Carlino Antonio, Palmans Hugo, Gouldstone Clare, Trnkova Petra, Noerrevang Ole, Vestergaard Anne, Freixas Gloria Vilches, Bosmans Geert, Lorentini Stefano, Schwarz Marco, Koska Benjamin, Wulff Jörg, Vatnitsky Stanislav, Stock Markus
MedAustron Ion Therapy Center, Medical Physics, Wiener Neustadt, Austria.
MedAustron Ion Therapy Center, Medical Physics, Wiener Neustadt, Austria; National Physical Laboratory, Teddington, United Kingdom.
Z Med Phys. 2021 May;31(2):145-153. doi: 10.1016/j.zemedi.2021.01.003. Epub 2021 Mar 9.
An independent dosimetry audit based on end-to-end testing of the entire chain of radiation therapy delivery is highly recommended to ensure consistent treatments among proton therapy centers. This study presents an auditing methodology developed by the MedAustron Ion Beam Therapy Center (Austria) in collaboration with the National Physical Laboratory (UK) and audit results for five scanned proton beam therapy facilities in Europe.
The audit procedure used a homogeneous and an anthropomorphic head phantom. The phantoms were loaded either with an ionization chamber or with alanine pellets and radiochromic films. Homogeneously planned doses of 10Gy were delivered to a box-like target volume in the homogeneous phantom and to two clinical scenarios with increasing complexity in the head phantom.
For all tests the mean of the local differences of the absolute dose to water determined with the alanine pellets compared to the predicted dose from the treatment planning system installed at the audited institution was determined. The mean value taken over all tests performed was -0.1±1.0%. The measurements carried out with the ionization chamber were consistent with the dose determined by the alanine pellets with a mean deviation of -0.5±0.6%.
The developed dosimetry audit method was successfully applied at five proton centers including various "turn-key" Cyclotron solutions by IBA, Varian and Mevion. This independent audit with extension to other tumour sites and use of the correspondent anthropomorphic phantoms may be proposed as part of a credentialing procedure for future clinical trials in proton beam therapy.
强烈建议进行基于放射治疗全流程端到端测试的独立剂量学审核，以确保质子治疗中心之间治疗的一致性。本研究介绍了由奥地利MedAustron离子束治疗中心与英国国家物理实验室合作开发的一种审核方法，以及对欧洲五家扫描质子束治疗设施的审核结果。
审核程序使用了一个均匀体模和一个仿真人头模。体模中放置电离室或丙氨酸剂量计及放射变色胶片。在均匀体模中，向一个盒状靶区均匀计划照射10Gy剂量；在人头模中，向两个复杂度递增的临床场景照射。
对于所有测试，确定了用丙氨酸剂量计测定的水的绝对剂量与被审核机构安装的治疗计划系统预测剂量之间局部差异的平均值。所有测试的平均值为-0.1±1.0%。用电离室进行的测量与丙氨酸剂量计测定的剂量一致，平均偏差为-0.5±0.6%。
所开发的剂量学审核方法已成功应用于五个质子中心，这些中心采用了IBA、Varian和Mevion等公司的各种“交钥匙”回旋加速器解决方案。这种独立审核扩展到其他肿瘤部位并使用相应的仿真体模，可作为质子束治疗未来临床试验认证程序的一部分被推荐。
