Radio‐fluorogenic nanoclay gel dosimeters with reduced linear energy transfer dependence for carbon‐ion beam radiotherapy
Radio‐fluorogenic nanoclay gel dosimeters with reduced linear energy transfer dependence for carbon‐ion beam radiotherapy
复制标题
减少碳离子束放射治疗线性能量转移依赖性的放射性荧光纳米粘土凝胶剂量计
DOI：
10.1002/mp.16092
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发表时间：
2022
期刊：
影响因子：
3.8
通讯作者：
Fukuda Shigekazu
中科院分区：
文献类型：
--
作者：
Maeyama Takuya;Mochizuki Anri;Yoshida Kazuki;Fukunishi Nobuhisa;Ishikawa Kenichi L.;Fukuda Shigekazu
目的高线性能量传递（LET）辐射的剂量分布的精确评估仍然是一个挑战，因为大多数剂量计的信号将由于高电离密度而饱和。这种测量对于重离子束癌症治疗尤其重要。在此基础上，本文研究了基于辐射诱导化学反应的三维凝胶剂量学的高LET效应。本研究的目的是创建一种离子束放射性荧光凝胶剂量计，降低了LET的影响。方法制备纳米粘土放射性荧光凝胶（NC - RFG）剂量计，通常含有100 μM二氢霍达明123 （DHR123）和2.0 wt%纳米粘土，并添加促进Fenton或类Fenton反应的催化添加剂。采用荧光凝胶扫描仪研究了不同组成的NC - RFG剂量计在碳离子束下的放射学特性。结果制备的NC - RFG剂量计能够产生反映碳离子束剂量谱的荧光强度分布。结果表明，降低不利的LET依赖性是由于DHR123和H2O2（一种分子辐射分解产物）之间的反应加速。研究了不同制备条件对凝胶放射学性能的影响。确定了最佳的h2o2催化剂为1 mM Fe3+离子，添加100 mM吡啶也可以提高灵敏度。该技术允许首次评估碳离子束在几Gy的典型治疗水平下的深度剂量谱，而不会产生LET效应。
PurposeThe precise assessment of the dose distribution of high linear energy transfer (LET) radiation remains a challenge, because the signal of most dosimeters will be saturated due to the high ionization density. Such measurements are particularly important for heavy‐ion beam cancer therapy. On this basis, the present work examined the high LET effect associated with three‐dimensional gel dosimetry based on radiation‐induced chemical reactions. The purpose of this study was to create an ion beam radio‐fluorogenic gel dosimeter with a reduced effect of LET.MethodsNanoclay radio‐fluorogenic gel (NC‐RFG) dosimeters were prepared, typically containing 100 μM dihydrorhodamine 123 (DHR123) and 2.0 wt% nanoclay together with catalytic additives promoting Fenton or Fenton‐like reactions. The radiological properties of NC‐RFG dosimeters having different compositions in response to a carbon‐ion beam were investigated using a fluorescence gel scanner.ResultsAn NC‐RFG dosimeter capable of generating a fluorescence intensity distribution reflecting the carbon‐ion beam dose profile was obtained. It was clarified that the reduction of the unfavorable LET dependence results from an acceleration of the reactions between DHR123 and H2O2, which is a molecular radiolysis product. The effects of varying the preparation conditions on the radiological properties of these gels were also examined. The optimum H2O2catalyst was determined to include 1 mM Fe3+ions, and the addition of 100 mM pyridine was also found to increase the sensitivity.ConclusionsThis technique allows the first‐ever evaluation of the depth–dose profile of a carbon‐ion beam at typical therapeutic levels of several Gy without LET effect.