Departamento de Física de Partículas, Universidad de Santiago, 15782-Santiago, Spain.
Phys Med Biol. 2010 Feb 21;55(4):1025-39. doi: 10.1088/0031-9155/55/4/008. Epub 2010 Jan 20.
This work focuses on neutron monitoring at clinical linac facilities during high-energy modality radiotherapy treatments. Active in-room measurement of neutron fluence is a complex problem due to the pulsed nature of the fluence and the presence of high photon background, and only passive methods have been considered reliable until now. In this paper we present a new active method to perform real-time measurement of neutron production around a medical linac. The device readout is being investigated as an estimate of patient neutron dose exposure on each radiotherapy session. The new instrument was developed based on neutron interaction effects in microelectronic memory devices, in particular using neutron-sensitive SRAM devices. This paper is devoted to the description of the instrument and measurement techniques, presenting the results obtained together with their comparison and discussion. Measurements were performed in several standard clinical linac facilities, showing high reliability, being insensitive to the photon fluence and EM pulse present inside the radiotherapy room, and having detector readout statistical relative uncertainties of about 2% on measurement of neutron fluence produced by 1000 monitor units irradiation runs.
这项工作专注于高能模式放射治疗期间临床直线加速器设施中的中子监测。由于通量的脉冲特性和存在高光子背景，对中子通量进行实时的室内主动测量是一个复杂的问题，到目前为止，只有被动方法被认为是可靠的。在本文中，我们提出了一种新的主动方法来实时测量医用直线加速器周围的中子产生。该设备的读数被认为是每次放射治疗期间患者中子剂量暴露的估计值。新仪器是基于微电子存储设备中的中子相互作用效应开发的，特别是使用了对中子敏感的 SRAM 设备。本文致力于仪器和测量技术的描述，展示了获得的结果，并对其进行了比较和讨论。在几个标准的临床直线加速器设施中进行了测量，结果表明该仪器具有高可靠性，对放射治疗室内存在的光子通量和电磁脉冲不敏感，并且在测量由 1000 个监测器单位照射运行产生的中子通量时，探测器读数的统计相对不确定度约为 2%。
