Reduced Afterglow Scintillator Films for High Speed Medical Imaging

用于高速医学成像的减少余辉闪烁体薄膜

• 批准号: 7932004
• 负责人: VIVEK V NAGARKAR
• 金额: $ 68.69万
• 依托单位: RADIATION MONITORING DEVICES, INC.
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-18 至 2012-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7932004
• 关键词: Affect; Area; Arts; Ceramics; Characteristics; Charge; Chemicals; Communities; Complement; Complex; Cost Savings; Data; Deposition; Development; Devices; Diagnostic; Digital Mammography; Dimensions; Discipline of Nuclear Medicine; Dose; Due Process; Dura Mater; Elements; Equipment; Error Sources; Evaluation; Exhibits; Exposure to; Film; Fluoroscopy; Gamma Rays; Goals; Hand; Image; Kinetics; Life; Light; Medical; Medical Imaging; Modality; Morphology; Nature; Nuclear; Operative Surgical Procedures; Output; Patients; Performance; Phase; Photons; Physics; Physiologic pulse; Positron-Emission Tomography; Process; Property; Radiation; Radionuclide Imaging; Research Personnel; Residual state; Resolution; Sampling; Scanning; Security; Shadowing (Histology); Silicon; Source; Spectrum Analysis; Speed; Structure; System; Techniques; Technology; Temperature; Thick; Thoracic Radiography; Time; Variant; Vendor; X-Ray Computed Tomography; X-Ray Computed Tomography Scanners; attenuation; base; commercial application; commercialization; cone-beam computed tomography; cooperative study; cost; data acquisition; density; detector; economic impact; evaporation; imaging modality; improved; interest; irradiation; melting; operation; programs; public health relevance; sensor; single photon emission computed tomography; tomography

DESCRIPTION (provided by applicant): While many exotic new scintillation materials are now being developed, few even come close to CsI:Tl in performance and versatility. Widely available commercially at low cost, CsI:Tl not only has superb scintillation efficiency, but also can readily be fabricated as large-area microcolumnar films for high-resolution imaging, making it the material of choice for a wide range of applications. Unfortunately, CsI:Tl exhibits both a strong afterglow component in its scintillation decay and severe hysteresis after prolonged irradiation, limiting achiev- able energy resolution and imaging quality and speed. These shortcomings effectively preclude its use in applica- tions such as radionuclide imaging and medical CT, where its low cost could otherwise have immense economic impact. An improved form of CsI:Tl scintillator can reduce the cost of critical life-saving medical equipment such as X-ray CT scanners, fluoroscopy systems and other devices that rely on rapid data acquisition. In systematic studies of the cooperative effects of codopants in CsI:Tl, we have identified additives that can suppress its afterglow by as much as two orders of magnitude while maintaining its extraordinary scintillation properties. We also find that similar treatment can diminish hysteresis by more than a factor of ten, represent- ing a major breakthrough that has eluded researchers for decades. Moreover, we have clearly established that, through a co-evaporation technique, we can deposit thick microcolumnar films of this modified material, which provide very high spatial resolution appropriate for such new and exciting applications as "nanoSPECT" and high-speed cone-beam CT using flat panel detectors. With these exceptional properties, codoped CsI:Tl is now poised for exploitation in many rapid imaging modalities from which CsI:Tl had been previously excluded. But while we have achieved all these desirable effects in melt-grown crystals, we have not yet combined them at satisfactory levels at a single film composition; this is the specific goal of Phase I. Having already established the feasibility of the multicomponent deposition process itself, we will reach this goal through careful and system- atic variation of deposition parameters such as source and substrate temperatures, source-substrate distances, and chemical make-up of the sources themselves. Phase I will produce material with scintillation properties at least as good as in melt-grown single crystals, thereby becoming immediately useful for commercial evaluation. Phase II has far more comprehensive goals than Phase I. Here we will seek to optimize the material in terms of both chemical composition and physical morphology. In addition, guided by the results of Phase I and input from substantial new theoretical support, we will seek to understand both the mechanisms responsible for the observed effects and the kinetic factors that govern the deposition process itself. Cognizant of their ultimate applications, we will grow microcolumnar films of various dimensions ranging from 5 x 5 cm2 to 50 x 50 cm2, and demonstrate their utility by evaluating film performance in CBCT and SPECT modes of operation. Finally, we will promote commercialization through cooperative programs with potential users of this technology. PUBLIC HEALTH RELEVANCE: The widely available, low cost CsI:Tl not only has superb scintillation efficiency, but also can readily be fabricated as large-area microcolumnar films for high-resolution imaging, making it the material of choice for a wide range of applications. Unfortunately, CsI:Tl exhibits both a strong afterglow component in its scintillation decay and severe hysteresis after prolonged irradiation, limiting achievable energy resolution and imaging quality and speed. These shortcomings effectively preclude its use in applications such as radionuclide imaging and medical CT, where its low cost could otherwise have immense economic impact. An improved form of CsI:Tl scintillator, such as the one proposed here, can reduce the cost of critical life-saving medical equipment such as X-ray CT scanners, fluoroscopy systems and other devices that rely on rapid data acquisition.

