Gated Optical DetectorsDose Guided Radiotherapy

现有原型探测器系统的所有体模研究已经完成。该系统还被成功地用于测量新获得的具有很小孔径的立体定向敷贴器的输出因子。用蒙特卡罗计算和辐射变色薄膜对测量结果进行了验证。在商业原型生产出来之前，这个项目已经完成了。为这项任务选择的原始公司无法在分配的时间范围内完成这一单位，并违约了其协议条款。NRL正在选择一家新的公司，但在完成这一过程之前，新公司可以生产出一个可行的装置，这个项目不能进一步进展。一旦发生这种情况，还有另外两个后续项目：(1)开发用于剂量引导放射治疗的探测器阵列的三阶段项目，即DGR。第一阶段是将纤维阵列发展为矩形或螺旋网格，并研究放射治疗期间产生的剂量图以及器官或射束位置的微小变化的影响。第二阶段是了解相对于患者解剖位置的信号变化的意义，如果检测到的信号与参考值相差预定的容差，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地联系起来，以便在线、动态地控制放射治疗的剂量。(2)开发胶片OSL剂量计，以取代照相胶片进行剂量测量的另一个项目。使用研磨的OSL玻璃分散在带有粘结剂的薄膜衬底上的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纳米颗粒填充OSL分子链，我们目前正在与一家学术机构合作探索这种可能性。

All phantom studies with the existing prototype detector system have been completed. The system was also used successfully to measure the output factor of newly acquired stereotactic applicators with very small apertures. The measurements were validated with Monte Carlo calculations as well as with radiochromic film. This project has reached its until a commercial prototype is produced. The original company selected for this task was unable to complete such a unit in the allotted time frame and has defaulted on the terms of its agreement. NRL is in the process of selecting a new company, but until this is done and the new company can produce a workable unit, this project cannot progress further. Once this happens, there are 2 additional 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 incorpoprating OSL molecular chains, and we are currently partnering with an academic institution to explore this possibility.