Experimental results with TOFPET2 ASIC for time-of-flight applications

Bugalho, R.; Francesco, A. Di; Ferramacho, L.; Leong, C.; Niknejad, T.; Oliveira, Luís B.; Pacher, L.; Rolo, M.; Rivetti, A.; Silveira, M.; Silva, José C.; Silva, Rui; Tavernier, S.; Varela, J.

doi:10.1016/j.nima.2017.11.034

Cited by 41 publications

(26 citation statements)

References 3 publications

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“…The pre-amplifier is a low-impedance current conveyor [42]. In current-sensing, a low input stage impedance resulting in fast pulses is beneficial for the timing resolution [29]. In contrast a higher input stage impedance results in the slower and higher rise of the acquired pulses.…”

Section: Discussionmentioning

confidence: 99%

Investigation of the Power Consumption of the PETsys TOFPET2 ASIC

Nadig

Weissler

Radermacher

et al. 2020

IEEE Trans. Radiat. Plasma Med. Sci.

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In state-of-the-art positron emission (PET) tomography systems, application-specific integrated circuits (ASICs) are commonly used to precisely digitize the signals of analog silicon photo-multipliers (SiPMs). However, when operating PET electronics in a magnetic resonance (MR) system, one faces the challenge of mutual interference of these imaging techniques. To prevent signal deterioration along long analog signal lines, PET electronics with a low power consumption digitizing the signals close to the SiPMs are preferred. In this study, we evaluate the power consumption of the TOFPET2 ASIC. Its power consumption ranges from 3.6 mW/channel to 7.2 mW/channel as a function of the input stage impedance and discriminator noise settings. We present an analytical model allowing to compute the power consumption of a given ASIC configuration. The configured input stage impedance and discriminator noise have an impact on the coincidence resolution time, energy resolution, and dark count rate. Since TOFPET2 ASICs delivers state-ofthe art performance with a power consumption similar or even lower than other ASICs typically used for PET applications, it is a favorable candidate to digitize the signals of SiPMs in future simultaneous PET/MR systems.

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Section: Discussionmentioning

confidence: 99%

Investigation of the Power Consumption of the PETsys TOFPET2 ASIC

Nadig

Weissler

Radermacher

et al. 2020

IEEE Trans. Radiat. Plasma Med. Sci.

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“…Hot (respectively cold) lesions are considered as detected if their intensity profiles were visibly distinguishable above (or below for cold features) the background signal level. The simulated acquisition time is 100 s, using 18 F considering a continuum positron energy spectrum in water with the maximum end-point energy of 0.634 MeV as implemented in the PENELOPE code. The considered scintillators for the simulations are LYSO crystals (7.1 g/cm 3 ).…”

Section: Scanner Simulations With Different Tof Valuesmentioning

confidence: 99%

“…The width of the Gaussian distribution, and thus the spatial uncertainty of the annihilation point along the LOR, is directly proportional to the time resolution of the detection system. TOF information provides a better estimation of the position of the annihilation process along the LOR compensating, in part, the lack of angular information produced by the open geometries, reducing artifacts in the reconstructed images, and improving the image quality [13,14].Currently, commercial TOF dedicated electronics reach time resolutions in the range of 200-400 ps [15,16] even though experimental systems have reached up to 150 ps with only two detector blocks [17][18][19].In this context, our study aims to determine the optimal geometry for a dedicated open cardiac PET device considering different TOF resolutions. We simulated different open geometries and compared them with a full ring design.…”

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confidence: 99%

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Simulation Study for Designing a Dedicated Cardiac TOF-PET System

