Gate Modulation Research Articles

Multimodal Sentiment Analysis With Image-Text Interaction Network

More and more users are getting used to posting images and text on social networks to share their emotions or opinions. Accordingly, multimodal sentiment analysis has become a research topic of increasing interest in recent years. Typically, there exist affective regions that evoke human sentiment in an image, which are usually manifested by corresponding words in peoples comments. Similarly, people also tend to portray the affective regions of an image when composing image descriptions. As a result, the relationship between image affective regions and the associated text is of great significance for multimodal sentiment analysis. However, most of the existing multimodal sentiment analysis approaches simply concatenate features from image and text, which could not fully explore the interaction between them, leading to suboptimal results. Motivated by this observation, we propose a new image-text interaction network (ITIN) to investigate the relationship between affective image regions and text for multimodal sentiment analysis. Specifically, we introduce a cross-modal alignment module to capture region-word correspondence, based on which multimodal features are fused through an adaptive cross-modal gating module. Moreover, considering the complementary role of context information on sentiment analysis, we integrate the individual-modal contextual feature representations for achieving more reliable prediction. Extensive experimental results and comparisons on public datasets demonstrate that the proposed model is superior to the state-of-the-art methods.

BCTNet: Bi-Branch Cross-Fusion Transformer for Building Footprint Extraction

Building footprint extraction in remote sensing remains challenging due to the diverse appearances of buildings and confusing scenarios. Recently, researchers have revealed that both the globality and locality are vitally important in building footprint extraction tasks and proposed to incorporate the local context and global long-range dependency in the segmentation models. However, the inadequate integration of the globality and locality still leads to incomplete, fake or missing extraction results. To alleviate these problems, a novel segmentation method named Bi-branch Cross-fusion Transformer Network (BCTNet) is proposed in this study. Two parallel branches of the convolutional encoder branch (CB) and the transformer encoder branch (TB) are designed to extract multi-scale feature maps. A concatenation-then-cross-fusion transformer block (CCTB) is put forward to integrate the locality from the CB and globality from the TB in a cross-fusion way at each stage of the encoding process. Then, an adaptive gating module (AGM) is proposed to gate the feature maps from the CCTB to strengthen the important features while suppressing the irrelevant interference information. After that, the segmentation results can be obtained through a simple decoding process. Comprehensive experiments on two benchmark datasets demonstrate that the proposed BCTNet can achieve superior performance compared to the current state-of-the-art (SOTA) segmentation methods.

RAAGR2-Net: A brain tumor segmentation network using parallel processing of multiple spatial frames

Brain tumors are one of the most fatal cancers. Magnetic Resonance Imaging (MRI) is a non-invasive method that provides multi-modal images containing important information regarding the tumor. Many contemporary techniques employ four modalities: T1-weighted (T1), T1-weighted with contrast (T1c), T2-weighted (T2), and fluid-attenuation-inversion-recovery (FLAIR), each of which provides unique and important characteristics for the location of each tumor. Although several modern procedures provide decent segmentation results on the multimodal brain tumor image segmentation benchmark (BraTS) dataset, they lack performance when evaluated simultaneously on all the regions of MRI images. Furthermore, there is still room for improvement due to parameter limitations and computational complexity. Therefore, in this work, a novel encoder–decoder-based architecture is proposed for the effective segmentation of brain tumor regions. Data pre-processing is performed by applying N4 bias field correction, z-score, and 0 to 1 resampling to facilitate model training. To minimize the loss of location information in different modules, a residual spatial pyramid pooling (RASPP) module is proposed. RASPP is a set of parallel layers using dilated convolution. In addition, an attention gate (AG) module is used to efficiently emphasize and restore the segmented output from extracted feature maps. The proposed modules attempt to acquire rich feature representations by combining knowledge from diverse feature maps and retaining their local information. The performance of the proposed deep network based on RASPP, AG, and recursive residual (R2) block termed RAAGR2-Net is evaluated on the BraTS benchmarks. The experimental results show that the suggested network outperforms existing networks that exhibit the usefulness of the proposed modules for “fine” segmentation. The code for this work is made available online at: https://github.com/Rehman1995/RAAGR2-Net.

MCTSR: A super‐resolution method for defects in gas‐insulated switchgear X‐ray images based on multi‐scale contextual transformers

AbstractAs the core equipment of transmission and distribution hubs, the operational status of gas‐insulated switchgear (GIS) is closely linked to the safety of the power system. Recently, X‐ray digital imaging technology has been extensively used in GIS equipment fault detection. However, the X‐ray image of GIS is blurred, which is not conducive to the detection of tiny defects. Thus, a super‐resolution method for GIS X‐ray images based on multi‐scale context transformers is proposed in this study, namely MCTSR. Firstly, a second‐order image degradation model is introduced to generate GIS X‐ray low‐resolution images that more closely resemble the real world. Secondly, a contextual transformer gate module is constructed to improve attention to tiny defects in GIS X‐ray images. Thirdly, a U‐Net discriminator network based on multi‐scale contextual transformers is intended to enrich the information of the generated images. Finally, the proposed discriminator is combined with the existing generator to compose a super‐resolution method applicable to GIS X‐ray images. The experimental results demonstrate that the method outperforms other methods in peak signal‐to‐noise ratio and structural similarity on the constructed GIS X‐ray image dataset. In addition, the output image of the proposed method facilitates the subsequent defect detection.

