TOF-PET image reconstruction with multiple timing kernels applied on Cherenkov radiation in BGO

Efthimiou, Nikos; Kratochwil, N.; Gundacker, S.; Polesel, Andea; Salomoni, Matteo; Auffray, E.; Pizzichemi, Marco

doi:10.36227/techrxiv.13108238.v1

Cited by 4 publications

(7 citation statements)

References 23 publications

(31 reference statements)

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“…As described earlier, the timing resolution depends on the energy deposition and sharing, leading to a complex TOF model for the scanner. However, here, the variety of timing resolutions obtained from the different combinations of detected events is much wider than in cases investigated previously [27], [43]. Efthimiou et al [27], [43], studying Cherenkov-based detectors [44]- [48], reported that the complexity of the reconstruction with multiple (25) kernels slowed down their convergence.…”

Section: Discussionmentioning

confidence: 67%

“…However, here, the variety of timing resolutions obtained from the different combinations of detected events is much wider than in cases investigated previously [27], [43]. Efthimiou et al [27], [43], studying Cherenkov-based detectors [44]- [48], reported that the complexity of the reconstruction with multiple (25) kernels slowed down their convergence. In this work, with only three Gaussian kernels, the Contrast Recovery Coefficient (CRC) converged slightly faster than the single and slower TOF kernel used for the BGO.…”

Section: Discussionmentioning

confidence: 67%

“…The coincidence window was set to 4 ns and the GATE parameter minSectorDifference to 88 [32]. In previous work on TOF PET reconstruction applied on Cherenkov radiation in BGO [27], energy resolution of 19% was measured, whereas, for the heterostructured scintillators, worse resolution can be expected due to the layered structure. Here, to isolate the effects of CTR on the reconstruction of TOF PET image reconstruction, the same energy resolution 20% and an energy window of 400 − 650 keV were used in all models.…”

Section: B Monte Carlo Simulationsmentioning

confidence: 99%

“…Predicting the impact of the volume fraction and the sampling frequency (number of layers) is not trivial, and we used Monte Carlo simulations for two example BGO/plastic heterostructured scintillators to that end. In addition, in the image reconstruction, we exploited the fraction of events with a faster CTR by applying different timing kernels [27]. We compare the performance of a heterostructure-based scanner to one with bulk BGO detectors in terms of count rates and the quality of the reconstructed images in terms of contrast recovery (CRC) and contrast to noise ratio (CNR) using the NEMA IQ phantom.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Image Reconstruction Analysis for Positron Emission Tomography with Heterostructured Scintillators

Mohr¹,

Efthimiou²,

Pagano³

et al. 2022

Preprint

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<p>The concept of structure engineering has been proposed for the exploration of the next generation of radiation detectors with improved performance. A Time Of Flight Positron Emission Tomography (TOF-PET) scanner with heterostructured scintillators with a pixel size of 3.0×3.1×15 mm<sup>3</sup> was simulated. The heterostructures consisted of alternating layers of BGO as a dense material with high stopping power and plastic as a fast light emitter. Using the GATE simulation toolkit, a detector time resolution was calculated as a function of the deposited and shared energy in both materials on an event-by-event basis. We saw that while sensitivity was reduced to 32% for 100 µm thick plastic layers and 52% for 50 µm, the CTR distribution improved to 204±49 ps and 220±41 ps respectively, compared to 276±9 ps for bulk BGO. We divided the events into three groups based on their CTR and modeled them with different Gaussian TOF kernels. On a NEMA IQ phantom, the heterostructures had better contrast recovery in early iterations, while on the other hand, BGO achieved a better Contrast-to-Noise Ratio (CNR) after the 10th - 15th iteration due to the higher sensitivity. The developed simulation and reconstruction methods constitute new tools for evaluating different detector designs with complex time responses.</p>

