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In this article, we investigate quantum entanglement (QE) filtering to address the challenges in multi-isotope positron emission tomography (PET) or in PET studies utilizing radiotracers with dual- positron and prompt gamma emissions. Via GATE simulation, we demonstrate the efficacy of QE filtering using a one-of-a-kind cadmium zinc telluride (CZT) PET system - establishing its viability as a multimodal scanner and ability to perform QE filtering. We show the high Compton scattering probability in this CZT-based scanner with 44.2% of gammas undergoing a single scatter prior to absorption. Additionally, the overall system sensitivity as a standard PET scanner (11.29%), QE-PET scanner (6.81%), and Compton Camera (11.29%) is quantified. Further, we find a 23% decrease in the double Compton scatter (DCSc) frequency needed for QE filtering for each mm decrease in crystal resolution and an increase in mean absolute error (MAE) of their Δϕs from 6.8° for 1 mm resolution to 9.5° , 12.2° , and 15.3° for 2, 4, and 8 mm resolution, respectively. These results reinforce the potential of CZT detectors to lead next generation PET systems taking full advantage of the QE information of positron annihilation photons.

Purpose: Clinical trials have yielded promising results for 177Lutetium Prostate Specific Membrane Antigen (177Lu-PSMA) therapy in metastatic castration resistant prostate cancer (mCRPC) patients. However, the development of precise methods for internal dosimetry and accurate dose estimation has been considered ongoing research. This study aimed to calculate the absorbed dose to the critical organs and metastasis regions using GATE 9.0 Monte Carlo simulation (MCS) as a gold standard to compare the OLINDA 1.1 and IDAC 2.1 software. Material and Methods: This study investigated absorbed doses to different organs in 9 mCRPC patients during their first treatment cycle. Whole-body planar images were acquired at 1 ± 0.5, 4 ± 0.5, 24 ± 2, 48 ± 2, 72 ± 2, and 144 ± 2 h post-injection, with SPECT/CT images obtained at 24 ± 2 h. Absorbed doses were calculated for five organs and the entire metastasis regions using GATE, OLINDA, and IDAC platforms. The spherical method was used to determine and compare the absorbed doses in metastatic regions and undefined organs in OLINDA and IDAC Phantom. Results: The organ-absorbed dose calculations produced by GATE were consistent with those obtained from OLINDA and IDAC. The average percentage differences in absorbed dose for all organs between Monte Carlo calculations and the estimated from IDAC and OLINDA were -0.24 ± 2.14% and 5.16 ± 5.66%, respectively. There was a significant difference between GATE and both IDAC (17.55 ± 29.1%) and OLINDA (25.86 ± 18.04%) in determining absorbed doses to metastatic areas using the spherical model. Conclusion: The absorbed dose of organs in the first treatment cycle remained below tolerable limits. However, cumulative absorbed doses should be considered for the administered activities in the next cycles of treatment. While Monte Carlo, IDAC, and OLINDA results were aligned for organ dose calculations, patient-specific dosimetry may be necessary due to anatomical and functional changes. Accurate dose estimation for undefined organs and metastatic regions using the spherical model is significantly influenced by tissue density, highlighting the value of CT imaging. [ABSTRACT FROM AUTHOR]

Copyright of Metal Working (1674-165X) is the property of Metal Working Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

There has been a strong interest in using neural networks to solve several tasks in PET medical imaging. One of the main problems faced when using neural networks is the quality, quantity, and availability of data to train the algorithms. In order to address this issue, we have developed a pipeline that enables the generation of voxelized synthetic PET phantoms, simulates the acquisition of a PET scan, and reconstructs the image from the simulated data. In order to achieve these results, several pieces of software are used in the different steps of the pipeline. This pipeline solves the problem of generating diverse PET datasets and images of high quality for different types of phantoms and configurations. The data obtained from this pipeline can be used to train convolutional neural networks for PET reconstruction. [ABSTRACT FROM AUTHOR]

This work aimed to determine the linear and mass attenuation coefficients of soy-lignin bonded Rhizophora spp. particleboard intended for use as a phantom material using Monte Carlo GATE simulation. At a desired density of 1.0 g · cm-3, particleboard constructed of Rhizophora spp. wood trunk bonded with soy flour and lignin was created. The sample's elemental composition was identified using energy dispersive X-ray spectroscopy. The GATE software was used to simulate the setup with the histories of 1 x 107, and comparison was made between the experimental and simulation data. The disparities between the linear and mass attenuation coefficients of the samples experimentally measured and calculated using GATE at low energy photons were quite small. The result revealed a good agreement between the experimental and simulation data, and the attenuation coefficients were in close proximity with XCOM of water. The outcome revealed GATE adequacy for validation of attenuation coefficient measurement in bioresources phantom material for medical physics application. [ABSTRACT FROM AUTHOR]

