Detection performance of pixelated lutetium–yttrium oxyorthosilicate (LYSO) scintillators for high-resolution photon-counting CT imaging

Abstract

High-resolution photon-counting detector (PCD) computed tomography (CT) imaging is increasingly used for several applications. Recent technological advances in CT instrumentation have introduced various types of radiation detectors. Therefore, this work aims at evaluating the lutetium–yttrium oxyorthosilicate (LYSO) scintillator for use in PCD CT from a detector point of view. To do so, a mini-CT prototype was designed and constructed based on the pixelated LYSO blocks. The detector comprises four 10 × 10 linearly arranged LYSO blocks coupled with four position-sensitive photomultiplier tubes. The prototype utilizes a point gamma-ray source along with a cone-beam collimator. An in-home MATLAB-based data processing software package was also developed for storing the list-mode data, event positioning, and energy windowing. A set of experiments were conducted to assess the performance of the constructed energy-resolved LYSO:Ce detector for mini-CT imaging. The results show good crystal identification for all blocks with a maximum peak-to-valley ratio of 3.48. In addition, the findings confirm that the developed detector is position-sensitive. The 20% energy window provides an optimal performance by simultaneously providing good crystal identification and a scatter removal factor of 0.71. A 96% uniformity was also observed when the detector was irradiated with a uniform flood. The spatial resolution of the mini-CT prototype in the x- and y-directions was calculated to be 0.9 and 0.93 mm, respectively, corrected for a magnification factor of 2.5. It is concluded that the pixelated LYSO crystal is a promising alternative to the current detectors and would be the scintillator of choice for high-resolution PCD CT imaging tasks.

Strain-Released Cs5Cu3Cl6I2 Scintillators by Rb+ Doping for High-Resolution X-Ray Imaging

“…X-ray detection technologies play a crucial role in various applications, including medical imaging, nondestructive testing, and security inspection. − Scintillation X-ray detectors are widely utilized, and scintillators are essential components of these detectors. − Traditional scintillators like CsI:TI OS:Tb, NaI:TI, and LYSO:Ce are commercially available. − However, these scintillators face challenges, such as a complex preparation process, high cost, light scattering, long afterglow, and poor stability, limiting their widespread application. − Moreover, the incorporation of toxic elements like TI in high-performance scintillators poses significant safety risks . Therefore, there is an immediate need to investigate advanced scintillator materials with high performance.…”