Estimation of Crystal Timing Properties and Efficiencies for the Improvement of (Joint) Maximum-Likelihood Reconstructions in TOF-PET

Rezaei, Ahmadreza; Schramm, Georg; Laere, Koen Van

doi:10.1109/tmi.2019.2938028

Cited by 13 publications

(7 citation statements)

References 28 publications

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“…Moreover, shorter imaging time can greatly accelerate the examination time and reduce the pain of patients [ 4 ]. The performance of a PET system [ 5 , 6 , 7 , 8 , 9 ] directly depends on its components, which include a scintillation crystal, a photodetector, a readout circuit, etc.…”

Section: Introductionmentioning

confidence: 99%

Design and Evaluation of LYSO/SiPM LIGHTENING PET Detector with DTI Sampling Method

Deng

Chen

2020

Sensors

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Positron emission tomography (PET) has a wide range of applications in the treatment and prevention of major diseases owing to its high sensitivity and excellent resolution. However, there is still much room for optimization in the readout circuit and fast pulse sampling to further improve the performance of the PET scanner. In this work, a LIGHTENING® PET detector using a 13 × 13 lutetium-yttrium oxyorthosilicate (LYSO) crystal array read out by a 6 × 6 silicon photomultiplier (SiPM) array was developed. A novel sampling method, referred to as the dual time interval (DTI) method, is therefore proposed to realize digital acquisition of fast scintillation pulse. A semi-cut light guide was designed, which greatly improves the resolution of the edge region of the crystal array. The obtained flood histogram shown that all the 13 × 13 crystal pixels can be clearly discriminated. The optimum operating conditions for the detector were obtained by comparing the flood histogram quality under different experimental conditions. An average energy resolution (FWHM) of 14.3% and coincidence timing resolution (FWHM) of 972 ps were measured. The experimental results demonstrated that the LIGHTENING® PET detector achieves extremely high resolution which is suitable for the development of a high performance time-of-flight PET scanner.

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Section: Introductionmentioning

confidence: 99%

Design and Evaluation of LYSO/SiPM LIGHTENING PET Detector with DTI Sampling Method

Deng

Chen

2020

Sensors

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“…With improvements in the TOF resolution of future scanners, accurate TOF-based calibrations will become increasingly important. It has been shown that compared to conventional MLEM reconstructions, joint estimation techniques are more sensitive to timing calibration errors (timing offsets and time resolution (Rezaei et al 2019)).…”

Section: Image Reconstruction and Joint Estimationmentioning

confidence: 99%

Quantitative PET in the 2020s: a roadmap

et al. 2021

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Positron emission tomography (PET) plays an increasingly important role in research and clinical applications, catalysed by remarkable technical advances and a growing appreciation of the need for reliable, sensitive biomarkers of human function in health and disease. Over the last 30 years a large amount of the physics and engineering effort in PET has been motivated by the dominant clinical application during that period, oncology. This has led to important developments such as PET/CT, whole-body PET, 3D PET, accelerated statistical image reconstruction, and time-of-flight PET. Despite impressive improvements in image quality as a result of these advances, the emphasis on static, semiquantitative "hot spot" imaging for oncologic applications has meant that the capability of PET for quantifying biologically relevant parameters based on tracer kinetics has not been fully exploited. More recent advances, such as PET/MR and total body PET, have opened up the ability to address a vast range of new research questions from which a future expansion of applications and radiotracers appears highly likely. Many of these new applications and tracers will, at least initially, require quantitative analyses that more fully exploit the exquisite sensitivity of PET and the tracer principle on which it is based. It is also expected that they will require more sophisticated quantitative analysis methods than those that are currently available. At the same time, artificial intelligence is revolutionizing data analysis and impacting the relationship between the statistical quality of the acquired data and the information we can extract from the data. In this roadmap, leaders of the key sub-disciplines of the field identify the challenges and opportunities to be addressed over the next 10 years that will enable PET to realise its full quantitative potential, initially in research laboratories and, ultimately, in clinical practice.

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“…This underlines that precise knowledge of the TOF kernels is crucial for accurate TOF-MLEM reconstructions. Fortunately, data-driven ML techniques can be used to estimate a global TOF kernel width [139] or even an LOR-dependent correction factor for the TOF kernel width [140] in case the TOF resolution is LORdependent.…”

Section: A Tof-pet Reconstruction Basicsmentioning

confidence: 99%

“…Recently, deep learning techniques (e.g., convolutional neural networks) have been used to improve the quality of the attenuation images obtained from MLAA [ 157 ], [ 158 ]. Also, it was recently shown [ 139 ] that joint estimation of activity and attenuation is more sensitive to inaccuracies in the TOF kernel, such as the exact TOF resolution and possible coincidence timing offsets, indicating that the required precision in the TOF calibration and modeling needs to be improved for future systems with even better TOF resolution.…”

Section: Utilization Of Time Resolution In Pet Image Reconstructionmentioning

confidence: 99%

Time of Flight in Perspective: Instrumental and Computational Aspects of Time Resolution in Positron Emission Tomography

Schaart

Schramm

Surti

2021

IEEE Trans. Radiat. Plasma Med. Sci.

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The first time-of-flight positron emission tomography (TOF-PET) scanners were developed as early as in the 1980s. However, the poor light output and low detection efficiency of TOF-capable detectors available at the time limited any gain in image quality achieved with these TOF-PET scanners over the traditional non-TOF PET scanners. The discovery of LSO and other Lu-based scintillators revived interest in TOF-PET and led to the development of a second generation of scanners with high sensitivity and spatial resolution in the mid-2000s. The introduction of the silicon photomultiplier (SiPM) has recently yielded a third generation of TOF-PET systems with unprecedented imaging performance. Parallel to these instrumentation developments, much progress has been made in the development of image reconstruction algorithms that better utilize the additional information provided by TOF. Overall, the benefits range from a reduction in image variance (SNR increase), through allowing joint estimation of activity and attenuation, to better reconstructing data from limited angle systems. In this work, we review these developments, focusing on three broad areas: (1) timing theory and factors affecting the time resolution of a TOF-PET system, (2) utilization of TOF information for improved image reconstruction, and (3) quantification of the benefits of TOF compared to non-TOF PET. Finally, we offer a brief outlook on the TOF-PET developments anticipated in the short and longer term. Throughout this work, we aim to maintain a clinically-driven perspective, treating TOF as one of multiple (and sometimes competitive) factors that can aid in the optimization of PET imaging performance.

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Estimation of Crystal Timing Properties and Efficiencies for the Improvement of (Joint) Maximum-Likelihood Reconstructions in TOF-PET

Cited by 13 publications

References 28 publications

Design and Evaluation of LYSO/SiPM LIGHTENING PET Detector with DTI Sampling Method

Design and Evaluation of LYSO/SiPM LIGHTENING PET Detector with DTI Sampling Method

Quantitative PET in the 2020s: a roadmap

Time of Flight in Perspective: Instrumental and Computational Aspects of Time Resolution in Positron Emission Tomography

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