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: 7537767
• 负责人: VIVEK V NAGARKAR
• 金额: $ 18万
• 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 2011-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7537767
• 关键词: Address; Affect; Ants; Area; Arts; Attention; Ceramics; Characteristics; Charge; Chemicals; Classification; Color; Commit; Communities; Complement; Complex; Condition; Conflict (Psychology); Connecticut; Cost Savings; Crystallization; Data; Defect; Deposition; Development; Device Designs; Devices; Diagnostic; Diagnostic radiologic examination; Digital Mammography; Digital Radiography; Dimensions; Discipline of Nuclear Medicine; Dose; Due Process; Dura Mater; Economics; Elements; Equilibrium; Equipment; Error Sources; Evaluation; Exhibits; Exposure to; Film; Fluoroscopy; Gamma Rays; Goals; Government; Grant; Growth; Hand; Hawaii; Image; Individual; Industry; Ions; Joints; Kinetics; Knowledge; Left; Legal patent; Letters; Life; Light; Measurement; Medical; Medical Imaging; Melanocytic nevus; Mining; Modality; Mole the mammal; Morphology; Nature; Nuclear; Numbers; Operative Surgical Procedures; Output; Patients; Performance; Persons; Phase; Photons; Physics; Physiologic pulse; Positron-Emission Tomography; Process; Property; Public Health; Pulse taking; Purpose; Radiation; Radionuclide Imaging; Range; Rate; Recycling; Reporting; Research; Research Personnel; Residual state; Resolution; Right-On; Saints; Sampling; Scanning; Security; Shadowing (Histology); Silicon; Source; Specimen; Spectrum Analysis; Speed; Standards of Weights and Measures; Structure; System; Techniques; Technology; Temperature; Thermodynamics; Thick; Thoracic Radiography; Time; Uncertainty; Variant; Vendor; X-Ray Computed Tomography; X-Ray Computed Tomography Scanners; attenuation; base; commercial application; commercialization; concept; cone-beam computed tomography; cooperative study; cost; data acquisition; day; density; desire; detector; evaporation; experience; improved; insight; interest; irradiation; mathematical model; melting; millisecond; novel; peer; professor; programs; sensor; single photon emission computed tomography; success; tomography; vapor

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外来的新闪烁材料，但在性能和多功能性方面甚至很少接近CsI：Tl。CsI：Tl不仅具有极好的闪烁效率，而且可以容易地制造成用于高分辨率成像的大面积微柱膜，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的余辉成分，并且在长时间照射后表现出严重的滞后，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学CT的应用中的使用，在这些应用中，其低成本可能具有巨大的经济影响。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，荧光透视系统和其他依赖于快速数据采集的设备。在CsI：Tl中共掺杂剂的协同效应的系统研究中，我们已经确定了可以抑制其余辉的添加剂，其余辉可以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，类似的治疗可以减少滞后超过十倍，代表了一个重大突破，几十年来一直困扰着研究人员。此外，我们已经清楚地确定，通过共蒸发技术，我们可以存款厚微柱膜的这种改性材料，它提供了非常高的空间分辨率适合于这种新的和令人兴奋的应用，如“纳米SPECT”和高速锥束CT使用平板探测器。有了这些特殊的属性，共掺杂的CsI：Tl现在准备在许多快速成像模式，CsI：Tl以前被排除在外的开发。但是，虽然我们在熔融生长晶体中实现了所有这些理想的效果，但我们还没有在单一的薄膜成分中以令人满意的水平将它们结合起来;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，我们将通过仔细和系统地改变沉积参数（例如源和衬底温度、源-衬底距离和源本身的化学组成）来实现这一目标。第一阶段将生产具有闪烁特性的材料，其闪烁特性至少与熔融生长的单晶一样好，从而立即可用于商业评估。第二阶段的目标远比第一阶段全面。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的理论支持的指导下，我们将寻求理解负责观察到的效应和支配沉积过程本身的动力学因素的机制。认识到他们的最终应用，我们将生长微柱膜的各种尺寸范围从5 × 5厘米2至50 × 50厘米2，并证明其效用，通过评估膜性能CBCT和SPECT操作模式。最后，我们将通过与该技术的潜在用户的合作计划促进商业化。公共卫生关系：广泛使用的低成本CsI：Tl不仅具有极好的闪烁效率，而且可以容易地制造成用于高分辨率成像的大面积微柱膜，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。这些缺点有效地排除了其在诸如放射性核素成像和医学CT的应用中的使用，在这些应用中，其低成本可能具有巨大的经济影响。改进形式的CsI：Tl闪烁体，例如本文提出的闪烁体，可以降低关键救生医疗设备的成本，例如X射线CT扫描仪、荧光透视系统和依赖于快速数据采集的其他设备。