Monte Carlo Optical Simulations of a Small FoV Gamma Camera. Effect of Scintillator Thicknesses and Septa Materials

Ricci, Rita; Κωστού, Θεοδώρα; Chatzipapas, Konstantinos; Fysikopoulos, Eleftherios; Loudos, George; Montalto, Luigi; Scalise, Lorenzo; Rinaldi, D.; Stoppa, David

doi:10.3390/cryst9080398

Cited by 8 publications

(7 citation statements)

References 29 publications

(42 reference statements)

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“…Modeled physics processes include photoelectric, Compton and Rayleigh scattering for gamma rays, as well as ionization, Bremsstrahlung, and multiple-scattering for electrons. Moreover, a reference energy resolution of 9% (typical energy resolution of conventional NaI detectors) was considered in GATE simulation [41][42][43]. In addition, the intrinsic spatial resolution of the scanner (a typical value of 3.2 mm) was also considered during MC simulations.…”

Section: Monte Carlo Simulationmentioning

confidence: 99%

Design and optimization of a breast-dedicated SPECT scanner with multi-lofthole collimation

Saed¹,

Sadremomtaz²,

Mahani³

2022

J. Inst.

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Background: the need for simultaneous high-sensitivity and high-resolution breast SPECT imaging mandates to design and optimize dedicated scanners. Therefore, this work aims to design and optimize a novel breast-dedicated SPECT system with multi-lofthole collimator. Materials and Methods: in this research, a novel breast-dedicated scanner is designed and then optimized. The scanner is equipped with a single full-ring multi-lofthole collimation long with modular NaI(Tl) detectors. The step-and-shoot data acquisition was considered with two steps. Then, an analytic optimization was conducted to balance the existing sensitivity-resolution tradeoff. To do so, several scanner geometries were investigated. The optimal configuration maximized the system sensitivity at a given system resolution. Furthermore, the scanner was also modeled within the GATE simulator. Then, detector energy resolution, septal penetration and scattering, and system sensitivity were calculated. Analytic findings were also compared with the simulated ones. Results: the results showed that high sensitivity of about 2 cps/kBq can be obtained for a diameter of lofthole 3.05 mm with a 75° opening angle. Results of GATE simulations showed clinically acceptable performance of the system offering 9% energy resolution for a point source. The septal penetration and scattering were approximately 0.5% and 0.2%, respectively, for cylindrical water phantom and tungsten as collimator material. Conclusion: the designed SPECT scanner provides promising results in terms of sensitivity and spatial resolution and therefore outperforms the traditional multi-pinhole collimation by a much higher sensitivity at a given system resolution.

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Section: Monte Carlo Simulationmentioning

confidence: 99%

Design and optimization of a breast-dedicated SPECT scanner with multi-lofthole collimation

Saed¹,

Sadremomtaz²,

Mahani³

2022

J. Inst.

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“…In addition to detector development, Monte Carlo simulations are widely used to simulate complete clinical and preclinical imaging systems (Ricci et al 2019, Ahmed et al 2020, Sarrut et al 2021a, Sanaat et al 2022, Zaidi and Andreo 2022. Detailed and complete system optical simulations of these systems, often composed of hundreds or thousands of scintillators, are computationally prohibitive and thus are always limited to the analysis of the first interaction gamma points to study the system performance (Gu et al 2015, Abbaszadeh et al 2018, Borghi et al 2018, Surti and Karp 2018.…”

Section: Introductionmentioning

confidence: 99%

A generative adversarial network to speed up optical Monte Carlo simulations

Trigila

Srikanth

Roncali

2023

Mach. Learn.: Sci. Technol.

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Detailed simulation of optical photon transport and detection in radiation detectors is often used for crystal-based gamma detector optimization. However, the time and memory burden associated with the track-wise approach to particle transport and detection in commonly used Monte Carlo codes makes optical simulation prohibitive at a system level, where hundreds to thousands of scintillators must be modeled. Consequently, current large system simulations do not include detailed detector models to analyze the potential performance gain with new radiation detector technologies. Generative Adversarial Networks are explored as a tool to speed up the optical simulation of crystal-based detectors. These networks learn training datasets made of high-dimensional data distributions. Once trained, the resulting model can produce distributions belonging to the training data probability distribution. In this work, we present the proof of concept of using a Generative Adversarial Network to enable high-fidelity optical simulations of nuclear medicine systems, mitigating their computational complexity. The architecture of the first network version and high-fidelity training dataset is discussed. The latter is generated through accurate optical simulation with GATE/Geant4, and contains the position, direction, and energy distributions of the optical photons emitted by 511 keV gamma rays in bismuth germanate and detected on the photodetector face. We compare the GAN and simulation-generated distributions in terms of similarity using the Jensen-Shannon distance. Excellent agreement was found with similarity values higher than 93.5% for all distributions. Moreover, the GAN speeded the optical photon distribution generation by up to 2 orders of magnitude. These very promising results have the potential to drastically change the use of nuclear imaging system optical simulations by enabling high-fidelity system-level simulations in reasonable computation times. The ultimate is to integrate the GAN within GATE/Geant4 since numerous applications (large detectors, bright scintillators, Cerenkov-based timing positron emission tomography) can benefit from these improvements.

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“…Gate is a piece of Monte Carlo simulation software popular in the field of nuclear medical imaging [ 17 , 18 ]. Users can easily simulate physical processes associated with high-energy particles and rays since GATE provides various PET and SPECT system standard models.…”

Section: Introductionmentioning

confidence: 99%

“…This greatly influences the sensitivity of the gamma camera. To overcome these issues, different types of collimators are used to improve the field of view (FOV) and accuracy of the gamma camera [ 7 , 18 , 23 ]. These include parallel holes, holes, and converging and diverging collimators.…”

Section: Introductionmentioning

confidence: 99%

A Novel Portable Gamma Radiation Sensor Based on a Monolithic Lutetium-Yttrium Oxyorthosilicate Ring

Zhang

Xie

et al. 2021

Sensors

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Portable radiation detectors are widely used in environmental radiation detection and medical imaging due to their portability feature, high detection efficiency, and large field of view. Lutetium-yttrium oxyorthosilicate (LYSO) is a widely used scintillator in gamma radiation detection. However, the structure and the arrangement of scintillators limit the sensitivity and detection accuracy of these radiation detectors. In this study, a novel portable sensor based on a monolithic LYSO ring was developed for the detection of environmental radiation through simulation, followed by construction and assessments. Monte Carlo simulations were utilized to prove the detection of gamma rays at 511 keV by the developed sensor. The simulations data, including energy resolutions, decoding errors, and sensitivity, showed good potential for the detection of gamma rays by the as-obtained sensor. The experimental results using the VA method revealed decoding errors in the energy window width of 50 keV less than 2°. The average error was estimated at 0.67°, a sufficient value for the detection of gamma radiation. In sum, the proposed radiation sensor appears promising for the construction of high-performance radiation detectors and systems.

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Monte Carlo Optical Simulations of a Small FoV Gamma Camera. Effect of Scintillator Thicknesses and Septa Materials

Cited by 8 publications

References 29 publications

Design and optimization of a breast-dedicated SPECT scanner with multi-lofthole collimation

Design and optimization of a breast-dedicated SPECT scanner with multi-lofthole collimation

A generative adversarial network to speed up optical Monte Carlo simulations

A Novel Portable Gamma Radiation Sensor Based on a Monolithic Lutetium-Yttrium Oxyorthosilicate Ring

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