurance of proton therapy beams. It provides fast two-dimensional dose distribution information in real time with the accuracy comparable to that of ion chamber measurements and film dosimetry. (C) 2008 American Association of Physicists in Medicine.