Novel tileable scintillator-based photon counting detector for clinical X-ray CT

用于临床 X 射线 CT 的新型可平铺闪烁体光子计数探测器

• 批准号: 8952025
• 负责人: Hamid Sabet
• 金额: $ 8.7万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8952025
• 关键词: Affect; Algorithms; Amplifiers; Applications Grants; Area; Attention; Behavior; CdZnTe; Cerium; Charge; Clinical; Consumption; Coupled; Data; Development; Diagnostic; Diagnostic Imaging; Diagnostic radiologic examination; Dose; Electric Capacitance; Electronics; Feasibility Studies; Future; Goals; Image; Individual; Lasers; Light; Lutetium; Mammography; Measures; Medical Imaging; Noise; Nuclear; Optics; Output; Patients; Performance; Photons; Physiologic pulse; Process; Property; Radiation; Research; Research Proposals; Resolution; Roentgen Rays; Semiconductors; Shapes; Side; Signal Transduction; System; Technology; Thick; Time; X-Ray Computed Tomography; base; clinical application; contrast imaging; cost; cost effective; density; design; detector; imaging system; improved; indexing; meetings; millimeter; novel; photon-counting detector; public health relevance; reconstruction; technology development

 DESCRIPTION (provided by applicant): Delivering high contrast diagnostic CT images while minimizing patient radiation dose has been the center of majority of all CT-related research. In this regard, improvement in the detector technology (alongside with automatic exposure control and improved reconstruction algorithms) may have the greatest impact. Current X- ray CT detectors operating in integration mode are not able to provide spectral information and also introduce large electronic noise in the acquired images. Current photon counting detectors (as alternative for integrating CT detectors) are based on direct conversion of the x-rays to electrica signal which relies on utilizing semiconductor materials (mainly Si, CdTe, CZT). For X-ray energies in medical imaging applications, Si becomes almost transparent resulting in a very low sensitivity and high patient dose. CdTe and CZT have been used for these energy ranges, however imposing technical challenges and performance issues such as charge sharing, pulse pileup and count rate capability, relatively low effective Z and low density compared with the current CT detector materials. Furthermore, limited availability of high purity materials (e.g. CZT can make a large area detector for clinical applications prohibitively expensive. While scintillation-based detectors are used in clinical nuclear imaging systems they cannot satisfy all the stringent requirements for clinical CT system at high flux mainly due to the lack of high light output scintillators with fast decay time as well as lack of reliable scintillator pixelation technologies to fabricate pixels smaller than 0.5x0.5 mm2. Our goal is to study the feasibility of a scintillator-based photon counting detector using pixelated high Z scintillator coupled with a dedicated ASIC where each ASIC pixel has a built-in photodiode, a charge sensitive preamplifier, a shaping amplifier with programmable peaking time, 3-4 energy windows and their associated counters. The significance of this research is that by using our scintillator pixelation technology, development of high-resolution photon counting CT detectors is achievable in a cost effective manner. The proposed detector will categorize the incident X-rays based on their energy and will handle the incident X-ray flux up to 108 photon/mm2/second as needed in clinical CT imaging.

 描述（由适用提供）：在最小化患者辐射剂量的同时，提供高对比度的诊断CT图像是所有与CT相关研究的大多数。在这方面，检测器技术的改进（以及自动暴露控制和改进的重建算法）可能会产生最大的影响。当前在集成模式下运行的X射线CT检测器无法提供光谱信息，并且在获得的图像中也引入了大型电子噪声。当前的光子计数检测器（作为集成CT检测器的替代方案）是基于X射线向电信号的直接转换，该信号依赖于使用半导体材料（主要是SI，CDTE，CZT）。对于医学成像应用中的X射线能量，SI几乎变得透明，导致敏感性非常低，患者剂量高。 CDTE和CZT已用于这些能量范围，但是与当前的CT检测器材料相比，施加了技术挑战和性能问题，例如电荷共享，脉搏堆积和计数速率能力，相对低有效Z和低密度。此外，高纯度材料的可用性有限（例如，CZT可以使昂贵的临床应用程序成为大面积检测器。尽管基于闪烁的检测器在临床核成像系统中使用了基于闪烁的检测器，但由于缺乏高光缺乏高光，它们无法满足所有严格的临床CT系统要求 具有快速衰减时间的输出闪烁体以及缺乏可靠的闪烁体像素化技术来制造小于0.5x0.5 mm2的像素。我们的目标是使用像素化的高Z闪烁体以及专用的ASIC研究基于闪烁体的光子计数检测器的可行性，其中每个ASIC像素都具有内置的光电二极管，充电敏感的前置放大器，形状的放大器以及可编程的峰值峰值时间，3-4-4个能量窗口，3-4-4个能量窗口和与之相关的对方。这项研究的意义是，通过使用我们的闪烁体像素化 技术，高分辨率光子计数CT检测器的开发以一种成本效益的方式成功。拟议的检测器将根据其能量对事件X射线进行分类，并根据需要在临床CT成像中根据需要处理入射X射线通量高达108个光子/mm2/秒。