Improved Subthreshold Characteristics by Back-Gate Coupling on Ferroelectric ETSOI FETs

In this work, extremely thin silicon-on-insulator field effective transistors (ETSOI FETs) are fabricated with an ultra-thin 3 nm ferroelectric (FE) hafnium zirconium oxides (Hf0.5Zr0.5O2) layer. Furthermore, the subthreshold characteristics of the devices with double gate modulation are investigated extensively. Contributing to the advantages of the back-gate voltage coupling effects, the minimum subthreshold swing (SS) value of a 40 nm ETSOI device could be adjusted from the initial 80.8–50 mV/dec, which shows ultra-steep SS characteristics. To illustrate this electrical character, a simple analytical model based on the transient Miller model is demonstrated. This work shows the feasibility of FE ETSOI FET for ultra-low-power applications with dynamic threshold adjustment.

Pixel device based on a quantum well: Preliminary results on gate dielectrics

The development of pixel arrays close to the interaction point in large detector systems used in high energy physics require high radiation hardness for the pixels and their readout. A pixel device based on a quantum well, called the DoTPiX uses a sensing n-channel MOS device with a control gate. A buried Ge layer acts as a current modulation gate, which localize holes generated by impinging particles. The DotPIX buried Ge gate is obtained by low temperature epitaxial growth of Ge on Si. We have started to study the different ways to achieve these prerequisites: the need for a low temperature budget to reduce the Ge and Si intermixing, which may be detrimental to the DoTPiX operation. The use of Si thermal oxide is investigated together with that of deposited oxide (Hafnium Oxide for example), which differs from the Silicon Dioxide. The possibility of a combination of thermal silicon dioxide and deposited oxides opens another possibility in this study.

Dependence of reverse leakage on the edge termination process in vertical GaN power device

The trench gate metal oxide semiconductor field effect transistor (MOSFET) represents a prominent device architecture among the Gallium Nitride (GaN) based vertical devices currently investigated for the next generation of power electronics. A low leakage current level in off-state under high drain bias is of great importance for vertical transistors since it is a crucial feature for high breakdown voltage and device reliability. The off-state drain leakage originates from different sources in the vertical trench gate MOSFET. Besides the trench gate module, the leakage paths at the dry-etched sidewall of the lateral edge termination can also significantly contribute to the off-state drain-current. In this report, the influence of each relevant process step on the drain leakage current in off-state that is related to the lateral edge termination is investigated utilizing specific test structures on high-quality GaN epitaxial material which mimic the lateral edge termination of the MOSFET. Electrical characterization reveals the sensitivity of the leakage current to plasma-related processes. A termination technology is presented that results in low leakage current while including thick dielectric layers from plasma-assisted deposition as intended for fabrication of a field plate structure over the edge termination.

500 °C operation of β-Ga2O3 field-effect transistors

We demonstrated 500 °C operation of field-effect transistors made using ultra-wide bandgap semiconductor β-Ga2O3. Metal–semiconductor field-effect transistors were fabricated using epitaxial conductive films grown on an insulating β-Ga2O3 substrate, TiW refractory metal gates, and Si-implanted source/drain contacts. Devices were characterized in DC mode at different temperatures up to 500 °C in vacuum. These variable-temperature measurements showed a reduction in gate modulation of the drain current due to an increase in gate leakage across the gate/semiconductor Schottky barrier. Devices exhibited a reduction in transconductance with increasing temperature; despite this, drain current increased with temperature due to a reduction in threshold voltage caused by the de-trapping of electrons from deep-level traps. Devices also showed negligible change in semiconductor epitaxy and source/drain contacts, hence demonstrated recovery to their room-temperature electrical properties after the devices were tested intermittently at different high temperatures in vacuum. The mechanism of gate leakage was also explored, which implicated the presence of different conduction mechanisms at different temperatures and gate electric fields.

