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Abstract
In this study, we propose a linear field-programmable gate array (FPGA)-based charge measurement method by combining a charge-to-time converter (QTC) with a single-ended memory interface (SeMI) input receiver. The QTC automatically converts the input charge into a dual-slope pulse, which has a width proportional to the input charge. Dual-slope pulses are directly digitized by the FPGA input/output (I/O) buffers configured with SeMI input receivers. A proof-of-concept comparator-less QTC/SeMI data acquisition (DAQ) system, consisting of 132 energy and 33 timing channels, was developed and applied to a prototype brain-dedicated positron emission tomography (PET) scanner. The PET scanner consisted of 14 sectors, each containing 2 × 1 block detectors, and each block detector yielded four energy signals and one timing signal. Because a single QTC/SeMI DAQ system can receive signals from up to eight sectors, two QTC/SeMI DAQ systems connected using high-speed gigabit transceivers were used to acquire data from the PET scanner. All crystals in the PET block detectors, consisting of dual-layer stacked lutetium oxyorthosilicate (LSO) scintillation crystal and silicon photomultiplier arrays, were clearly resolved in the flood maps with an excellent energy resolution. The PET images of hot-rod, cylindrical, and two-dimensional Hoffman brain phantoms were also acquired using the prototype PET scanner and two QTC/SeMI DAQ systems.

Affiliation

Jun Yeon Won  1 , Guen Bae Ko, Kyeong Yun Kim, Haewook Park, Seungeun Lee, Jeong-Whan Son, Jae Sung Lee
1 Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul 03080, Korea. Institute of Radiation Medicine, Medical Research Center, Seoul National University College of Medicine, Seoul 03080, Korea. Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 03080, Korea.