Positron emission tomography detector performance with different crystal pitches

Abstract

Aims: In this work, we evaluated the performance of three pitches positron emission tomography (PET) detectors for building a high-resolution small-animal PET imaging experimental platform. Methods: The evaluation of PET detectors includes twodimensional crystal identification, energy resolution, and crystal look-up table. The nuclear instrumentation module and PXI data acquisition (DAQ) system were both used to obtain flood images. The energy spectrum of the Na-22 source was measured. PET detectors of 2.0 and 1.6 mm pitches used in our present experiment were composed of lutetium yttrium oxyorthosilicate (LYSO) crystals directly coupled to position-sensitive photomultiplier tubes (PSPMTs). The 1.3-mm pitch detector comprises a LYSO crystal, a tapered light-guide, and a PSPMT. The crystal sizes of the detectors were a 10 × 10 array of 2.0 × 2.0 × 10 mm 3 crystals, a 10 × 10 array of 1.6 × 1.6 × 10 mm 3 crystals, and an 18×18 array of 1.3×1.3×10 mm 3 crystals, respectively. Due to the lower sampling frequency of the DAQ system, a spline interpolation algorithm was introduced in the signal waveform to reconstruct the peak values. Results: The experimental results indicated that all three PET detector crystals could be clearly identified. A detailed analysis demonstrated that the key characteristic full width at half maximum (FWHM) values of the crystals profile could reach 0.46 ± 0.03, 0.32 ± 0.03, and 0.21 ± 0.02 mm, while the crystal average energy resolutions were 16.8% ± 1.76%, 20.1% ± 2.24%, and 31.5% ± 3.76%, which correspond to B YongZhi Yin yinyzh@lzu.edu.cn 1 School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000, China pitches of 2.0-, 1.6-, and 1.3-mm, respectively. Conclusions: The PET detector modules of LYSO crystal arrays could be potentially used in the small-animal PET imaging applications and are promising to achieve submillimeter PET images.

Compact pixelated scintillator detector investigation for gamma ray detection

“…For example, gadolinium oxysulfide (GOS) [6], NaI [7], gadolinium aluminum gallium garnet (GAGG) [8] and GE Gemstone [9] for computed tomography (CT) have good properties of high light output, high x-ray stopping power, short primary decay time, low afterglow, radiation damage resistance, light-output stability, compact packaging, and easy machining [10]. Scintillators, such as LYSO, LFS, LSO, LaBr 3 , CeBr 3 and GAGG, with various types, sizes, and shapes are widely used in positron emission tomography (PET) [11][12][13][14].…”