Background: Radiobiological effectiveness of radiation in cancer treatment can be studied at different scales (molecular till organ scale) and different time post irradiation. The production of free radicals and reactive oxygen species during water radiolysis is particularly relevant to understand the fundamental mechanisms playing a role in observed biological outcomes. The development and validation of Monte Carlo tools integrating the simulation of physical, physico‐chemical and chemical stages after radiation is very important to maintain with experiments. Purpose: Therefore, in this study, we propose to validate a new Geant4‐DNA chemistry module through the simulation of water radiolysis and Fricke dosimetry experiments on a proton preclinical beam line. Material and methods: In this study, we used the GATE Monte Carlo simulation platform (version 9.3) to simulate a 67.5 MeV proton beam produced with the ARRONAX isochronous cyclotron (IBA Cyclone 70XP) at conventional dose rate (0.2 Gy/s) to simulate the irradiation of ultra‐pure liquid water samples and Fricke dosimeter. We compared the depth dose profile with measurements performed with a plane parallel Advanced PTW 34045 Markus ionization chamber. Then, a new Geant4‐DNA chemistry application proposed from Geant4 version 11.2 has been used to assess the evolution of HO•${\mathrm{HO}}^ \bullet $, eaq−${\mathrm{e}}_{{\mathrm{aq}}}^ - $, H3O+${{\mathrm{H}}}_3{{\mathrm{O}}}^ + $, H2O2${{\mathrm{H}}}_2{{\mathrm{O}}}_2$, H2${{\mathrm{H}}}_2$, HO2•${\mathrm{HO}}_2^ \bullet $, HO2−,O2•−${\mathrm{HO}}_2^ - ,{\mathrm{\ O}}_2^{ \bullet - }$ and HO−${\mathrm{HO}}^ - $ reactive species along time until 1‐h post‐irradiation. In particular, the effect of oxygen and pH has been investigated through comparisons with experimental measurements of radiolytic yields for H2O2${{\mathrm{H}}}_2{{\mathrm{O}}}_2$ and Fe3+. Results: GATE simulations reproduced, within 4%, the depth dose profile in liquid water. With Geant4‐DNA, we were able to reproduce experimental H2O2${{\mathrm{H}}}_2{{\mathrm{O}}}_2$ radiolytic yields 1‐h post‐irradiation in aerated and deaerated conditions, showing the impact of small changes in oxygen concentrations on species evolution along time. For the Fricke dosimeter, simulated G(Fe3+) is 15.97 ± 0.2 molecules/100 eV which is 11% higher than the measured value (14.4 ± 04 molecules/100 eV). Conclusions: These results aim to be consolidated by new comparisons involving other radiolytic species, such as eaq−${\mathrm{e}}_{{\mathrm{aq}}}^ - $ or ,O2•−$,{\mathrm{\ O}}_2^{ \bullet - }$ to further study the mechanisms underlying the FLASH effect observed at ultra‐high dose rates (UHDR). [ABSTRACT FROM AUTHOR]

Spinal osteoarthritis, a degenerative condition of the spine, significantly impairs quality of life, causing pain, stiffness, and limited mobility. Treatment primarily aims to improve functionality and quality of life. This study investigated the effects of lower back surgery (e.g., spinal decompression with vertebra stabilization) on upper-limb maximum strength, lower limb functionality, and quality of life in osteoarthritis patients. A total of 16 patients (♀ = 10 and ♂ = 6) patients from the orthopedic clinic who were diagnosed with osteoarthritis based on MRI and clinical symptoms underwent the surgery. Their handgrip strength, lower limb functionality (6 min walk test), and quality of life (Flanagan quality of life scale) were assessed before and after the surgery. A repeated measures ANOVA was conducted to assess differences in these metrics pre- and post-surgery across the entire patient cohort, as well as within gender-specific subgroups. A large positive effect was seen in the 6 min walk (p = 0.02, d = −0.83) test but not in the handgrip test or quality of life. However, female patients showed a trend towards better quality of life. The results of this study provide evidence for the effectiveness of surgery in the treatment of spinal osteoarthritis and underscore the need for personalized treatment approaches in the treatment of spinal osteoarthritis. [ABSTRACT FROM AUTHOR]

In time-of-flight positron emission tomography (TOF-PET), a coincidence time resolution (CTR) below 100 ps reduces the angular coverage requirements and, thus, the geometric constraints of the scanner design. Among other possibilities, this opens the possibility of using flat-panel PET detectors. Such a design would be more cost-accessible and compact and allow for a higher degree of modularity than a conventional ring scanner. However, achieving adequate CTR is a considerable challenge and requires improvements at every level of detection. Based on recent results in the ongoing development of optimised TOF-PET photodetectors and electronics, we expect that within a few years, a CTR of about 75 ps will be be achievable at the system level. In this work, flat-panel scanners with four panels and various design parameters were simulated, assessed and compared to a reference scanner based on the Siemens Biograph Vision using NEMA NU 2-2018 metrics. Point sources were also simulated, and a method for evaluating spatial resolution that is more appropriate for flat-panel geometry is presented. We also studied the effects of crystal readout strategies, comparing single-crystal and module readout levels. The results demonstrate that with a CTR below 100 ps, a flat-panel scanner can achieve image quality comparable to that of a reference clinical scanner, with considerable savings in scintillator material. [ABSTRACT FROM AUTHOR]

The analysis of environmental impacts throughout the entire process of coal-fired power plants is imperative to implement effective measures for controlling and reducing pollutant emissions. However, there is still limited research focusing on the cradle-to-gate stage in the life cycle of coal-fired power plants and their environmental impact. This study employs a life cycle assessment (LCA) methodology to assess the environmental impacts of coal-fired power plants in South Sumatra. The primary environmental impact categories of primary emissions include CO2, SO2, NOx, and CH4. The most significant environmental impacts arise from CO2 emissions, notably 98.46% from land clearing and preparation and 86.74% from overburden removal and coal extraction. These stages primarily contribute to global warming throughout the cradle-to-gate process. Sulfur dioxide emissions from land clearing activities are the main contributor to acid rain, followed by overburden removal and coal extraction (96.51%) and coal stockpiling (1.48%), which also play a role. The release of NOx from land clearing and preparation, overburden removal, and coal stockpiling contributes to the potential for eutrophication. Land clearing and preparation have a significant impact on global warming during the coal mining and distribution stages. Practical measures such as enhancing emission reduction facilities and increasing pollutant emission standards for each process are necessary to promote environmentally friendly coal-fired power plants. [ABSTRACT FROM AUTHOR]

The primary energy source in developing countries, including Indonesia, is fossil energy. Therefore, evaluating the environmental impact of coal-fired steam power plants is crucial, but limited. Comprehensive scientific analysis is required to develop appropriate alternative measures. This research aims to analyze the life cycle impact of the coal power plant at the gate, including the coal yard, coal crusher, boiler, turbine, and generator, with the functional unit of 1 kWh of electricity produced. This research provides clear recommendations for mitigating emissions from the main contributing units. The analysis reveals the highest impact in the climate change potential category (1.40 × 10-1 kg CO2 eq/kWh), while the smallest impact was recorded in the Eutrophication potential category (7.55 × 10-4 kg PO4 eq/kWh), with no impact on ozone depletion in the stratosphere. The operation of boiler and generator units (gate hotspots) are the main contributors to climate change impacts, including carbon dioxide (9.25 × 10-2 kg CO2), sulfur dioxide (8.21 × 10-3 kg SO2), and nitrogen dioxide (7.55 × 10-4 kg PO4). Alternative programs that may be implemented to reduce emissions include co-firing and installation of flue gas desulfurization and low NOx burner. The findings of this research provide guidance for developing a policy framework to promote more environmentally friendly coal power plants, thereby achieving greater energy sustainability. [ABSTRACT FROM AUTHOR]