Biomolecules‐Incorporated Metal‐Organic Frameworks Gated Light‐Sensitive Organic Photoelectrochemical Transistor for Biodetection

AbstractIncorporating biomolecules into metal‐organic frameworks (MOFs) as exoskeletons to form biomolecules‐MOFs biohybrids has attracted great attention as an emerging class of advanced materials. Organic devices have been shown as powerful platforms for next‐generation bioelectronics, such as wearable biosensors, tissue engineering constructs, and neural interfaces. Herein, biomolecules‐incorporated MOFs as innovative gating module is realized for the first time, which is exemplified by biocatalytic precipitation (BCP)‐oriented horseradish peroxidase (HRP)‐embedded zeolitic imidazolate framework‐90 (HRP@ZIF‐90)/CdIn2S4 gated organic photoelectrochemical transistor under light illumination. In connection to a sandwich immunocomplexing targeting the model analyte human IgG, the IgG‐dependent generation of H2O2 and the tandem HRP‐triggered BCP reaction can cause the in situ blocking of the pore network of ZIF‐90, leading to variant gating effect with corresponding responses of the device. This representative biodetection achieved good analytical performance with a wide linear range and a low detection limit of 100 fg mL−1. In the view of the plentiful biomolecule‐MOF complexes and their potential interactions with organic systems, this study provides a proof‐of‐concept study for the generic development of biomolecules‐MOFs‐gated electronics and beyond.

Selective Release of Excitatory‐Inhibitory Neurotransmitters Emulated by Unipolar Synaptic Transistors via Gate Voltage Amplitude Modulation

AbstractOrganic field‐effect transistor (OFET) memory devices are benefiting from their independent gate modulation advantages for hardware implementation of synaptic functionalities. However, the imitation of selective release of excitatory–inhibitory neurotransmitters in a unipolar synaptic OFET is challenging due to the unbalanced mobile carrier concentration. Here, a p‐type synaptic OFET memory with CsPbBr3 quantum dots (QDs) as nano‐floating gates (NFGs) is developed, which can emulate both the excitatory–inhibitory responses of the biological synapse and their reconfigurable nature. By controlling the offset difference between stimulus voltage and reading voltage, the concomitant and independently expressed excitatory and inhibitory responses are successfully implemented in a negative gate modulation manner, but without introducing an ambipolar semiconductor or additional optical terminal. This reconfigurable modulation is ascribed to the dynamic competition between external electric field and built‐in electric field assisted by charge trapping in shallow traps. The proposed gate voltage‐offset method can be generally adapted to other unipolar synaptic OFETs. These results provide insight into OFET memory devices for building neuromorphic hardware elements with tailorable synaptic plasticity.

Retinal Structure Detection in OCTA Image via Voting-Based Multitask Learning.

Automated detection of retinal structures, such as retinal vessels (RV), the foveal avascular zone (FAZ), and retinal vascular junctions (RVJ), are of great importance for understanding diseases of the eye and clinical decision-making. In this paper, we propose a novel Voting-based Adaptive Feature Fusion multi-task network (VAFF-Net) for joint segmentation, detection, and classification of RV, FAZ, and RVJ in optical coherence tomography angiography (OCTA). A task-specific voting gate module is proposed to adaptively extract and fuse different features for specific tasks at two levels: features at different spatial positions from a single encoder, and features from multiple encoders. In particular, since the complexity of the microvasculature in OCTA images makes simultaneous precise localization and classification of retinal vascular junctions into bifurcation/crossing a challenging task, we specifically design a task head by combining the heatmap regression and grid classification. We take advantage of three different en face angiograms from various retinal layers, rather than following existing methods that use only a single en face. We carry out extensive experiments on three OCTA datasets acquired using different imaging devices, and the results demonstrate that the proposed method performs on the whole better than either the state-of-the-art single-purpose methods or existing multi-task learning solutions. We also demonstrate that our multi-task learning method generalizes across other imaging modalities, such as color fundus photography, and may potentially be used as a general multi-task learning tool. We also construct three datasets for multiple structure detection, and part of these datasets with the source code and evaluation benchmark have been released for public access.

Compact Numerical Modeling of Indirect Time-of-Flight CMOS Image Sensors

A pixel-level compact numerical model, including input optical, pixel parameter, modulation gate clock, and readout noise for indirect time-of-flight (i-ToF) sensor, is proposed. The modulation contrast (Cmod) of the pixel and the depth characteristics, including depth accuracy and depth noise, are obtained with the iterative and Monte Carlo methods. The rationality of the demodulation process is verified through the pixel parameter Cmod with technology computer-aided design (TCAD) simulation and test. Then, the prediction results of the depth accuracy under nonideal conditions are obtained, which is consistent with the theoretical analysis and measurements. Finally, the depth noise is characterized. The model results give an excellent agreement with the measurement results. The proposed development of such a compact model presents an essential convenience toward for the design and circuit-level simulation and can provide the prediction of i-ToF sensor characteristics.

Tunable Gain SnS2/InSe Van der Waals Heterostructure Photodetector.

