Influence of secondary neutrons induced by proton radiotherapy for cancer patients with implantable cardioverter defibrillators.
Influence of secondary neutrons induced by proton radiotherapy for cancer patients with implantable cardioverter defibrillators.
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DOI：
10.1186/1748-717x-7-10
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发表时间：
2012-01-29
期刊：
影响因子：
--
通讯作者：
Sakurai H
中科院分区：
文献类型：
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作者：
Hashimoto T;Isobe T;Hashii H;Kumada H;Tada H;Okumura T;Tsuboi K;Sakae T;Aonuma K;Sakurai H
虽然质子放射治疗是一种很有前途的新方法，癌症患者，功能干扰是一个问题，植入心脏复律除颤器（ICD）的患者。本研究的目的是阐明质子放射治疗产生的次级中子对ICD的影响。实验装置模拟植入ICD患者的质子放射治疗。四个新的ICD被放置在0.3厘米的横向和3厘米远侧外的辐射领域，以评估二次中子的影响。在10次照射中，累积的野内辐射剂量为107戈伊，剂量率为2戈伊/min，野大小为10 × 10 cm 2。在每次辐射分次后，由ICD程控仪分析治疗对ICD的干扰。用蒙特-卡罗模拟方法估算了次级中子的剂量分布。上电复位的频率（程控起搏模式暂时变为安全备份模式时的最严重软错误）为1/约50戈伊。所有器械中记录的软错误总数为29个，发生率约为每15戈伊1个软错误。未检测到永久性器械故障。体模中每1戈伊质子剂量的次级中子的计算剂量约为1.3-8.9 mSv/戈伊。在本实验设置下，概率约为每50戈伊1次上电复位，低于质子放射治疗中通常使用的剂量水平（60-80戈伊）。需要在各种情况下进行进一步的定量分析，以建立关于植入ICD的癌症患者质子放射治疗的指南。
Although proton radiotherapy is a promising new approach for cancer patients, functional interference is a concern for patients with implantable cardioverter defibrillators (ICDs). The purpose of this study was to clarify the influence of secondary neutrons induced by proton radiotherapy on ICDs. The experimental set-up simulated proton radiotherapy for a patient with an ICD. Four new ICDs were placed 0.3 cm laterally and 3 cm distally outside the radiation field in order to evaluate the influence of secondary neutrons. The cumulative in-field radiation dose was 107 Gy over 10 sessions of irradiation with a dose rate of 2 Gy/min and a field size of 10 × 10 cm2. After each radiation fraction, interference with the ICD by the therapy was analyzed by an ICD programmer. The dose distributions of secondary neutrons were estimated by Monte-Carlo simulation. The frequency of the power-on reset, the most serious soft error where the programmed pacing mode changes temporarily to a safety back-up mode, was 1 per approximately 50 Gy. The total number of soft errors logged in all devices was 29, which was a rate of 1 soft error per approximately 15 Gy. No permanent device malfunctions were detected. The calculated dose of secondary neutrons per 1 Gy proton dose in the phantom was approximately 1.3-8.9 mSv/Gy. With the present experimental settings, the probability was approximately 1 power-on reset per 50 Gy, which was below the dose level (60-80 Gy) generally used in proton radiotherapy. Further quantitative analysis in various settings is needed to establish guidelines regarding proton radiotherapy for cancer patients with ICDs.