Copyright of Water Conservancy Science & Techonlogy & Economy is the property of Water Conservancy Science & Technology & Economy Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The present investigation delves into the intricate dynamics surrounding the incorporation of thresholds and their consequential impact on parameters associated with hydraulic jumps—a phenomenon critical to the efficient functioning of the gates. In the pursuit of a comprehensive understanding, the study employed experimental models of thresholds crafted from polyethylene. These models underwent meticulous examination, encompassing variations in dimensions, widths, and positions relative to the gate. The positions explored included beneath the gate, tangent to the gate upstream, and downstream, each contributing unique insights into the behavior of water flow and energy dissipation. An intriguing outcome emerged as thresholds were introduced at different locations. The energy dissipation for a given gate opening exhibited a discernible increase, shedding light on the intricate relationship between threshold placement and hydraulic performance. Notably, as the initial depth relative to the secondary depth increased, a consequential decrease in the ∆EAB/yA was observed, signaling a convergence between the initial and secondary depths. Further illuminating the findings, a comparative analysis of energy loss was conducted across all three threshold positions—beneath the gate, tangent to the gate upstream, and downstream. This scrutiny uncovered a distinct pattern, indicating a heightened energy dissipation in scenarios where the threshold was submerged, setting it apart from conditions where the threshold was positioned otherwise. In essence, the investigation not only accentuates the intricate interplay between sluice gates, thresholds, and hydraulic parameters but also underscores the importance of considering the placement of thresholds in optimizing the energy dissipation efficiency of these hydraulic structures.

The reuse of construction materials has been a consistent practice throughout the history of architecture, especially prevalent during periods of transition when it was preferred for its ability to simplify installation and reduce construction costs. This practice was particularly common in late Roman urban contexts, where construction materials, especially ashlar and sculptural elements, were abundant following the abandonment of temples and public buildings. However, there are occasions when the use of spolia, or reused materials, goes beyond simple material recycling. The reuse and display of certain pieces carry complex implications involving symbology, cultural appropriation, or collective memory exercises that convey messages through new buildings. In this paper, we focus on the unique case of Hispanic Christian architectural sculptures that were "recycled" in new buildings during the first centuries of Islamic domination of the Iberian Peninsula, specifically within places of worship. Through a general analysis and review of some examples, we aim to reflect on the motivations and intentionality behind the use of certain sculptural pieces and their placement in new buildings, which is not arbitrary. [ABSTRACT FROM AUTHOR]

Aim: The aim of this study is to validate the dosimetric parameters of High Dose Rate 192Ir Flexi-source (mHDR v1 model) using GATE (version 9.1) Geant4-based Monte Carlo code, which is widely used in clinical applications for brachytherapy. This validation serves as a preliminary step toward investigating the issues related to tissue heterogeneities in brachytherapy dosimetry. Methods: In this study, the geometry of the 192Ir Flexi-source mHDR-v1 was simulated within a water sphere using GATE Monte Carlo code. The dosimetric parameters, including air kerma strength Sk, dose rate constant λ, radial dose function g(r), and anisotropy function F (r, θ), were computed in accordance with the TG- 43U1 and ESTRO guidelines, and the results were compared with available literature and clinical data for validation. Results: The dose rate constant obtained was 1.078 cGy h-1 U-1 ± 0.012 cGy h-1 U-1, showing a relative difference of 2.79% compared to the reference value. The radial dose function, starting from 0.25 cm to 15 cm, showed excellent agreement with a maximum of 3.43% at 15 cm. For the anisotropy function F (r, θ), the agreements were within 4.45% for 5<θ<175, and within 13.29% for all θ values. Conclusion: Results from this study demonstrate that the validation of the Flexi-source HDR192Ir source is achievable using the GATE based Monte Carlo simulation. Consequently, the GATE code can be employed to explore challenges associated with tissue heterogeneities in brachytherapy dosimetry for 192Ir Flexi-source. [ABSTRACT FROM AUTHOR]

Copyright of Pearl River is the property of Pearl River Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study investigates the critical significance of anode material selection in defining the energy spectrum and properties of X-ray photons in medical physics applications. Using the GATE platform and Monte Carlo simulations, a direct relationship between anode material atomic number and photon fluence is demonstrated. As the atomic number increases from Z = 29 (Copper) to Z = 74 (Tungsten), photon fluence rises by 62 %, indicating a substantial impact on X-ray production. Furthermore, the X-ray spectrum is affected by this material-driven changes, revealing a noticeable shift towards higher energy values: the mean energy of the continuous spectrum rises from 46.97 keV for Copper to 49.0 keV for Tungsten. The thermal properties of the material affect the temperature increase at the focal point. Rhodium and Molybdenum have a higher temperature rise than Copper (Cu) and Tungsten (W), because Cu and W have a greater thermal diffusion compared to other materials. These findings underscore the significance of anode material choice in optimizing X-ray systems which may enhance diagnostic accuracy and efficiency in diverse applications. [ABSTRACT FROM AUTHOR]

Gallium telluride thin films have emerged as a promising material for various electronic and optoelectronic applications due to their unique properties. In this study, we investigate the growth of nanometer-thick GaTe films on sapphire substrates using molecular beam epitaxy and explore the influence of the growth temperature on the structural, electronic, and optical properties of the films. X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and Raman measurements are employed to characterize the structural quality of the films, while spectroscopy ellipsometry provides insights into their electronic and optical behavior. Our findings demonstrate that a higher temperature (500 °C) is the optimized growth temperature, which significantly impacts the quality and properties of GaTe thin films, making it a critical parameter for optimizing their performance in electronic and optoelectronic devices. [ABSTRACT FROM AUTHOR]

Sluice and radial gates are common devices used to control flow in closed conduits. In high-head gated conduits, the high-velocity flow exiting the gate drags and entrains a lot of air. If the air demand of the flow is not met, the pressure drop downstream of the gate will cause structural damage or cavitation. Typically, an air vent is installed immediately downstream of the gate to supply sufficient air to the flow. In this study, the effect of the conduit gate type on the air-demand ratio was investigated. The results showed that the gate type had a very significant effect on the air-demand ratio. Significantly higher air-demand ratios were observed in the conduit with a sluice gate compared to the conduit with a radial gate. The results obtained will be useful in future modeling and design processes. [ABSTRACT FROM AUTHOR]

