Gated Optical DetectorsDose Guided Radiotherapy

一家小型电子样机公司已同意协助开发第二代探测器接口。由于光子计数模块的高压电路存在问题，该器件计划于2010年9月中旬交付。它将是一个具有4个检测通道的自门控系统，所有信号处理将完全通过硬件进行。此外，NRL正在开发新的光纤，这种光纤的剂量响应将更加均匀，并且将基于100微米的光纤，而不是目前的400微米模型。由此产生的系统将作为辐射剂量测定系统进行验证，并将用于非常规的临床和研究测量，包括小场和微场剂量测定，用于兆伏和千伏x射线和电子束。有两个可能的后续项目：(1)一个三期项目，开发用于剂量引导放射治疗的探测器阵列，或DGR。第一阶段是将纤维阵列发展成矩形或螺旋网格，并研究放射治疗期间产生的剂量图以及器官或光束定位的微小变化的影响。II期是了解相对于患者解剖位置的信号变化的含义，如果检测到的信号与参考值有预先确定的容限差异，则中断治疗。第三阶段是将网格信号的变化与辐射场的校正变化动态联系起来，实现对辐射治疗的在线、动态剂量控制。(2)另一项计划，发展以胶片为基础的光释光剂量计，以取代照相胶片进行剂量测量。使用磨碎的OSL玻璃分散在带有粘合剂的薄膜基板上进行初步测量是有希望的，但必须找到更好的方法来生产尺寸均匀的OSL颗粒。一种可能的方法是使用包含OSL分子链的纳米颗粒，我们目前正在与一家学术机构合作探索这种可能性。

A small electronics prototyping business has agreed to assist in the development of a second generation detector interface. Delivery of this device is scheduled for mid-September, 2010 due to problems with the high voltage circuits of the photon counting modules. It will be a self-gated system with 4 detection channels and all signal processing will be performed completely via hardware. Additionally, new fibers are being developed by NRL that will be more uniform in dose response and will be based on a 100 micron optical fiber rather than the current 400 micron model. The resulting system will undergo validation as a radiation dosimetry system and will be employed for non-routine clinical and research measurements involving small field and micro-field dosimetry for both megavoltage and kilovoltage x-ray and electron beams. There are 2 possible follow-on projects: (1) A three phase project to develop a detector array for dose-guided radiotherapy, or DGR. Phase I is to develop an array of fibers as either a rectangular or spiral grid and study the dose map generated during radiotherapy and the effect of small changes in organ or beam positioning. Phase II is to understand the meaning of signal change relative to the patient's anatomical position and to interrupt the treatment if detected signals differ from reference values by a predetermined tolerance margin. Phase III is to dynamically link the changes in grid signals to corrective changes in the radiation field for on-line, dynamic dose control of radiation treatments. (2) A separate project to develop a film-based OSL dosimeter as a replacement for photographic film for dosimetry measurements. Preliminary measurements using ground OSL glass dispersed on a film substrate with a binder were promising, but better methods must be found to produce OSL particles that are uniform in size. One possible approach is to employ nanoparticles incorporating OSL molecular chains, and we are currently partnering with an academic institution to explore this possibility.