Low Cost Co Doped Scintillator for Medical CT

用于医疗 CT 的低成本掺钴闪烁体

• 批准号: 7108374
• 负责人: MICHAEL R. SQUILLANTE
• 金额: $ 11.94万
• 依托单位: RADIATION MONITORING DEVICES, INC.
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-01 至 2007-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7108374
• 关键词: ions; lighting; performance

DESCRIPTION (provided by applicant): Although CsI:TI is one of the most desirable scintillators for a broad range of medical and industrial diagnostics, it has never been applicable to X-ray computerized tomography (CT). Despite the otherwise superb properties of CsI, it suffers from a persistent afterglow that simply does not decay fast enough to provide rapid framing rates without unacceptable carryover of the previous image. We have discovered that it is possible to suppress the afterglow of Csl:TI by as much as two orders of magnitude if a suitable modifier ion is inserted into the host lattice. The suppressive effect, however, is opti- mal for only short excitation pulses, and falls off sharply for extended exposures (> 6s) and radiation dose (>6R/s). characteristic of CT scans. Only one ion appears to retain this afterglow-suppressive capability under the conditions actually imposed during CT scans. We intend to investigate the effect of this ion on scintillation properties of Csl. The proposed Phase I research will primarily focus on growing codoped Csl:TI crystals with variations in composition to determine the range over which the maximum beneficial effects of reduced afterglow can be obtained without sacrificing the other excellent properties of the Csl:TI. These crystals will be subjected to extended exposures at high x-ray dose rates, and their scintillation properties will be evaluated before, during, and after such exposure. Changes in the afterglow and the emission efficiency will be measured to demonstrate the feasibility of our approach. For Phase I, we will seek to reduce the Csl:TI afterglow 2 ms after excitation to a level of 0.2% or lower, with an ultimate goal at least a factor of four below that. In addition, guided by the experimental results, we will seek both to understand the mechanisms responsible for the observed effect and to explore the possibility of enhancing it through the cooperative influence of an additional codopant. The success of this research will provide CT with the superior scintillation properties of Csl with low afterglow and at a cost far below scintillators now in use.

描述（由申请人提供）：尽管CSI：TI是广泛的医疗和工业诊断范围最受欢迎的闪光灯之一，但它从来都不适用于X射线计算机层析成像（CT）。尽管CSI的特性除外，但它具有持续的余辉遭受的痛苦，它根本不够快地腐烂，无法提供快速的框架速率，而不会无法接受以前的图像。我们已经发现，如果将合适的修饰符离子插入宿主晶格，则可以将CSL：Ti的余辉抑制多达两个数量级。然而，抑制作用仅是对短激发脉冲的光学效果，而对于扩展的暴露（> 6s）和辐射剂量（> 6R/s）而急剧下降。 CT扫描的特征。在CT扫描过程中实际施加的条件下，似乎只有一个离子保留了这种造影抑制能力。我们打算研究该离子对CSL闪烁特性的影响。提出的I期研究将主要集中在成长的CODOP的CSL：Ti晶体上，其组成方面有变化，以确定可以在不牺牲CSL：Ti的其他优秀特性的情况下获得减少余辉的最大有益作用的范围。这些晶体将在高X射线剂量速率下进行延长的暴露，并在暴露之前，之中和之后评估它们的闪烁特性。余辉和排放效率的变化将测量以证明我们方法的可行性。对于第一阶段，我们将寻求将激发后2 ms的CSL：Ti余辉降低到0.2％或更低的水平，最终目标至少低于该水平。此外，在实验结果的指导下，我们将寻求了解负责观察到的效果的机制，并探索通过额外的代码剂的合作影响来增强它的可能性。这项研究的成功将为CT提供CSL的出色闪烁特性，其余辉低，并且以远低于目前正在使用的闪光灯的成本。

项目成果

A Tunneling Model for Afterglow Suppression in CsI:Tl,Sm Scintillation Materials.

• DOI: 10.1016/j.radmeas.2009.11.010
• 发表时间: 2010-03
• 期刊: Radiation measurements
• 影响因子: 2
• 作者: Kappers LA;Bartram RH;Hamilton DS;Lempicki A;Brecher C;Gaysinskiy V;Ovechkina EE;Thacker S;Nagarkar VV
• 通讯作者: Nagarkar VV