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Section: Discussionmentioning

confidence: 67%

Section: Discussionmentioning

confidence: 67%

Section: B Monte Carlo Simulationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Image Reconstruction Analysis for Positron Emission Tomography with Heterostructured Scintillators

Mohr¹,

Efthimiou²,

Pagano³

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

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“…For best image quality, a double Gaussian TOF kernel -as opposed to the conventional single Gaussian -had to be used because the time difference of the detected events in the Cherenkov detectors has long tails (Figure 10). A recent study has also successfully implemented a double Gaussian TOF kernel for BGO detectors while also exploring Gaussian mixture models [47]. In this study, the photo-detectors were modeled to be of negligible size, meaning that the detector with readouts at the sides (2-sided-top-bottom, 6-sided) had basically the same size compared to the detector with the readout at the back of the crystal.…”

Section: Discussionmentioning

confidence: 99%

Exploring the Potential of a Cherenkov TOF PET Scanner: A Simulation Study

Razdevsek

Pestotnik²,

Križan

et al. 2023

IEEE Trans. Radiat. Plasma Med. Sci.

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The detection of annihilation photons in PET is based on scintillation light detection, but an interesting alternative is detection based on Cherenkov photons. Dense Cherenkov radiators provide an opportunity for high gamma detection efficiency -due to their high stopping power and photofraction -and excellent coincidence time resolution (CTR). However, because only a few tens of Cherenkov photons follow a gamma interaction in the radiator, the detection efficiency and the energy resolution of a pure Cherenkov detector are an issue. This work explores gamma detection efficiency and CTR of PbF2 based detectors with different surface treatments and photo-detectors covering one, two, or all crystal faces. Following the detector simulation analysis, we investigate the potential performance of a full-size Cherenkov PET scanner and quantitatively compare image quality with a commercial clinical PET scanner. We demonstrate that even though pure Cherenkov scanners have basically no energy resolution, the scatter fraction of around 50% is not prohibitively large, and images comparable to the stateof-the-art clinical PET scanner can be achieved due to improved efficiency and CTR attainable with PbF2.

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The SNR of Positron Emission Data With Gaussian and Non-Gaussian Time-of-Flight Kernels, With Application to Prompt Photon Coincidence

Nuyts

Defrise

Gundacker

et al. 2023

IEEE Trans. Med. Imaging

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It is well known that measurement of the time-of-flight (TOF) increases the information provided by coincident events in positron emission tomography (PET). This information increase propagates through the reconstruction and improves the signal-to-noise ratio in the reconstructed images. Takehiro Tomitani has analytically computed the gain in variance in the reconstructed image, provided by a particular TOF resolution, for the center of a uniform disk and for a Gaussian TOF kernel. In this paper we extend this result, by computing the signal-to-noise ratio (SNR) contributed by individual coincidence events for two different tasks. One task is the detection of a hot spot in the center of a uniform cylinder. The second one is the same as that considered by Tomitani, i.e. the reconstruction of the central voxel in the image of a uniform cylinder. In addition, we extend the computation to non-Gaussian TOF kernels. It is found that a modification of the TOF-kernel changes the SNR for both tasks in almost exactly the same way. The proposed method can be used to compare TOF-systems with different and possibly event-dependent TOF-kernels, as encountered when prompt photons, such as Cherenkov photons are present, or when the detector is composed of different scintillators. The method is validated with simple 2D simulations and illustrated by applying it to PET detectors producing optical photons with event-dependent timing characteristics.

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TOF-PET image reconstruction with multiple timing kernels applied on Cherenkov radiation in BGO

Cited by 4 publications

References 23 publications

Image Reconstruction Analysis for Positron Emission Tomography with Heterostructured Scintillators

Image Reconstruction Analysis for Positron Emission Tomography with Heterostructured Scintillators

Exploring the Potential of a Cherenkov TOF PET Scanner: A Simulation Study

The SNR of Positron Emission Data With Gaussian and Non-Gaussian Time-of-Flight Kernels, With Application to Prompt Photon Coincidence

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