In this study we developed a prototype animal Family pet through

In this study we developed a prototype animal Family pet through the use of several book technologies to utilize the solid-state photomultiplier (SSPM) arrays for measuring the depth-of-interaction AT-406 (DOI) and improving imaging performance. mm2 and its own output can be read with a custom-developed application-specific-integrated-circuit (ASIC) to straight convert analog indicators to digital timing pulses that encode the discussion info. These pulses are used in and become decoded with a field-programmable-gate-array (FPGA) centered time-to-digital convertor for coincident event selection and data acquisition. The 3rd party readout of every SSPM as well as the parallel sign process can considerably enhance the signal-to-noise ratio and enable using flexible algorithms for different data processes. The prototype PET consists of two rotating detector panels on a portable gantry with four detectors in each panel to provide 16 mm axial and variable transaxial field-of-view (FOV) sizes. List-mode ordered-subset-expectation-maximization image reconstruction was implemented. The measured mean energy coincidence timing and DOI resolution for a crystal were about 17.6% 2.8 ns and 5.6 mm respectively. The measured transaxial resolutions AT-406 at the center of the FOV were 2.0 mm and 2.3 mm for images reconstructed with and without DOI respectively. In addition the resolutions across the FOV with DOI were substantially better than those without DOI. The quality of PET images of both a hot-rod phantom and mouse acquired with DOI was much higher than that of images obtained without DOI. This study demonstrates that SSPM arrays and advanced readout/processing electronics can be used to develop a practical DOI-measureable PET scanner. and directions respectively. The ratio of signals measured using SSPM arrays 1 and 2 for each event is calculated as follows: is then converted to DOI using a method based on LYSO scintillator background radiation developed in our laboratory (Shao et al. 2008 Bircher and Shao 2012 A list-mode-based OSEM image reconstruction algorithm (Reader et al. 2002 was implemented. Each OSEM subset was simply an equal fraction of total accumulated events divided in sequential list-mode order without other constraints. An image-resolution smoothing (1.5 mm) was applied after each iteration to partially compensate for nonuniform image resolution from the flat-panel rectangular system configuration. The image reconstruction was implemented on a graphics processing unit platform (CUDA; NVIDIA) to accelerate the reconstruction. Pictures obtained without usage of DOI were reconstructed for assessment. A simulation-generated three-dimensional level of sensitivity map was validated using premeasured phantom data and found in picture reconstruction to pay for sensitivity variants over the FOV. 2.4 Detector Efficiency Measurement Crystal Recognition and Energy Quality For every detector module a flood-source crystal map was obtained from an external 137Cs resource (mono-energy maximum 662 keV) and utilized to attract boundaries among AT-406 crystals for preliminary crystal identification. Another flood-source crystal map was obtained from an exterior 22Na resource and utilized to calibrate the power scales RTS connected with each crystal through the use of both 511 and 662 keV peaks through the obtained energy spectra. Following the energy-scale calibration a power windowpane (400-650 keV) was put on the next map to generate the ultimate crystal map to get a crystal lookup desk. The crystal of every interaction was decided on out of this crystal map as well as the related DOI placement was calculated based on the sign percentage R measured from two SSPM arrays. Coincidence Timing Energy and DOI Resolutions These detector-level resolutions had been assessed using an exterior electronic collimation solution to go for relationships within a slim DOI area (Moses et al. 1995 Shao et al. 2007 A supplementary single-channel detector comprising a 1×1×10 mm3 LYSO crystal in conjunction with an SSPM was utilized to collimate the DOI from the detector component to be assessed having a 22Na drive resource (1 mm width 5 mm size) positioned between them. The tiny LYSO crystal was exactly aligned using its lengthy axis inside the AT-406 disk-source aircraft to supply a thin lover beam to irradiate a slim DOI region for a number of crystals in the detector component. The excess detector and 22Na resource had been stepped together in one end from the detector module towards the additional end at different crystal depths as well as the signals through the detector module.