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

基本信息

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
项目类别：
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

项目摘要

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）：虽然现在正在开发许多奇异的新型闪烁材料，但很少有材料在性能和多功能性方面能够接近 CsI:Tl。 CsI:Tl 以低成本在商业上广泛使用，不仅具有卓越的闪烁效率，而且可以很容易地制造为用于高分辨率成像的大面积微柱薄膜，使其成为广泛应用的首选材料。不幸的是，CsI:Tl 在闪烁衰减中表现出强烈的余辉成分，并且在长时间照射后表现出严重的滞后现象，限制了可实现的能量分辨率以及成像质量和速度。这些缺点实际上阻碍了其在放射性核素成像和医学 CT 等应用中的使用，否则其低成本可能会产生巨大的经济影响。 CsI:Tl 闪烁体的改进形式可以降低关键救生医疗设备的成本，例如 X 射线 CT 扫描仪、透视系统和其他依赖快速数据采集的设备。在对 CsI:Tl 中共掺杂剂协同效应的系统研究中，我们发现了一些添加剂，可以将其余辉抑制多达两个数量级，同时保持其非凡的闪烁特性。我们还发现，类似的治疗可以将滞后现象减少十倍以上，这是研究人员几十年来一直未能实现的重大突破。此外，我们已经清楚地确定，通过共蒸发技术，我们可以沉积这种改性材料的厚微柱薄膜，这提供了非常高的空间分辨率，适合“纳米SPECT”和高速锥束等新的和令人兴奋的应用使用平板探测器的 CT。凭借这些优异的特性，共掺杂 CsI:Tl 现在有望在许多快速成像模式中得到利用，而 CsI:Tl 以前被排除在外。但是，尽管我们已经在熔融生长晶体中实现了所有这些理想的效果，但我们尚未将它们以令人满意的水平组合在单一薄膜组合物中；这是第一阶段的具体目标。在已经确定了多组分沉积工艺本身的可行性之后，我们将通过仔细且系统地改变沉积参数（例如源和基底温度、源-基底距离以及化学成分）来实现这一目标。来源本身的组成。第一阶段将生产出闪烁性能至少与熔融生长单晶一样好的材料，从而立即可用于商业评估。第二阶段的目标比第一阶段更加全面。在这里，我们将寻求在化学成分和物理形态方面优化材料。此外，在第一阶段的结果和大量新理论支持的指导下，我们将寻求了解造成观察到的效应的机制以及控制沉积过程本身的动力学因素。认识到它们的最终应用，我们将生长各种尺寸（从 5 x 5 cm2 到 50 x 50 cm2）的微柱薄膜，并通过评估 CBCT 和 SPECT 操作模式下的薄膜性能来展示其实用性。最后，我们将通过与该技术的潜在用户的合作项目来促进商业化。公共健康相关性：广泛使用的低成本 CsI:Tl 不仅具有卓越的闪烁效率，而且可以轻松制造为用于高分辨率成像的大面积微柱薄膜，使其成为各种应用的首选材料。不幸的是，CsI:Tl 在闪烁衰减中表现出强烈的余辉成分，并且在长时间照射后表现出严重的滞后现象，限制了可实现的能量分辨率以及成像质量和速度。这些缺点实际上阻碍了其在放射性核素成像和医学 CT 等应用中的使用，否则其低成本可能会产生巨大的经济影响。 CsI:Tl 闪烁体的改进形式（例如此处提出的闪烁体）可以降低关键救生医疗设备的成本，例如 X 射线 CT 扫描仪、透视系统和其他依赖快速数据采集的设备。