Oliver

Moliner

Ilisie

et al. 2020

Sensors

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The development of dedicated positron emission tomography scanners is an active area of research, especially aiming at the improvement of lesion detection and in support of cancer treatment and management. Recently, dedicated Positron Emission Tomography (PET) systems with different configurations for specific organs have been developed for improving detection effectiveness. Open geometries are always subject to distortion and artifacts in the reconstructed images. Therefore, the aim of this work is to determine the optimal geometry for a novel cardiac PET system that will be developed by our team, and determine the time resolution needed to achieve reasonable image quality for the chosen geometry. The proposed geometries consist of 36 modules. These modules are arranged in two sets of two plates, each one with different configurations. We performed Monte Carlo simulations with different TOF resolutions, in order to test the image quality improvement in each case. Our results show, as expected, that increasing TOF resolution reduces distortion and artifact effects. We can conclude that a TOF resolution of the order of 200 ps is needed to reduce the artifacts, to acceptable levels, generated in the simulated cardiac-PET open geometries. distortion effects in the final reconstructed images. Time of flight (TOF) information provided by the detectors plays an important role in the reduction of these non-desired effects for open PET geometries.PET detection is based on the concept of Line Of Response (LOR). When two annihilation photons simultaneously impact two different detectors within a predetermined time-window (coincidence window), we consider that an event has occurred along this LOR. If TOF information is not available, the annihilation process is equiprobable all along the LOR, as there is no time information corresponding to the gamma ray impact. When introducing TOF information, it allows for the assignment of a Gaussian probability for a region of the LOR that contains the annihilation point. The width of the Gaussian distribution, and thus the spatial uncertainty of the annihilation point along the LOR, is directly proportional to the time resolution of the detection system. TOF information provides a better estimation of the position of the annihilation process along the LOR compensating, in part, the lack of angular information produced by the open geometries, reducing artifacts in the reconstructed images, and improving the image quality [13,14].Currently, commercial TOF dedicated electronics reach time resolutions in the range of 200-400 ps [15,16] even though experimental systems have reached up to 150 ps with only two detector blocks [17][18][19].In this context, our study aims to determine the optimal geometry for a dedicated open cardiac PET device considering different TOF resolutions. We simulated different open geometries and compared them with a full ring design. As a consequence of this study, a prototype device will be developed according to the optimal configuration determined in terms of g...

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“…There are benchtop experiments which can achieve coincidence time resolutions below 100 ps [17], [18]. On system level, several TOF-PET-ASIC-development projects aim to allow for a CRT better than 300 ps or even as low as 200 ps [19]- [21]. Energy can be measured using a second timestamp on the falling edge of the SiPM signal.…”

Section: Introductionmentioning

confidence: 99%

Initial Measurements with the PETsys TOFPET2 ASIC Evaluation Kit and a Characterization of the ASIC TDC

Schug

Nadig

Weissler

et al. 2019

IEEE Trans. Radiat. Plasma Med. Sci.

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For a first characterization, we used the two KETEK-PM3325-WB SiPMs each equipped with a 3 mm × 3 mm × 5 mm LYSO scintillation crystal provided with the PETsys TOFPET2 ASIC Evaluation Kit. We changed the lower of two discriminator thresholds (D T1) in the timing branch from vth t1 = 5-30. The overvoltage was varied in a range of 1.25 V-7.25 V. The ambient temperature was kept at 16 • C. For all measurements, we performed an energy calibration including a correction for saturation. We evaluated the energy resolution, the coincidence resolving time (CRT) and the coincidence rate. At an overvoltage of 6 V, we obtained an energy resolution of about 10% FWHM, a CRT of approximately 210 ps FWHM and 400 ps FWTM, the coincidence rate showed only small variations of about 5%. To investigate the influence of the ambient temperature, it was varied between 12 • C-20 • C. At 12 • C and an overvoltage of 6.5 V, a CRT of approx. 195 ps FWHM and an energy resolution of about 9.5% FWHM could be measured. Observed satellite peaks in the time difference spectra were investigated in more detail. We could show that the location of the satellite peaks is correlated with a programmable delay element in the trigger circuit.

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Experimental results with TOFPET2 ASIC for time-of-flight applications

Cited by 41 publications

References 3 publications

Investigation of the Power Consumption of the PETsys TOFPET2 ASIC

Investigation of the Power Consumption of the PETsys TOFPET2 ASIC

Simulation Study for Designing a Dedicated Cardiac TOF-PET System

Initial Measurements with the PETsys TOFPET2 ASIC Evaluation Kit and a Characterization of the ASIC TDC

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