Simulation, development and testing of a PET detector prototype using monolithic scintillator crystals treated with the sub-surface engraving technique

Pixelated scintillator crystals are commonly used in gamma radiation detectors for PET scanners. The size of these pixels, the crystal surface treatment and the thickness of the reflector inserted between crystals directly affects energy and spatial resolution as well as the sensitivity of the detector, and increase the signal to noise ratio by channeling the visible light produced by the gamma photon. Pixel fabrication is laborious, complex and expensive. Our goal is to develop a PET detector prototype with a monolithic scintillator crystal that has been pixelated using sub-surface laser engraving (SSLE) with a Nd:YAG laser. Design and distribution of pixels is based on the results of light propagation simulations. As a first step, we evaluated our simulations and surface treatment techniques on common scintillating crystals such as BGO, GSO and LYSO. In order to assess the reflective quality of the engraved surfaces measurement and analysis methods were developed based on the analysis of microscopy images of surfaces generated with different engraving protocols. Our results demonstrate that pixels engraved with this method can also be configured to compensate for the multiplexed readout penalties and preserve the detector performance.