The present investigation delves into the intricate dynamics surrounding the incorporation of thresholds and their consequential impact on parameters associated with hydraulic jumps—a phenomenon critical to the efficient functioning of the gates. In the pursuit of a comprehensive understanding, the study employed experimental models of thresholds crafted from polyethylene. These models underwent meticulous examination, encompassing variations in dimensions, widths, and positions relative to the gate. The positions explored included beneath the gate, tangent to the gate upstream, and downstream, each contributing unique insights into the behavior of water flow and energy dissipation. An intriguing outcome emerged as thresholds were introduced at different locations. The energy dissipation for a given gate opening exhibited a discernible increase, shedding light on the intricate relationship between threshold placement and hydraulic performance. Notably, as the initial depth relative to the secondary depth increased, a consequential decrease in the ∆EAB/yA was observed, signaling a convergence between the initial and secondary depths. Further illuminating the findings, a comparative analysis of energy loss was conducted across all three threshold positions—beneath the gate, tangent to the gate upstream, and downstream. This scrutiny uncovered a distinct pattern, indicating a heightened energy dissipation in scenarios where the threshold was submerged, setting it apart from conditions where the threshold was positioned otherwise. In essence, the investigation not only accentuates the intricate interplay between sluice gates, thresholds, and hydraulic parameters but also underscores the importance of considering the placement of thresholds in optimizing the energy dissipation efficiency of these hydraulic structures. [ABSTRACT FROM AUTHOR]

In positron emission tomography (PET), the scattered photons represent a major image degrading factor. The scatter fraction (SF) of PET scanners is experimentally determined following the National Electrical Manufacturers Association (NEMA) NU 2 protocol, using a polyethylene phantom with a line source inserted at 45 mm radial offset from the phantom's center. In this work, we aim to investigate the optimal radial offset of the line source, that represents the SF of a uniformly activated phantom, for the lutetium yttrium orthosilicate (LYSO)-based uEXPLORER total body PET scanner. Additionally, we propose to study the impact of several factors (axial field-of-view (AFOV), crystal material and heterogeneities) on this optimal offset, in an effort to provide recommendations for a wide range of PET scanner configurations. We performed Monte Carlo (MC) simulations of the uEXPLORER scanner along with five phantoms of different diameters, using the Geant4 Application for Tomographic Emission (GATE) code. We performed supplemental MC simulations in which we varied the crystal material, the AFOV and we introduced bone and lung heterogeneities in the phantoms to assess their impact on the optimal offset findings. Our results demonstrated that the 45 mm offset overestimates the SF of the uniform 20 cm diameter phantom by 24.3 . Instead, an offset of 87 mm was reproducing this SF. For the phantoms having diameters in the range of 10–50 cm, an offset of 90.7 of the phantom's radius was shown to be optimal (best fit). No AFOV-related impact has been observed on this optimal offset. The influence of the heterogeneities was also small with less than 1.1 absolute deviation in the SF. This offset could then be used for all AFOV lengths PET scanners using LYSO crystal. The impact of the crystal material was shown to be minimal and an offset of 91.5 of the phantom's radius is consequently recommended as an average for other PET scanners. [ABSTRACT FROM AUTHOR]

This study compares the PRIMO and GATE Monte Carlo simulation toolkits for modeling photon beams from a TrueBeam STx Linac used in radiation therapy. Various beam configurations were evaluated against Varian's Golden Beam Data using the Gamma Index method. Both toolkits demonstrated good agreement overall, with GATE generally achieving higher gamma pass rates for percent depth dose curves than PRIMO.

Abstract Background We propose a comprehensive evaluation of a Discovery MI 4-ring (DMI) model, using a Monte Carlo simulator (GATE) and a clinical reconstruction software package (PET toolbox). The following performance characteristics were compared with actual measurements according to NEMA NU 2-2018 guidelines: system sensitivity, count losses and scatter fraction (SF), coincidence time resolution (CTR), spatial resolution (SR), and image quality (IQ). For SR and IQ tests, reconstruction of time-of-flight (TOF) simulated data was performed using the manufacturer’s reconstruction software. Results Simulated prompt, random, true, scatter and noise equivalent count rates closely matched the experimental rates with maximum relative differences of 1.6%, 5.3%, 7.8%, 6.6%, and 16.5%, respectively, in a clinical range of less than 10 kBq/mL. A 3.6% maximum relative difference was found between experimental and simulated sensitivities. The simulated spatial resolution was better than the experimental one. Simulated image quality metrics were relatively close to the experimental results. Conclusions The current model is able to reproduce the behaviour of the DMI count rates in the clinical range and generate clinical-like images with a reasonable match in terms of contrast and noise.

There has been a strong interest in using neural networks to solve several tasks in PET medical imaging. One of the main problems faced when using neural networks is the quality, quantity, and availability of data to train the algorithms. In order to address this issue, we have developed a pipeline that enables the generation of voxelized synthetic PET phantoms, simulates the acquisition of a PET scan, and reconstructs the image from the simulated data. In order to achieve these results, several pieces of software are used in the different steps of the pipeline. This pipeline solves the problem of generating diverse PET datasets and images of high quality for different types of phantoms and configurations. The data obtained from this pipeline can be used to train convolutional neural networks for PET reconstruction.

This paper reviews the ecosystem of GATE, an open-source Monte Carlo toolkit for medical physics. Based on the shoulders of Geant4, the principal modules (geometry, physics, scorers) are described with brief descriptions of some key concepts (Volume, Actors, Digitizer). The main source code repositories are detailed together with the automated compilation and tests processes (Continuous Integration). We then described how the OpenGATE collaboration managed the collaborative development of about one hundred developers during almost 20 years. The impact of GATE on medical physics and cancer research is then summarized, and examples of a few key applications are given. Finally, future development perspectives are indicated.

