Panetta J V, Surti S, Singh B, Karp J S
Department of Physics, University of Pennsylvania, Philadelphia, PA 19104 USA.
Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104 USA.
IEEE Trans Radiat Plasma Med Sci. 2019 Sep;3(5):531-537. doi: 10.1109/trpms.2018.2875156. Epub 2018 Oct 10.
Several groups are actively investigating the performance of monolithic (continuous) scintillation detectors using a variety of crystal thicknesses, photo-sensor configurations, and surface treatments. This work explores the performance of thick LYSO crystals that would be applicable to a whole-body PET system. The crystals were etched with laser induced optical barriers (LIOBs) to alter the behavior of the light spread within the crystal in order to improve the performance of the detector. We studied the behavior of the LIOBs in response to optical light using small cubes of LYSO with a variety of laser etching parameters to characterize the impact of the optical barriers. We demonstrated that the opacity of the etchings can be altered by varying the parameters of the laser etching, which influences the depth-dependent light response and spatial resolution in the thick crystal. We successfully etched several crystals, as large as 50×50×25-mm thick, with a fine grid of LIOBs, and achieved an average spatial resolution close to 3 mm (FWHM) with 511-keV gammas.
几个研究小组正在积极研究使用各种晶体厚度、光电传感器配置和表面处理的单片（连续）闪烁探测器的性能。这项工作探索了适用于全身PET系统的厚LYSO晶体的性能。通过激光诱导光学屏障（LIOB）对晶体进行蚀刻，以改变光在晶体内传播的行为，从而提高探测器的性能。我们使用具有各种激光蚀刻参数的LYSO小立方体研究了LIOB对光的响应行为，以表征光学屏障的影响。我们证明，通过改变激光蚀刻参数可以改变蚀刻的不透明度，这会影响厚晶体内与深度相关的光响应和空间分辨率。我们成功地用LIOB细网格蚀刻了几块尺寸达50×50×25毫米厚的晶体，并在511千电子伏特伽马射线情况下实现了接近3毫米（半高宽）的平均空间分辨率。
