STORAGE PHOSPHOR FILM FOR RADIATION THERAPY DOSIMETRY

现代放射治疗模式，例如，调强放射治疗（IMRT）， 其具有具有陡峭梯度的高度共形剂量分布。启用这些模式需要 使用正在紧张研究和开发的多维剂量计。最近的一份报告 来自放射物理中心（RPC）的数据显示，大约30%的机构未能提供剂量， 分配到与其自身治疗计划一致的头颈部体模，误差在7%或4 mm内。 RPC报告提供了强有力的证据，证明IMRT实施容易出错，并提高了质量 需要保证工具。本研究的首要假设是低Z KCl：Eu 2+存储 荧光膜（SPF）将提供第一个能够进行基准剂量测定的二维剂量计 测量，大大改善放射治疗的调试和质量保证 治疗计划和实施系统。本论文的第一个目标是优化KCl：Eu ~（2+）存储荧光粉颗粒 组合物和化学结构，以最大化辐射灵敏度、辐射硬度、响应均匀性， 信号稳定性。我们的第二个目标是开发一种工艺，通过蒸发优化的 在AIM 1中使用物理气相沉积将存储磷光体开发到大约1微米的厚度 在几乎与水相当的基质上。我们的第三个目标是证明， 目标2将提供基准质量的剂量分布测量，并展示 通过构建平面和圆柱形剂量计的SPF制造过程。

Modern radiation therapy modalities, for example, intensity modulated radiation therapy (IMRT), are associated with highly conformal dose distributions with steep gradients. Commissioning of these modalities requires the use of multidimensional dosimeters which have been under intense research and development. A recent report from the Radiological Physics Center (RPC) revealed that roughly 30% of institutions failed to deliver a dose distribution to a head-and-neck phantom that agrees with their own treatment plan to within 7% or 4 mm. The RPC report provides strong evidence that IMRT implementation is prone to error and that improved quality assurance tools are required. The overarching hypothesis of this research is that a low-Z KCl:Eu2+ storage phosphor film (SPF) will provide the first 2D dosimeter capable of conducting benchmark dosimetry measurements, substantially improving the commissioning and quality assurance of radiation therapy treatment planning and delivery systems. Our first aim is to optimize KCl:Eu2+ storage phosphor particle composition and chemical structure to maximize radiation sensitivity, radiation hardness, response uniformity, and signal stability. Our second aim is to develop a process to fabricate an SPF by evaporating the optimized storage phosphor developed in aim 1 to a thickness on the order of one micron using physical vapor deposition onto a nearly water-equivalent substrate. Our third aim is to demonstrate that the SPF dosimeter developed in aim 2 will provide benchmark-quality dose distribution measurements and to demonstrate the flexibility of the SPF fabrication process by building planar and cylindrical dosimeters.