This study compares the PRIMO and GATE Monte Carlo simulation toolkits for modeling photon beams from a TrueBeam STx Linac used in radiation therapy. Various beam configurations were evaluated against Varian's Golden Beam Data using the Gamma Index method. Both toolkits demonstrated good agreement overall, with GATE generally achieving higher gamma pass rates for percent depth dose curves than PRIMO. [ABSTRACT FROM AUTHOR]

Speech emotion recognition (SER) is a key branch in the field of artificial intelligence, focusing on the analysis and understanding of emotional content in human speech. It involves a multidisciplinary knowledge of acoustics, phonetics, linguistics, pattern recognition, and neurobiology, aiming to establish a connection between human speech and emotional expression. This technology has shown broad application prospects in the medical, educational, and customer service fields. With the evolution of deep learning and neural network technologies, SER research has shifted from relying on manually designed low-level descriptors (LLDs) to utilizing complex neural network models for extracting high-dimensional features. A perennial challenge for researchers has been how to comprehensively capture the rich emotional features. Given that emotional information is present in both time and frequency domains, our study introduces a novel time–frequency domain convolution module (TFCM) based on Mel-frequency cepstral coefficient (MFCC) features to deeply mine the time–frequency information of MFCCs. In the deep feature extraction phase, for the first time, we have introduced hybrid dilated convolution (HDC) into the SER field, significantly expanding the receptive field of neurons, thereby enhancing feature richness and diversity. Furthermore, we innovatively propose the residual attention-gated multilayer perceptron (RA-GMLP) structure, which combines the global feature recognition ability of GMLP with the concentrated weighting function of the multihead attention mechanism, effectively focusing on the key emotional information within the speech sequence. Through extensive experimental validation, we have demonstrated that TFCM, HDC, and RA-GMLP surpass existing advanced technologies in enhancing the accuracy of SER tasks, fully showcasing the powerful advantages of the modules we proposed. [ABSTRACT FROM AUTHOR]

BACKGROUND: Periodontal disease affects over 50% of the global population and is characterized by gingivitis as the initial sign. One dental health issue that may contribute to the development of periodontal disease is foreign body gingivitis (FBG), which can result from exposure to some kinds of foreign metal particles from dental products or food. OBJECTIVE: We design a novel, portable, affordable, multispectral X-ray and fluorescence optical microscopic imaging system dedicated to detecting and differentiating metal oxide particles in dental pathological tissues. A novel denoising algorithm is applied. We verify the feasibility and optimize the performance of the imaging system with numerical simulations. METHODS: The designed imaging system has a focused X-ray tube with tunable energy spectra and thin scintillator coupled with an optical microscope as detector. A simulated soft tissue phantom is embedded with 2-micron thick metal oxide discs as the imaged object. GATE software is used to optimize the systematic parameters such as energy bandwidth and X-ray photon number. We have also applied a novel denoising method, Noise2Sim with a two-layer UNet structure, to improve the simulated image quality. RESULTS: The use of an X-ray source operating with an energy bandwidth of 5 keV, X-ray photon number of 108, and an X-ray detector with a 0.5 micrometer pixel size in a 100 by 100-pixel array allowed for the detection of particles as small as 0.5 micrometer. With the Noise2Sim algorithm, the CNR has improved substantially. A typical example is that the Aluminum (Al) target's CNR is improved from 6.78 to 9.72 for the case of 108 X-ray photons with the Chromium (Cr) source of 5 keV bandwidth. CONCLUSIONS: Different metal oxide particles were differentiated using Contrast-to-Noise ratio (CNR) by utilizing four different X-ray spectra. [ABSTRACT FROM AUTHOR]

This study is aimed to validate 90Y dosimetry with MC simulation by comparing the TLD measurements results obtained in 3D liqid phantom (LP) and its monte carlo (MC) simulation. In the first step, tumor imitation was filled with 1900 µCi (70.3 MBq) amount of 99mTc activity in LP. In addition, 24 thermoluminescence dosimetry chips (TLD-100) were placed in 8 different locations in the LP. The same measurement system was created in GEANT4 Tomography Emission Application (GATE version 8.1). DoseActor library was defined for 24 points instead of TLDs and doses were taken. In the second step, 90Y with the amount of 2 mCi (74 MBq) activity and 27 DoseActor libraries were placed in tumor mimic and different locations in LP to calculate the dose distribution with GATE. GATE and TLD results for 99mTc were compared for validation. The strong correlation coefficient was calculated between the instant absorbed dose rates obtained via TLD measurements and GATE calculations as R2 = 0.994. At the 90Y dosimetry, the highest, lowest and mean cumulative absorbed doses calculated by GATE for a half-life were found to be 1.166 × 102 ± 3.907 × 10–1, 5.440 × 101 ± 2.597 × 10–1, and 75.145 ± 0.303 Gy in the tumor imitation, and 1.167 × 101 ± 1.777 × 10−1, 9.929 × 10−5 ± 6.905 × 10−5, 1.169 ± 0.019 Gy in the liver parenchymal tissue imitation, respectively. GATE program is considered to be a promising application in internal radionuclide dosimetry, based on linear correlation between TLD and GATE measurements in our study. [ABSTRACT FROM AUTHOR]

Accurate knowledge of where jets hit downstream of dams helps designers a lot in locating plunging pools. The purpose of this study is to investigate experimentally and numerically the trajectory of pressurized jets through the gates and to determine their location downstream of the dam. Ansys - Fluent software was used for numerical simulation. The results showed that there is a significant difference between the experimental values and the values extracted from the jet projectile equations for predicting the path of the pressurized jets, and this discrepancy may be due to the effect of air resistance on flow. The existing jet trajectory equations don’t consider air resistance. To minimize this difference, the projectile equation was modified. Also, the effect of changing the diameter of the dam gate and the discharge on the point of impact of the pressurized jet on the ground surface was examined. By increasing the diameter of the dam outlet at a constant discharge, the location of impact of the impinging jet to the ground from the dam toe decreases, and with increasing discharge at a constant diameter of outlet, the place of impact of the pressurized jet to the ground from the toe of the dam increases. In addition, the numerical simulation results showed that the dynamic pressure as well as the velocity at the point of impingement of the jets on the river bed have the maximum value that should be considered in designs. The dynamic pressure as well as the velocity of the jet coming out of the gate hit the ground with an average increase of 145% and 242% relative to the end edge of the gate, respectively. In addition, the breaking length of the pressurized jet was investigated in this study, and it was found that the breaking length of the pressurized jet increases with the increase in the initial velocity of the water jet.

