A New Scintillator Material for Medical Radiography

我们建议对由LSO：Ce组成的陶瓷闪烁体进行研究和开发。众所周知，晶体LSO在光输出和定时方面是最高性能的光调制器之一。唯一的障碍是LSO在大多数医疗应用领域占据主导地位：其不可接受的高成本，这主要是由于生长晶体所需的非常高的温度以及因此良好晶体的产量非常低（高光输出和无余辉）。然而，陶瓷加工提供了一种低成本的替代方案，正如我们在Lu2O3透明陶瓷发光器方面的成功所证明的那样。陶瓷制造在低得多的温度下进行，这将大大降低引起余辉的缺陷的浓度。初步工作表明，陶瓷LSO确实可以制备出与良好晶体几乎相同的光输出。虽然其非立方结构阻碍了完全透明，但LSO应容易达到目前在CT中使用的Gd2O2S：Pr的半透明水平。这将提供在CT中大大上级Gd2O2S和CdWO4的闪烁体，并且完全适用于PET和其他用途，其成本显著低于单晶。拟议的商业应用：由于目前可用的闪烁体材料不能提供必要的性能，医疗射线照相术一直无法挖掘数据采集和处理的数字技术的全部潜力。开发一种能够满足这一需求的材料将彻底改变放射技术，并大大提高其诊断能力。直接市场包括静态和断层成像，X射线和核源，并可能扩展到目前使用的几乎每一台X射线机。

We propose to conduct research and development towards a ceramic scintillator composed of LSO:Ce. It is well known that crystalline LSO is one of the highest performance scintillators in term of light output and timing. Only impediment stands in the way of LSO assuming a commanding position in most areas of medical applications: its unacceptably high cost, which is due largely to the very high temperatures necessary to grow the crystals and the consequently very low yield of good crystals (high light output and no afterglow). Ceramic processing, however, offers a low-cost alternative, as demonstrated by our success with transparent ceramic scintillators of Lu2O3- Ceramic fabrication takes place at a much lower temperature, which should substantially reduce the concentration of defects that give rise to afterglow. Preliminary work indicates that ceramic LSO can indeed be prepared with light output nearly the same as from good crystals. While its non- cubic structure prevents full transparency, LSO should readily reach the translucency levels of Gd2O2S:Pr, currently used in CT. This would provide a scintillator vastly superior to Gd2O2S and CdWO4 in CT and fully applicable to PET and other uses, at costs significantly lower than for single crystals. PROPOSED COMMERCIAL APPLICATIONS: Because currently available scintillator materials cannot provide the necessary performance, medical radiography has been unable to tap the full potential of digital techniques for data acquisition and processing. The development of a material that can fill this need will revolutionize radiological techniques and greatly enhance their diagnostic power. The immediate market includes both static and tomographic imaging, X-ray and nuclear sources, and potentially extends to virtually every X-ray machine now in use.