Experimental exploration of a mixed helium/carbon beam for online treatment monitoring in carbon ion beam therapy.
Experimental exploration of a mixed helium/carbon beam for online treatment monitoring in carbon ion beam therapy.
复制标题
混合氦/碳束在碳离子束治疗中在线治疗监测的实验探索。
DOI：
10.1088/1361-6560/ab6e52
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发表时间：
2020
影响因子：
3.5
通讯作者：
Volz L
中科院分区：
文献类型：
--
作者：
Volz L
最近，有人提出，混合氦/碳束可用于碳离子束治疗的在线监测。完全剥离后，两种离子物种表现出近似相同的质荷比，因此可能在同步加速器中同时加速到每个核子相同的能量。在相同的每核子能量下，氦离子的射程大约是碳离子的三倍，这可以允许同时使用碳离子束进行治疗和氦离子束进行成像。在这项工作中，测量和模拟的PMMA幻影，以及拟人幻影依次照射氦离子和碳离子束在相同的能量每核子。使用由平板CMOS传感器读出的薄塑料闪烁片制成的新型距离望远镜检测初级氦离子束和离开幻影的碳离子束的碎片尾部的范围。答10：1的碳与氦混合比，产生远高于碳碎片背景的氦信号，同时几乎不增加输送给患者的剂量。检测到PMMA体模中厚度为1 mm的窄空气间隙的范围调制，其影响笔形光束中不到四分之一的颗粒，证明了所提出的方法可实现的相对灵敏度。使用两个拟人的骨盆phanimetry它示出，小旋转的幻影，以及模拟肠气体运动引起可检测的变化，退出幻影的氦/碳束。讨论了氦/碳混合的未来前景和局限性及其技术可行性。
Recently, it has been proposed that a mixed helium/carbon beam could be used for online monitoring in carbon ion beam therapy. Fully stripped, the two ion species exhibit approximately the same mass/charge ratio and hence could potentially be accelerated simultaneously in a synchrotron to the same energy per nucleon. At the same energy per nucleon, helium ions have about three times the range of carbon ions, which could allow for simultaneous use of the carbon ion beam for treatment and the helium ion beam for imaging. In this work, measurements and simulations of PMMA phantoms as well as anthropomorphic phantoms irradiated sequentially with a helium ion and a carbon ion beam at equal energy per nucleon are presented. The range of the primary helium ion beam and the fragment tail of the carbon ion beam exiting the phantoms were detected using a novel range telescope made of thin plastic scintillator sheets read out by a flat-panel CMOS sensor. A 10: 1 carbon to helium mixing ratio is used, generating a helium signal well above the carbon fragment background while adding little to the dose delivered to the patient. The range modulation of a narrow air gap of 1 mm thickness in the PMMA phantom that affects less than a quarter of the particles in a pencil beam were detected, demonstrating the achievable relative sensitivity of the presented method. Using two anthropomorphic pelvis phantoms it is shown that small rotations of the phantom as well as simulated bowel gas movements cause detectable changes in the helium/carbon beam exiting the phantom. The future prospects and limitations of the helium/carbon mixing as well as its technical feasibility are discussed.