Positron emission tomography detector performance with different crystal pitches

• Published in: Radiation detection technology and methods 2017-12, Vol.1 (2), Article 24
• Main Authors: Tong, LinGe, Fan, YaMing, Dong, Ming, Zhao, Liang, Li, ZhongXing, Li, YingGuo, Wang, TianQuan, Yin, YongZhi, Chen, XiMeng
• Format: Article
• Language: English
• Subjects: Beam Physics; Hadrons; Heavy Ions; Nuclear Energy; Nuclear Physics; Original Paper; Particle Acceleration and Detection; Physics; Physics and Astronomy
• ISSN: 2509-9930; 2509-9949
• DOI: 10.1007/s41605-017-0026-y

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 two-dimensional 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 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 sub-millimeter PET images.