Background: Positron Emission Mammography (PEM) is a nuclear medicine imaging tool, playing a significant role in the diagnosis of patients with breast cancer. These days, many research has been done in order to improve the performance of this system. Objective: This study aims to propose a new method for optimizing the size of axial Field of View (FOV) in PEMs and improving the performance of the systems. Material and Methods: In this analytical study, a conventional Inveon PET is simulated using GATE in order to validate the simulation. For this simulation, the mean relative difference is 2.91%, showing the precision and correction of simulation and consequently it is benchmarked. In the next step, for design of the new optimized detector, several validated simulations are performed in order to find the best geometry. Results: The best result is obtained with the axial FOV of 101.7 mm. It has 1.6×1.6×15 mm3 lutetium yttrium orthosilicate (LYSO) crystals. The detector consists of 6 block rings with 30 detector blocks in each ring. In this paper, the performance of the scanner is improved and the geometry is optimized. Sensitivity and scatter fraction of the designed scanner are 4.65% and 21.2%, respectively, also noise equivalent count rate (NECR) is 105.442 kcps. Conclusion: The results showed 1 up to 3% improvement in the sensitivity of this new detector compared with different PEMs.

BackgroundX-ray image quality relies heavily on the emitted X-ray photon number which depends on X-ray tube current and exposure time. To accurately estimate the absorbed dose in an imaging protocol, it is better to simulate the X-ray imaging with a Monte Carlo platform such as GATE (Geant4 Application for Tomographic Emission). Although input of GATE is the X-ray photon number of the simulated X-ray tube, it lacks a good way to setup the photon number for a desired X-ray tube current setting.ObjectiveTo provide a method to correlate the experimental X-ray tube current exposure time and the X-ray photon number in GATE.MethodsThe accumulated radiation dose of a micro-computed tomography (CT) X-ray tube was recorded at different current exposure times with a general-purpose ion chamber. GATE was used to model the experimental microCT imaging system and calculate the total absorbed dose (cGy) in the sensitive volume of the ion chamber with different X-ray photon numbers. Linear regression models are used to establish a correlation between the estimated X-ray photon number and the X-ray tube settings. At first, one model establishes the relationship between the experimentally measured dose and the X-ray tube setting. Then, another model establishes a relationship between the simulated dose and the X-ray number in GATE. At last, by correlating these two models, a regression model to estimate the X-ray output number from an experimental X-ray tube setting (mAs) is obtained.ResultsFor a typical micro-CT scan, the X-ray tube is operated at 50 kVp and 0.5 mA for a 500 ms exposure time per projection (0.25 mAs). For these X-ray imaging parameters, the X-ray number per projection is estimated to be 3.613×106 with 1.0 mm Al filter.ConclusionThe findings of this work provide an approach to correlate the experimental X-ray tube current exposure time to the X-ray photon number in the GATE simulation of the X-ray tube to more accurately determine radiation dose for an imaging protocol.

In time-of-flight positron emission tomography (TOF-PET), a coincidence time resolution (CTR) below 100 ps reduces the angular coverage requirements and, thus, the geometric constraints of the scanner design. Among other possibilities, this opens the possibility of using flat-panel PET detectors. Such a design would be more cost-accessible and compact and allow for a higher degree of modularity than a conventional ring scanner. However, achieving adequate CTR is a considerable challenge and requires improvements at every level of detection. Based on recent results in the ongoing development of optimised TOF-PET photodetectors and electronics, we expect that within a few years, a CTR of about 75 ps will be be achievable at the system level. In this work, flat-panel scanners with four panels and various design parameters were simulated, assessed and compared to a reference scanner based on the Siemens Biograph Vision using NEMA NU 2-2018 metrics. Point sources were also simulated, and a method for evaluating spatial resolution that is more appropriate for flat-panel geometry is presented. We also studied the effects of crystal readout strategies, comparing single-crystal and module readout levels. The results demonstrate that with a CTR below 100 ps, a flat-panel scanner can achieve image quality comparable to that of a reference clinical scanner, with considerable savings in scintillator material.

Spinal osteoarthritis, a degenerative condition of the spine, significantly impairs quality of life, causing pain, stiffness, and limited mobility. Treatment primarily aims to improve functionality and quality of life. This study investigated the effects of lower back surgery (e.g., spinal decompression with vertebra stabilization) on upper-limb maximum strength, lower limb functionality, and quality of life in osteoarthritis patients. A total of 16 patients (♀ = 10 and ♂ = 6) patients from the orthopedic clinic who were diagnosed with osteoarthritis based on MRI and clinical symptoms underwent the surgery. Their handgrip strength, lower limb functionality (6 min walk test), and quality of life (Flanagan quality of life scale) were assessed before and after the surgery. A repeated measures ANOVA was conducted to assess differences in these metrics pre- and post-surgery across the entire patient cohort, as well as within gender-specific subgroups. A large positive effect was seen in the 6 min walk (p = 0.02, d = −0.83) test but not in the handgrip test or quality of life. However, female patients showed a trend towards better quality of life. The results of this study provide evidence for the effectiveness of surgery in the treatment of spinal osteoarthritis and underscore the need for personalized treatment approaches in the treatment of spinal osteoarthritis.

ObjectiveCerenkov photons have distinctive features from scintillation photons. Among them is their polarization: their electric field is always perpendicular to the direction of propagation of light and parallel to the plane of incidence. Scintillation photons are instead considered unpolarized.ApproachThis study aims at understanding and optimizing the reflectance of polarized Cerenkov photons for optical Monte Carlo simulation of scintillation detectors with Geant4/GATE. First, the Cerenkov emission spectrum and polarization were implemented in the previously developed look-up-table Davis model of crystal reflectance. Next, we modified Geant4/GATE source code to account for scintillation and Cerenkov photons LUTs simultaneously. Then, we performed optical Monte Carlo simulations in BGO using GATE to show the effect of Cerenkov features on the photons' momentum at the photodetector face, using two surface finishes, with and without reflector.Main resultsIn this work, we describe the new features added to the algorithm and GATE. We showed that Cerenkov characteristics affect their probability to be reflected/refracted and thus their travel path within a material.SignificanceWe showed the importance of accounting for accurate Cerenkov photons reflectance while performing advanced optical Monte Carlo simulations.

