LASER BASED MONOENERGETIC AND TUNABLE X RAY SYSTEM

描述（改编自申请人的摘要）： 管的特点是低输出，低亮度，大焦斑， 多色光子能量分布。 大焦点问题是 尤其是在放大工作中存在问题。 低产出要求 不希望长时间曝光。 多色光谱分布， 具有非常有限的平均光子能量控制，阻碍了有效应用 使德萨不切实际。 申请人提出了一种新的X光片 通过将高能激光脉冲聚焦在表面上而产生的源 固体。 这种基于激光的光源非常明亮， 来自非常小的焦点区域的非常短的脉冲（低于1 μ s）的形式 (as低至10 μ m）。 临床系统的估计成本与 旋转的阳极单元。 这个新的优点是 基于激光的源依赖于它具有一次性目标的事实，该一次性目标 在每个激光脉冲之后被替换。 目标的元素组成 因此在随后的激光脉冲之间快速地（数十Hz）改变。 这 允许定制（包括优化的K边缘滤波器）光谱 特征发射线的位置到特定成像tast（例如， 放大研究中的患者厚度或造影剂的K边缘 在DSA研究中）。 由于基于激光的X射线的高亮度 源，一个球形弯曲晶体单色器可以插入之间的 允许利用近单能X射线， 真正的数字能量减影血管造影研究。 多色 由电子碰撞管产生的X射线束的结构不 允许与感兴趣对象的K边缘精确匹配，并且始终 与典型的X射线探测器的最佳能量响应不匹配 用于放射学。 因此，可以预期， 近单能X射线源将导致降低积分剂量， 根据受试者的成分精确调整X射线能量， 并且通过使X射线能量与优化的 检测器 在这个拟议的项目中，申请人提出研究， 开发，评估和优化基于激光的超微聚焦， 用于放大的基于短脉冲激光的X射线源 DSA研究和单色X射线系统LAMOX（基于激光的单色 X射线）用于数字能量减影血管造影术（德萨）。 该项目将与X射线之间的密切合作实现 物理学家（单色仪），激光物理学家（激光x射线源），医疗 物理学家、生理学家和放射科医生（评估和优化 通过幻影研究的系统）。 该项目的具体目标是 优化图像质量和剂量利用，并证明 基于激光的X射线系统作为可行的临床， 以医院为基础，替代传统的放大、DSA和德萨 系统.

DESCRIPTION (Adapted from Applicant's Abstract): The conventional x-ray tube is characterized by low output, low brightness, a large focal spot and a polychromatic photon energy distribution. The large focal spot problem is especially problematic in magnification work. The low output mandates undersirable long exposure times. The polychromatic spectral distribution, with very limited mean photon energy control, impedes effective application of DSA and makes DESA impractical. The applicants proposed a new x-ray source that is created by focusing a high energy laser pulse on the surface of solids. This laser-based source is very bright and delivers radiation in the form of very short pulses (below 1 us) from a very small focal spot area (as low as 10 um). The estimated cost of a clinical system is comparable to the rotating anode-based units. An additional advantage of this new laser-based source rests on the fact that it has a disposable target which is replaced after each laser pulse. The target's elemental composition can be thus rapidly (tens of Hz) changed between subsequent laser pulses. This allows tailoring (including optimized K-edge filters) of the spectral position of characteristic emission lines to the specific imaging tast (e.g. patient thickness in magnification studies or the K-edge of a contrast agent in DSA studies). Due to the high brightness of the laser-based x-ray source, a spherically bent crystal monochromator can be inserted between the target and the patient allowing utilization of near-monoenergetic x-rays for true digital energy subtraction angiography studies. The polychromatic structure of the x-ray beam generated by an electron-impact tube does not allow precise matching to the K-edge of the object of interest and is always mismatched with the optimal energy response of the typical x-ray detectors used in radiology. Therefore, one could expect that the application of the near-monoenergetic x-ray source will result in lowering the integral dose by precisely tuning the x-ray energy according to the subject's composition and thickness and by better matching the x-ray energy with the optimized detector. In this proposed project, the applicants proposed to study, develop, evaluate, and optimize a laser-based ultra-microfocused and very short pulsed laser-based x-ray source for application in magnification and DSA studies and monochromatic x-ray system LAMOX (LAser-based Monochromatic X-rays) for application in digital energy subtraction angiography (DESA). This project will be realized with close collaboration among x-ray physicists (monochromator), laser physicists (laser x-ray source), medical physicists, a physiologist and radiologists (evaluation and optimization of the system through phantom studies). The specific goals of this project are to optimize image quality and dose utilization and to demonstrate the economic feasibility of the laser-based x-ray systems as a viable clinical, hospital based, alternative to traditional magnification, DSA and DESA systems.