LSO Ceramics: A New Scintillator for Medical Radiography

DESCRIPTION (provided by applicant): 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 terms of light output and timing. Only one 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 consequently the very low yield of good crystals (high light output and no afterglow). Having demonstrated in Phase I that an LSO ceramic can be made and that it has an efficiency and decay time comparable to LSO crystals, while carrying the promise of less afterglow, we wish to embark on a program of optimizing the material. One of the essential aspects is to increase the translucency to at least that of another widely used scintillator, namely GOS ceramic. This goal will be achieved through a control of the microstructure of the ceramic, involving methods, which will promote grain growth. We believe that the LSO ceramic will be appropriate in PET imaging, which now primarily uses LSO crystals, resulting in greatly reduced cost. Furthermore we believe that the ceramic will find applications in CT, where increase in speed is currently limited by the longer decay times of Cd tungstate and/or GOS.