While the conventional parallel-hole collimators are widely used in myocardial perfusion imaging (MPI) with SPECT, they are suboptimal in balancing the existing sensitivity-resolution compromise. Therefore, multi-pinhole collimation has been proposed to address the problem. In the present study, a channel multi-pinhole collimated SPECT scanner is modeled and then simulated using the GATE Monte Carlo simulation. The multi-pinhole collimator comprises eight apertures. The material, diameter, and height of the apertures were assumed to be varying. A comparison with conventional single-pinhole was also conducted. The results show that increasing the hole diameter leads to degraded spatial resolution for the multi-pinhole collimator. Compared to the single-pinhole, the multi-pinhole collimators suffer from projection overlapping and thus deteriorated spatial resolution. The findings confirm that the channel multi-pinhole collimators outperform the single-pinhole apertures by providing much higher sensitivity at the expense of slightly lower spatial resolution and therefore would be the collimator of choice for MPI with SPECT.

Abstract Background Monte Carlo (MC) simulations are used in nuclear medicine imaging as they provide unparalleled insight into processes that are not directly experimentally measurable, such as scatter and attenuation in an acquisition. Whilst MC is often used to provide a ‘ground-truth’, this is only the case if the simulation is fully validated against experimental data. This work presents a quantitative validation for a MC simulation of a single-photon emission computed tomography (SPECT) system. Methods An MC simulation model of the Mediso AnyScan SCP SPECT system installed at the UK National Physical Laboratory was developed in the GATE (Geant4 Application for Tomographic Emission) toolkit. Components of the detector head and two collimator configurations were modelled according to technical specifications and physical measurements. Experimental detection efficiency measurements were collected for a range of energies, permitting an energy-dependent intrinsic camera efficiency correction function to be determined and applied to the simulation on an event-by-event basis. Experimental data were collected in a range of geometries with $$^{99\text {m}}$$ 99 m Tc for comparison to simulation. The procedure was then repeated with $$^{177}$$ 177 Lu to determine how the validation extended to another isotope and set of collimators. Results The simulation’s spatial resolution, sensitivity, energy spectra and the projection images were compared with experimental measurements. The simulation and experimental uncertainties were determined and propagated to all calculations, permitting the quantitative agreement between simulated and experimental SPECT acquisitions to be determined. Statistical agreement was seen in sinograms and projection images of both $$^{99\text {m}}$$ 99 m Tc and $$^{177}$$ 177 Lu data. Average simulated and experimental sensitivity ratios of ( $$0.991 \pm 0.011$$ 0.991 ± 0.011 ) were seen for emission and scatter windows of $$^{99\text {m}}$$ 99 m Tc, and ( $$0.897 \pm 0.014$$ 0.897 ± 0.014 ) and ( $$0.839 \pm 0.014$$ 0.839 ± 0.014 ) for the 113 and 208 keV emissions of $$^{177}$$ 177 Lu, respectively. Conclusions MC simulations will always be an approximation of a physical system and the level of agreement should be assessed. A validation method is presented to quantify the level of agreement between a simulation model and a physical SPECT system.

The article developed a gating technique that allows us to validate ADS-B data without the necessity to verify using the secondary surveillance radar or multilateration. Probabilistic models of the ADS-B data gating technique, as well as the algorithm for applying these models were proposed. Benchmark cases that occur when aircraft (A/C) positioning by ADS-B systems, determined by threshold values of navigation and pilot’s errors, were analyzed. The first benchmark case assumes not exceeding of navigation and pilot’s errors the bounds of the tolerance limits, which allows us to draw up a conclusion concerning the ADS-B data validation. The second one assumes exceeding of a pilot’s error the bounds of the tolerance limits under an allowable navigational error. Herewith, the air traffic controller (ATC) obtains a message about the proper ADS-B operation and the necessity to issue instructions to the pilot to correct a flight. The third benchmark case assumes exceeding of a navigation error the bounds of the tolerance limits under an allowable or not allowable pilot’s error. In this case, the ATC obtains a message about not valid ADS-B data and the incapability to use these systems. The simulation of the given benchmark cases was performed. In addition, the Rayleigh and Rice distributions were applied to implement the ADS-B data gating technique. The simulation results allow us to assess the required amount of accumulated ADS-B data for the evaluation. Thus, it was found that during the estimate based on the Rayleigh distribution, it is sufficient to accumulate 15–20 measurements, which, when transmitting 2 messages per second and under the condition of the normal ADS-B equipment operation, will take 8–10 s. During the estimate, using the Rice distribution, an accumulation of 25–30 measurements is sufficient, which will take 13–20 s. The developed method will allow the use of ADS-B systems at regional aerodromes with the low intensity of air traffic as the primary or sole surveillance means.

The gallium monochalcogenides family, comprising gallium sulfide (GaS), gallium selenide (GaSe), and gallium telluride (GaTe), is capturing attention for its applications in energy storage and production, catalysis, photonics, and optoelectronics. This interest originates from their properties, which include an optical bandgap larger than those of most common transition metal dichalcogenides, efficient light absorption, and significant carrier mobility. For any application, stability to air exposure is a fundamental requirement. Here, we perform a comparative study of the stability of layered GaS, GaSe, and GaTe nanometer-thick films down to a few layers with the goal of identifying the most suitable Ga chalcogenide for future integration in photonic and optoelectronic devices. Our study unveils a trend of decreasing air stability from sulfide to selenide and finally to telluride. Furthermore, we demonstrate a hydrogen passivation process to prevent the oxidation of GaSe with a higher feasibility and durability than other state-of-the-art passivation methods proposed in the literature. [ABSTRACT FROM AUTHOR]

