A Digital Pulse Library for the Optimization of Signal Processing in PET

Gu, Zhichen; Prout, David; Valenciaga, Y.; Chatziioannou, Arion F.

doi:10.1109/ist.2014.6958487

Cited by 3 publications

(4 citation statements)

References 9 publications

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“…To associate a light output with each event, we used pulses from real events taken from single LYSO and BGO crystals attached to SiPMs. The SiPM outputs were fed to free running ADCs operating at 125 MHz (PicoDigitizer, Nutaq, Quebec) and a library of ∼66 K LYSO and BGO pulses was created, where each pulse was tagged by the deposited energy (Gu et al 2014).…”

Section: Geometry Setupmentioning

confidence: 99%

A digital phoswich detector using time-over-threshold for depth of interaction in PET

Prout

Shustef

et al. 2020

Phys. Med. Biol.

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We present the performance of a digital phoswich positron emission tomography (PET) detector, composed by layers of pixilated scintillator arrays, read out by solid state light detectors and an application specific integrated circuit (ASIC). We investigated the use of integrated charge from the scintillation pulses along with time-over-threshold (ToT) to determine the layer of interaction (DOI) in the scintillator. Simulations were performed to assess the effectiveness of the ToT measurements for separating the scintillator events and identifying cross-layer-crystal-scatter (CLCS) events. These simulations indicate that ToT and charge integration from such a detector provide sufficient information to determine the layer of interaction. To demonstrate this in practice, we used a pair of prototype LYSO/BGO detectors. One detector consisted of a 19 × 19 array of 7 mm long LYSO crystals (1.36 mm pitch) coupled to a 16 × 16 array of 8 mm long BGO crystals (1.63 mm pitch). The other detector was similar except the LYSO crystal pitch was 1.63 mm. These detectors were coupled to an 8 × 8 multi-pixel photon counter mounted on a PETsys TOFPET2 ASIC. This high performance ASIC provided digital readout of the integrated charge and ToT from these detectors. We present a method to separate the events from the two scintillator layers using the ToT, and also investigate the performance of this detector. All the crystals within the proposed detector were clearly resolved, and the peak to valley ratio was 11.8 ± 4.0 and 10.1 ± 2.9 for the LYSO and BGO flood images. The measured energy resolution was 9.9% ± 1.3% and 28.5% ± 5.0% respectively for the LYSO and BGO crystals in the phoswich layers. The timing resolution between the LYSO–LYSO, LYSO–BGO and BGO–BGO coincidences was 468 ps, 1.33 ns and 2.14 ns respectively. Results show ToT can be used to identify the crystal layer where events occurred and also identify and reject the majority of CLCS events between layers.

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Section: Geometry Setupmentioning

confidence: 99%

A digital phoswich detector using time-over-threshold for depth of interaction in PET

Prout

Shustef

et al. 2020

Phys. Med. Biol.

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“…As a result, the use of these recorded pulses for offline evaluation of signal processing algorithms should lead to equivalent results as those yielded from real-time, online FPGA processing. The proposed evaluation method has been consistent with the physical measurements and significantly reduces the time and effort invested [23] for reliable results.…”

Section: Synthetic Pulse Train Evaluationmentioning

confidence: 57%

“…To achieve more efficient and systematic signal processing algorithm evaluation, a collection of detector pulses from a database (usually called a digital pulse library) is required to serve as a reference data set, for which the ground truth values regarding event energy, position and timing can be known. With such a reference library, various signal processing algorithms can be tested [23]. Complicated analytical methods together with the information obtained from Monte Carlo simulations can generate simulated pulses by modeling the propagation of scintillation photons, noise and the data acquisition chain [24]- [27].…”

Section: Synthetic Pulse Train Evaluationmentioning

confidence: 99%

“…In our previous work, a comprehensive pulse library was acquired by directly recording raw pulses from physical measurements using the PETbox4 detectors and signal processing electronics [23]. This way, the pulse waveforms in the pulse library were sampled with exactly the same signal processing chain as the signals to be processed in real acquisitions in the FPGA.…”

Section: Synthetic Pulse Train Evaluationmentioning

confidence: 99%

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A New Pulse Pileup Rejection Method Based on Position Shift Identification

Prout

Taschereau

et al. 2016

IEEE Trans. Nucl. Sci.

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Pulse pileup events degrade the signal-to-noise ratio (SNR) of nuclear medicine data. When such events occur in multiplexed detectors, they cause spatial misposition, energy spectrum distortion and degraded timing resolution, which leads to image artifacts. Pulse pileup is pronounced in PETbox4, a bench top PET scanner dedicated to high sensitivity and high resolution imaging of mice. In that system, the combination of high absolute sensitivity, long scintillator decay time (BGO) and highly multiplexed electronics lead to a significant fraction of pulse pileup, reached at lower total activity than for comparable instruments. In this manuscript, a new pulse pileup rejection method named position shift rejection (PSR) is introduced. The performance of PSR is compared with a conventional leading edge rejection (LER) method and with no pileup rejection implemented (NoPR). A comprehensive digital pulse library was developed for objective evaluation and optimization of the PSR and LER, in which pulse waveforms were directly recorded from real measurements exactly representing the signals to be processed. Physical measurements including singles event acquisition, peak system sensitivity and NEMA NU-4 image quality phantom were also performed in the PETbox4 system to validate and compare the different pulse pile-up rejection methods. The evaluation of both physical measurements and model pulse trains demonstrated that the new PSR performs more accurate pileup event identification and avoids erroneous rejection of valid events. For the PETbox4 system, this improvement leads to a significant recovery of sensitivity at low count rates, amounting to about 1/4th of the expected true coincidence events, compared to the LER method. Furthermore, with the implementation of PSR, optimal image quality can be achieved near the peak noise equivalent count rate (NECR).

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Matched filter for event identification and processing in PET

Valenciaga

Prout

et al. 2012

2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record (NSS/MIC)

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A Digital Pulse Library for the Optimization of Signal Processing in PET

Cited by 3 publications

References 9 publications

A digital phoswich detector using time-over-threshold for depth of interaction in PET

A digital phoswich detector using time-over-threshold for depth of interaction in PET

A New Pulse Pileup Rejection Method Based on Position Shift Identification

Matched filter for event identification and processing in PET

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