Afterglow CsI(Tl) Scintillator for Medical Applications

描述(申请人提供)：掺铊的碘化铯是目前使用的最重要的闪烁体之一。在将电离辐射转化为可见光子方面，它无疑是效率方面的领先者。此外，它的高密度、高原子序数、优异的光传输性能、高抗辐射性、易获得和低成本使其适合于广泛的应用，如医学成像和高能物理。 CSI(TL)的一个特性限制了它在快速或时间分辨应用中的使用，那就是它的余辉。这导致了高计数率应用中的问题、CT使用中的重建伪影以及高速成像中对比度降低和图像模糊的问题。如果CsI(Tl)中的余辉被熄灭，这种材料可以在所有这些应用中有效地使用，从而在显著降低成本的同时提高系统性能。为了解决这个问题，我们建议将CSI(Tl)的余辉降到最低，使其能够在不牺牲其优异性能的情况下，适合于许多技术和商业上的重要应用。在第二阶段，我们的方法将包括详细研究CSI(T1)中的闪烁过程，并通过在其晶格中添加激活剂来猝灭余辉。潜在应用：CsI(Tl)闪烁体广泛应用于许多商业产品中，例如数字乳房X光摄影系统、图像增强管以及许多其他用于医疗和非医疗用途的系统。余辉的减少将使这种闪烁体在许多重要的成像方式中使用，例如医学CT、立体定向乳房X光照相和其他高速成像以及计数应用。在这些系统中使用CSI(TL)预计将大大提高它们的性能，并显著降低成本。

DESCRIPTION (provided by applicant): CsI doped with thallium is one of the most important scintillators currently in use. In terms of conversion of ionizing radiation to visible photons, it is the unquestioned leader in efficiency. Additionally, its high density, high atomic number, excellent light transport properties, high radiation resistance, easy availability, and low cost make it suitable for a wide variety of applications such as medical imaging and high energy physics. The one property of CsI(Tl) that limits its use in fast or time resolved applications is its afterglow. This causes problems in high count-rate applications, reconstruction artifacts in CT usage, and problems of reduced contrast and image blurring in high-speed imaging. If the afterglow in CsI(Tl) is quenched, this material could be effectively used in all these applications resulting in improved system performance with dramatic reduction in costs. To address this issue we propose to minimize the CsI(Tl) afterglow to a level where it can be suitably used for many technologically and commercially important applications, without sacrificing its excellent properties. Our approach during Phase II will involve detailed investigation of the scintillation processes in the CsI(T1) and quenching the afterglow by the addition of activators into its lattice. Potential Applications: The CsI(Tl) scintillator is widely used in many commercial products such as digital mammography systems, image intensifier tubes, and numerous other systems for medical and non-medical use. Reduction of afterglow will allow the use of this scintillator in many important imaging modalities such as medical CT, stereo-tactic mammography, and other high-speed imaging as well as counting applications. The use of CsI(Tl) in these systems is expected to substantially enhance their performance with dramatic reduction in cost.