描述（由申请人提供）：虽然现在开发了许多异国情调的新闪烁材料，但很少有人在性能和多功能性方面接近CSI：TL。 CSI：TL不仅具有出色的闪烁效率，而且可以轻松地作为大面积微型彩色膜进行高分辨率成像，使其成为广泛应用的首选材料。不幸的是，CSI：TL在其闪烁衰减中表现出强大的余辉成分，又表现出延长辐照后的严重滞后，限制了能够达到的能量分辨率以及成像质量和速度。这些缺点有效地排除了其在诸如放射性核素成像和医疗CT之类的应用中的使用，否则其低成本可能会对经济影响产生巨大的影响。 CSI：TL闪烁体的改进形式可以降低关键的挽救生命的医疗设备的成本，例如X射线CT扫描仪，荧光镜检查系统和其他依赖于快速数据获取的设备。在对CSI：TL中编码剂的合作效应的系统研究中，我们已经确定了可以抑制其余辉多达两个数量级的添加剂，同时保持其非凡的闪烁特性。我们还发现，类似的治疗方法可以减少十倍以上的滞后，这代表了几十年来一直在避开研究人员的重大突破。此外，我们已经清楚地确定，通过一种共同蒸发技术，我们可以沉积这种改良材料的厚微塞膜，该材料提供了非常高的空间分辨率，适用于使用平板检测器等新的和令人兴奋的应用程序，例如“ Nanospect”和高速锥束CT。凭借这些非凡的属性，CODOP的CSI：TL现在有助于以许多快速成像方式进行剥削，以前从中排除了CSI：TL。但是，尽管我们已经在熔体生长的晶体中实现了所有这些理想的效果，但我们尚未在单个膜组成下以令人满意的水平结合它们。这是第一阶段I的具体目标。已经确定了多组分沉积过程本身的可行性，我们将通过仔细和系统的沉积参数变化来实现此目标，例如源和底物温度，源材料基层距离，源含量距离以及来源本身的化学构成。第一阶段将产生具有闪烁特性的材料，至少与熔体生长的单晶一样好，从而立即对商业评估有用。第二阶段比第一阶段的目标要全面。在这里，我们将寻求从化学组成和物理形态方面优化材料。此外，在第I阶段的结果和大量新理论支持的投入的指导下，我们将寻求了解负责观察到的效果的机制和控制沉积过程本身的动力学因素。认识到它们的最终应用，我们将在5 x 5 cm2至50 x 50 cm2之间增长各种维度的微柱膜，并通过评估CBCT中的膜性能和操作模式来证明它们的实用性。最后，我们将通过与该技术的潜在用户合作计划来促进商业化。公共卫生相关性：广泛可用的低成本CSI：TL不仅具有出色的闪烁效率，而且可以轻松地将其作为用于高分辨率成像的大面积微型彩色膜制造，使其成为广泛应用的首选材料。不幸的是，CSI：TL在闪烁后腐烂和严重的滞后表现出强大的余辉成分，限制了可实现的能量分辨率以及成像质量和速度。这些缺点有效地排除了其在诸如放射性核素成像和医疗CT等应用中的使用，否则其低成本可能会对经济影响产生巨大的影响。 CSI：TL闪烁体的改进形式（例如这里提出的）可以降低关键的挽救生命的医疗设备的成本，例如X射线CT扫描仪，荧光镜检查系统和其他依靠快速数据获取的设备。

项目成果

Nondestructive method for quantifying thallium dopant concentrations in CsI:Tl crystals.

用于量化 CsI:Tl 晶体中铊掺杂剂浓度的无损方法。

• DOI: 10.1016/j.apradiso.2013.08.002
• 发表时间: 2013
• 期刊: Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine
• 作者: Miller,StuartR;Ovechkina,ElenaE;Bennett,Paul;Brecher,Charles
• 通讯作者: Brecher,Charles