Systematic study on factors influencing the performance of interdetector scatter recovery in small‐animal <scp>PET</scp>

Lee, Seung‐Eun; Lee, Min Sun; Kim, Kyeong Yun; Lee, Jae Sung

doi:10.1002/mp.13020

Cited by 6 publications

(3 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We estimated the increment of sensitivity by adding IDS events to practical double coincidences in the brain-sized PET. When using the same LSO crystals, IDS was less frequently detected in brain PET than small-animal PET which was tested in the previous study (Lee et al 2018b). In the brain PET geometry, the sectors were placed far from each other, and both the block size and the gaps between the blocks were relatively large compared to the compact small-animal PET.…”

Section: Discussionmentioning

confidence: 88%

See 1 more Smart Citation

Recovery of inter-detector and inter-crystal scattering in brain PET based on LSO and GAGG crystals

et al. 2020

Self Cite

View full text Add to dashboard Cite

Gadolinium aluminum gallium garnet (GAGG) is a promising scintillator crystal for positron emission tomography (PET) detectors owing to its advantages of energy resolution, light yield, and absence of intrinsic radiation. However, a large portion of the incident photons undergoes Compton scattering within GAGG crystal because of its low stopping power compared to that of lutetium-based crystals such as Lu2SiO5 (LSO). Inter-detector scattering (IDS) and inter-crystal scattering (ICS) result in loss of sensitivity and image quality of PET, respectively. We performed a Monte Carlo simulation study to evaluate IDS recovery in our currently developing brain-dedicated PET, and extended the idea to ICS recovery. We also compared the impact of the recoveries on LSO- and GAGG-based PET scanners. We measured the sensitivity and spatial resolution of the brain PET, and analyzed the image quality using a lesion phantom, a hot-rod phantom, and a 2D Hoffman phantom with applying IDS or ICS recovery. IDS recovery increased the PET sensitivity and improved the noise level of the reconstructed images. ICS recovery enhanced the spatial resolution and the contrast of the images was improved. As the occurrence rates of IDS and ICS were higher in GAGG than in LSO, the overall impact of IDS or ICS recovery was significant in GAGG. In conclusion, we showed that the proportional method would be suitable for IDS and ICS recoveries of PET, and emphasized the importance of ICS and IDS recoveries for PET using crystals with low stopping power.

show abstract

Section: Discussionmentioning

confidence: 88%

“…In our previous work, we evaluated several IDS recovery methods in a small-animal PET (Lee et al 2018b). The proportional method (Lage et al 2015), which is explained in section 2.2.1, yielded a good signal-to-noise ratio and contrast of the reconstructed images compared to those of other methods.…”

Section: Lso Gaggmentioning

confidence: 99%

Recovery of inter-detector and inter-crystal scattering in brain PET based on LSO and GAGG crystals

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…The degree of improvement in volumetric resolution was relatively small for the radial resolutions of the peripheral region where the parallax error was dominant over ICS blurring because of the absence of depth-ofinteraction (DOI) measurement. DOI capability can improve recovery accuracy by providing additional information on the interaction position (Lee et al 2018). Combining DOI information and ICS recovery for real PET detectors remains as a future study.…”

Section: Discussionmentioning

confidence: 98%

Experimental evaluation of convolutional neural network-based inter-crystal scattering recovery for high-resolution PET detectors

Lee

2023

Phys. Med. Biol.

Self Cite

View full text Add to dashboard Cite

Objective: One major limiting factor for achieving high resolution of positron emission tomography (PET) is a Compton scattering of the photon within the crystal, also known as inter-crystal scattering (ICS). We proposed and evaluated a convolutional neural network (CNN) named ICS-Net to recover ICS in light-sharing detectors for real implementations preceded by simulations. ICS-Net was designed to estimate the first-interacted row or column individually from the 8×8 photosensor amplitudes.Approach: We tested 8×8, 12×12, and 21×21 Lu2SiO5 arrays with pitches of 3.2, 2.1, and 1.2 mm, respectively. We first performed simulations to measure the accuracies and error distances, comparing the results to previously studied pencil-beam-based CNN to investigate the rationality of implementing fan-beam-based ICS-Net. For experimental implementation, the training dataset was prepared by obtaining coincidences between the targeted row or column of the detector and a slab crystal on a reference detector. ICS-Net was applied to the detector pair measurements with moving a point source from the edge to center using automated stage to evaluate their intrinsic resolutions. We finally assessed the spatial resolution of the PET ring.Main results: The simulation results showed that ICS-Net improved the accuracy compared with the case without recovery, reducing the error distance. ICS-Net outperformed a pencil-beam CNN, which provided a rationale to implement a simplified fan-beam irradiation. With the experimentally trained ICS-Net, the degree of improvements in intrinsic resolutions were 20%, 31%, and 62% for the 8×8, 12×12, and 21×21 arrays, respectively. The impact was also shown in the ring acquisitions, achieving improvements of 11–46%, 33–50%, and 47–64% (values differed from the radial offset) in volume resolutions of 8×8, 12×12, and 21×21 arrays, respectively.Significance: The experimental results demonstrate that ICS-Net can effectively improve the image quality of high-resolution PET using a small crystal pitch, requiring a simplified setup for training dataset acquisition.

show abstract

Strategies for mitigating inter-crystal scattering effects in positron emission tomography: a comprehensive review

Lee,

Shim,

Lee

2024

Biomed. Eng. Lett.

View full text Add to dashboard Cite

Inter-crystal scattering (ICS) events in Positron Emission Tomography (PET) present challenges affecting system sensitivity and image quality. Understanding the physics and factors influencing ICS occurrence is crucial for developing strategies to mitigate its impact. This review paper explores the physics behind ICS events and their occurrence within PET detectors. Various methodologies, including energy-based comparisons, Compton kinematics-based approaches, statistical methods, and Artificial Intelligence (AI) techniques, which have been proposed for identifying and recovering ICS events accurately are introduced. Energy-based methods offer simplicity by comparing energy depositions in crystals. Compton kinematics-based approaches utilize trajectory information for first interaction position estimation, yielding reasonably good results. Additionally, statistical approach and AI algorithms contribute by optimizing likelihood analysis and neural network models for improved positioning accuracy. Experimental validations and simulation studies highlight the potential of recovering ICS events and enhancing PET sensitivity and image quality. Especially, AI technologies offers a promising avenue for addressing ICS challenges and improving PET image accuracy and resolution. These methods offer promising solutions for overcoming the challenges posed by ICS events and enhancing the accuracy and resolution of PET imaging, ultimately improving diagnostic capabilities and patient outcomes. Further studies applying these approaches to real PET systems are needed to validate theoretical results and assess practical implementation feasibility.

show abstract

Systematic study on factors influencing the performance of interdetector scatter recovery in small‐animal PET

Cited by 6 publications

References 37 publications

Recovery of inter-detector and inter-crystal scattering in brain PET based on LSO and GAGG crystals

Recovery of inter-detector and inter-crystal scattering in brain PET based on LSO and GAGG crystals

Experimental evaluation of convolutional neural network-based inter-crystal scattering recovery for high-resolution PET detectors

Strategies for mitigating inter-crystal scattering effects in positron emission tomography: a comprehensive review

Contact Info

Product

Resources

About