Performance of a high-resolution depth-encoding PET detector module using linearly-graded SiPM arrays

Du, Junwei; Bai, Xiaowei; Gola, A.; Acerbi, Fabio; Ferri, Alessandro; Piemonte, C.; Yang, Yongfeng; Cherry, Simon R.

doi:10.1088/1361-6560/aaa707

Cited by 50 publications

(78 citation statements)

References 30 publications

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“…The 500 ps TOF was commonly available in commercial PET scanners (Jakoby et al 2011) and 320 ps TOF has also been reported in recent published work (Peng et al 2015, Miller et al 2015, Zhang et al 2018a). The choice of DOI resolutions also covered the range that had been reported in the literature (Du et al 2018, Zhang et al 2013a, Zhang et al 2013b). Two different activity levels, 20 MBq and 370 MBq, were investigated to represent a low dose and a regular clinical dose studies, respectively.…”

Section: Methodsmentioning

confidence: 99%

Theoretical study of the benefit of long axial field-of-view PET on region of interest quantification

et al. 2018

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The aim of this study is to evaluate the benefit of long axial field-of-view (AFOV) PET scanners on region of interest (ROI) quantification. We simulated a series of PET scanners with an AFOV ranging from 22 cm to 220 cm. A theoretical framework was used to predict the contrast recovery coefficient (CRC) and the variance of ROI quantification in penalized maximum likelihood (ML) image reconstruction, in which the resolution and noise tradeoff was controlled by a regularization parameter with a quadratic penalty function. The characterization was based on the converged penalized ML reconstruction with an accurate system model. We examined quantification of a 2 mm ROI and 10 mm ROI in a clinically relevant scan range of 110 cm. Multiple bed positions with 50% overlap were used for scanners with shorter AFOV to provide a relatively uniform sensitivity across the 110 cm axial range. A uniform water cylinder of 20 cm in diameter and 230 cm in length was chosen to model the attenuation and background activity. We computed the variance reduction factor at fixed resolution. Effects of different detector capabilities, including TOF (time-of-flight) resolution (320 ps, 500 ps, and non-TOF) and DOI (depth-of-interaction) resolution (4 mm, 10 mm, and no DOI), were evaluated. The results show that at a normal activity level (370 MBq), the 220 cm AFOV scanner offers a ∼17-fold variance reduction for the 2 mm ROI and ∼26-fold variance reduction for the 10 mm ROI (both measured at CRC = 0.5) over the 22 cm AFOV scanner when both using detectors with 500 ps TOF resolution no DOI capability. The variance reduction factors of trues-only are higher than those of including scatters and randoms. Combining 320 ps TOF and 4 mm DOI, the 220 cm long scanner offers a ∼45-fold variance reduction over the 22 cm long reference scanner (500 ps TOF, no DOI) for imaging 2 mm and 10 mm ROIs. The variance reduction factors are higher at a lower activity level due to lower random fraction. In conclusion, our study demonstrates that a long AFOV scanner can greatly improve the quantitative accuracy of PET imaging compared to current state-of-the-art clinical PET scanners.

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Section: Methodsmentioning

confidence: 99%

Theoretical study of the benefit of long axial field-of-view PET on region of interest quantification

et al. 2018

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“…However, the readout electronics and position estimation algorithms are more complicated and require very careful calibration compared to PET detectors based on scintillator arrays, which typically use simple center of gravity algorithms to estimate the gamma photon interaction position (Joung et al 2002, Wang et al 2011 and Du et al 2016). Furthermore, the resolution obtained from PET detectors based on thick monolithic scintillators are not in general as good as these obtained from PET detectors based on scintillator arrays (Borghi et al 2018 and Du et al 2018).…”

Section: Introductionmentioning

confidence: 73%

“…The energy resolution and peak position of the 511 keV gamma photons were extracted using the data obtain for the flood histograms. For the DOI measurements, a reference detector consisting of a 0.5 × 20 × 20 mm 3 LYSO crystal and the same PMT was used to electronically collimate the interaction depth (Du et al 2018). The PMT signal was amplified by a transimpedance amplifier (based on AD8045) and then fed in to a CFD (ORTEC 584) for time pick-off.…”

Section: Methodsmentioning

confidence: 99%

“…To obtain uniform resolution across the field of view (FOV), PET detector modules with depthof-interaction (DOI) information are required. PET detectors based on dual-ended readout method have been demonstrated to have excellent DOI resolution (Yang et al 2009 and Du et al 2018). Figure 1 (top row) shows a schematic of a PET scanner based on detectors with dual-ended readout using silicon photomultipliers (SiPMs).…”

Section: Introductionmentioning

confidence: 99%

“…This results in a low packing fraction and makes the gaps between the detector modules even larger. Tapered scintillator array and position-sensitive APDs or position- sensitive SiPMs have been used to reduce the gaps, but the gaps are not eliminated (Yang et al 2009 and Du et al 2018).…”

Section: Introductionmentioning

confidence: 99%

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Shared-photodetector readout to improve the sensitivity of positron emission tomography

Peng

Bai

et al. 2018

Phys. Med. Biol.

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Sensitivity is an important performance characteristic of positron emission tomography (PET) systems. Improved sensitivity can be used to reduce injected dose, reduce scan time, or improve the signal-to-noise ratio and temporal resolution for dynamic studies. One way to improve the sensitivity of PET scanners is to reduce the gaps between detector modules. In this paper, a new signal processing method, named the shared-photodetector readout method, is proposed and evaluated. In this method, the signals generated in nearest neighbor photodetectors adjacent to the detector module of interest, were used to help identify the interaction location in the detector module of interest. Using this method, scintillator array-based detector modules with almost 100% packing fraction can be built, and the edge crystals can be clearly resolved, even when the crystals are small compared to the photodetector size. To evaluate this signal processing concept in one dimension, a detector block with four dual-ended readout detector modules, was designed. The detector block consisted of eight 4 × 4 arrays of SensL MicroFJ-30035 SiPMs coupled to both ends of a 14 × 56 array of 0.9 × 0.9 × 20 mm LYSO elements with a pitch size of 0.96 mm and a length of 20 mm. Performance in terms of energy resolution, flood histogram, timing resolution and depth-of-interaction resolution obtained using the shared-photodetector readout method were compared to those obtained using a conventional readout method. The results show that better over-all performance was achieved using the shared-photodetector readout method, especially at the edges and corners of the array.

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Readout Strategies and Asynchronous Architectures

Dandin,

McFarlane,

Sajal

et al. 2024

Single-Photon Avalanche Diodes and Photon Counting Systems

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Performance of a high-resolution depth-encoding PET detector module using linearly-graded SiPM arrays

Cited by 50 publications

References 30 publications

Theoretical study of the benefit of long axial field-of-view PET on region of interest quantification

Theoretical study of the benefit of long axial field-of-view PET on region of interest quantification

Shared-photodetector readout to improve the sensitivity of positron emission tomography

Readout Strategies and Asynchronous Architectures

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