Multibeam healing for laser micromachining of scintillator arrays

Cost-effective, high-performance detectors are in high demand for use in positron emission tomography (PET) and other clinical and pre-clinical nuclear medicine imaging systems. Such detectors require high-resolution, high-sensitivity pixelated scintillator arrays. Scintillators with high stopping power, such as lutetium oxyorthosilicate (LSO) and lutetium-yttrium oxyorthosilicate (LYSO), are widely used in PET. However, the mechanical pixelation of such materials (especially to achieve <;1×1 mm² pixels), yield issues, and their assembly into arrays is expensive and results in small fill factors (large inter-pixel gaps) and, hence, lower detector sensitivity than desired. Laser pixelation of scintillator material can potentially increase scintillator fill factor, resulting in higher sensitivity and yield and lower costs. We have adopted a multibeam laser micromachining approach to pixelate LSO with enhanced yield and improved throughput. The results of the experiments and the finite-element modeling are discussed here.