Background: The "Geant4 Application for Tomography Emission" (GATE) toolkit comprises advanced open-source Monte Carlo (MC) code for use in medical imaging and radiotherapy simulations. This study aimed to verify the GATE toolkit results against a water phantom and then to show the dose calculation capabilities of the GATE for radiotherapy. The results were compared with three dose calculation algorithms using patients' Computerized Tomography (CT) data. Materials and Methods: A Linac with a 6 MV photon beam was simulated in the GATE code. The code was verified, head CT images of three patients were inserted into the GATE as realistic phantoms, and simulations were performed for different field sizes and angles. The Percent Depth Doses (PDDs) and transverse profiles were extracted from the GATE simulation and calculation algorithms. Their results were compared regarding the Dose Difference (DD) and gamma index for the PDDs and the Full Width at Half Maximum (FWHM) for the profiles. Results: Using the patient CT data for the PDDs, the gamma pass rate with 3%/3 mm criteria in the comparison between the GATE simulation and algorithms for all fields ranged from 89.4% to 9 8.8%, with an average of 92.8%. The extracted FWHMs from the GATE and algorithms were in good agreement, and their differences ranged from 0.1 to 1.2 mm. Conclusions: The GATE MC toolkit has good potential for implementation in radiotherapy Treatment Planning Systems (TPS) for dose calculations. [ABSTRACT FROM AUTHOR]

Background: Endovascular aortic repair (EVAR) is generally performed with bi/trimodular stent-grafts requiring retrograde contralateral gate cannulation (CGC). In the case of tricky CGC, an increased EVAR procedural time and radiation exposure have been reported. Herein, we compare the outcomes of conventional CGC and CGC using the speed gate cannulation (SGC) technique in standard EVAR for a propensity-matched cohort. Methods: A total of 371 patients were retrospectively analyzed. Inclusion criteria were fulfilled in 172 patients who underwent propensity score matching. Primary outcomes included operative time, CGC time, mean contrast medium, fluoroscopy time, and CGC fluoroscopy time. Results: After matching, 78 patients were included in each group (SGC vs. standard). Primary outcomes registered a significant reduction in CGC time (4 [1–6] vs. 8 [6–14] min; p = 0.001) and fluoroscopy time (12 [9–16] vs. 17 [12–25] min). Conclusions: In this preliminary experiment, the use of SGC was feasible with no significant registered postoperative complications. A significant reduction in contrast medium usage, radiation exposure, and CGC time was observed with the use of SGC. SGC is a simple adjunctive technique, and its use should be considered in standard EVAR, especially in emergency scenarios, where time is of the essence. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to determine the percentage depth dose (PDD) of a phantom material made from soy-lignin bonded Rhizophora spp. particleboard coated with a gloss finish by using Monte Carlo Geant4 Application for Tomographic Emission (GATE) simulation. Materials and Methods: The particleboard was fabricated using a hot pressing technique at target density of 1.0 g·cm-3 and the elemental fraction was recorded for the simulation. The PDD was simulated in the GATE simulation using the linear accelerator Elekta Synergy model for the water phantom and Rhizophora phantom, and the results were compared with the experimental PDD performed by several studies. Beam flatness and beam symmetry were also measured in this study. Results: The simulated PDD for Rhizophora and water was in agreement with the experimental PDD of water with overall discrepancies of 0% to 8.7% at depth ranging from 1.0 to 15.0 cm. In the GATE simulation, all the points passed the clinical 3%/3 mm criterion in comparison with water, with the final percentage of 2.34% for Rhizophora phantom and 2.49% for the water phantom simulated in GATE. Both the symmetries are all within the range of an acceptable value of 2.0% according to the recommendation, with the beam symmetry of the water phantom and Rhizophora phantom at 0.58% and 0.28%, respectively. Conclusions: The findings of this study provide the necessary foundation to confidently use the phantom for radiotherapy purposes, especially in treatment planning. [ABSTRACT FROM AUTHOR]

PurposeDesigning and optimizing scintillator-based gamma detector using Monte Carlo simulation is of great importance in nuclear medicine and high energy physics. In scintillation detectors, understanding the light transport in the scintillator and the light collection by the photodetector plays a crucial role in achieving high performance. Thus, accurately modeling them is critical.MethodsIn previous works, we developed a model to compute crystal reflectance from the crystal 3D surface measurement and store it in look-up tables to be used in the Monte Carlo simulation software GATE. The relative light output comparison showed excellent agreement between simulations and experiments for both polished and rough surfaces in several configurations, that is, without and with reflector. However, when comparing them at the irradiation depth closest to the photodetector face, rough crystals with a reflector overestimated the predicted light output. Investigating the cause of this overestimation, we optimized the LUT algorithm to improve the reflectance computation accuracy, especially for rough surfaces. However, optical Monte Carlo simulations carried out with these newly generated LUTs still overestimate the light output. Based on previous observations, one probable cause is the erroneous assumption of perfect couplings between the reflector and crystal and between the crystal and photodetector, which likely results in an important overestimation of the light output compared to experimental values. In practice, several factors could degrade it. Here, we investigated possible suboptimal optical experimental configurations that could lead to a degraded light collection when using Teflon or ESR reflectors coupled to the crystal with air or grease. We generated look-up tables with a mixture of air and grease and showed the effect of three possible sources of light loss: the presence of a small gap between the crystal and the reflector edges close to the photodetector face, the infiltration of grease in the crystal-reflector coupling, and the presence of inhomogeneities in the photodetector-crystal interface.ResultsThe strongest effect is linked to the presence of a small gap of grease between the edges of the reflector material and the crystal (light loss of 10%-12% for 0.2 mm gap). The optical grease infiltrating the crystal-reflector air coupling decreases the light output, depending on the infiltration's extent and the amount of grease infiltrated. Five percent of air in the crystal-photodetector coupling can cause a light output decrease of 2% to 4%. The individual and combined effect of these advanced models can explain the discrepancy of the relative light output obtained with ESR in simulations and experiments. With Teflon, the study indicates that the light output loss strongly depends on the reflectance deterioration caused by grease absorption.ConclusionsOur results indicate that when studying scintillation detector performance with different finishes, performing simulations in ideal coupling conditions can lead to light output overestimation. To perform an accurate light output comparison and ultimately have a reliable detector performance estimation, all potential sources of practical limitations must be carefully considered. To broadly enable high-fidelity modeling, we developed an interface for users to compute their own LUTs, using their surface, scintillator, and reflector characteristics.