Due to the favorable properties of two-dimensional materials such as SnS2, with an energy gap in the visible light spectrum, and InSe, with high electron mobility, the combination of them can create a novel platform for electronic and optical devices. Herein, we study a tunable gain SnS2/InSe Van der Waals heterostructure photodetector. SnS2 crystals were synthesized by chemical vapor transport method and characterized using X-ray diffraction and Raman spectroscopy. The exfoliated SnS2 and InSe layers were transferred on the substrate. This photodetector presents photoresponsivity from 14 mA/W up to 740 mA/W and detectivity from 2.2 × 108 Jones up to 3.35 × 109 Jones by gate modulation from 0 V to +70 V. Light absorption and the charge carrier generation mechanism were studied by the Silvaco TCAD software and the results were confirmed by our experimental observations. The rather high responsivity and visible spectrum response makes the SnS2/InSe heterojunction a potential candidate for commercial visible image sensors.

Spatial Distribution of Calcium Sparks Determines Their Ability to Induce Afterdepolarizations in Human Atrial Myocytes

Analysis of the spatio-temporal distribution of calcium sparks showed a preferential increase in sparks near the sarcolemma in atrial myocytes from patients with atrial fibrillation (AF), linked to higher ryanodine receptor (RyR2) phosphorylation at s2808 and lower calsequestrin-2 levels. Mathematical modeling, incorporating modulation of RyR2 gating, showed that only the observed combinations of RyR2 phosphorylation and calsequestrin-2 levels can account for the spatio-temporal distribution of sparks in patients with and without AF. Furthermore, we demonstrate that preferential calcium release near the sarcolemma is key to a higher incidence and amplitude of afterdepolarizations in atrial myocytes from patients with AF.

α-Lipoic Acid Derivatives as Allosteric Modulators for Targeting AMPA-Type Glutamate Receptors' Gating Modules.

The ionotropic glutamate receptor subtype α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) is responsible for most excitatory transmission in the brain. AMPA receptor function is altered in numerous neurological illnesses, making AMPA receptors appealing therapeutic targets for clinical intervention. Alpha-Lipoic acid (α-LA) is a naturally occurring compound, which functions as a co-factor in metabolism and energy production. α-LA is an antioxidant with various benefits in treating diabetes, including managing symptomatic diabetic neuropathy. This study will test a novel and innovative strategy to synthesize a new isomer of lipoic acid (R-LA) derivatives (bifunctional NO-donor/antioxidant) in one chemical on homomeric and heteromeric AMPA receptor subunits. We used patch-clamp electrophysiology to examine LA derivatives expressed in human embryonic kidney 293 cells (HEK293) for inhibition and changes in desensitization or deactivation rates. LA derivatives were shown to be potent antagonists of AMPA receptors, with an 8-11-fold reduction in AMPA receptor currents seen following the delivery of the compounds. Furthermore, the LA derivatives influenced the rates of desensitization and deactivation of AMPA receptors. Based on our results, especially given that α-LA is closely connected to the nervous system, we may better understand using AMPA receptors and innovative drugs to treat neurological diseases associated with excessive activation of AMPA receptors.

Evaluation of the feasibility of cardiac gating for SBRT of ventricular tachycardia based on real-time ECG signal acquisition.

To investigate the feasibility of cardiac synchronized gating in stereotactic body radiation therapy (SBRT) of ventricular tachycardia (VT) using a real-time electrocardiogram (ECG) signal acquisition. Stability of beam characteristics during simulated ECG gating was examined by developing a microcontroller interface to a Varian Clinac iX linear accelerator allowing gating at frequencies and duty cycles relevant to cardiac rhythm. Delivery accuracy was evaluated by measuring dose linearity with an ionization chamber, and flatness and symmetry with a two-dimensional detector array, for different gating windows within typical human cardiac cycle periods. To establish a practical method of gating based on actual ECG signals, an AD8232 Heart Monitor board was used to acquire the ECG signal and synchronize the beam delivery. Real-time cardiac gated delivery measurements were performed for a single 10×10cm2 field and for a VT-SBRT plan using intensity-modulated radiation therapy (IMRT). Dose per monitor unit (MU) values were found to be linear within most gating windows investigated with maximum differences relative to non-gated delivery of <2% for gating windows ≥200ms and for >10MUs. Beam profiles for both gated and non-gated modes were also found to agree with maximum differences of 0.5% relative to central axis dose for all sets of beam-on/beam-off combinations. Comparison of dose distributions for intensity-modulated SBRT plans between non-gating and cardiac gating modes provided a gamma passing rate of 97.2% for a 2% 2mm tolerance. Beam output is stable with respect to linearity, flatness, and symmetry for gating windows within cardiac cycle periods. Agreement between dose distributions for VT-SBRT using IMRT in non-gated and cardiac cycle gated delivery modes shows that the proposed methodology is feasible. Technically, gating for delivery of SBRT for VT is possible with regard to beam stability.

Nano-Pattern Oxidation of WSe2 Via Block Copolymer Self-Assembly for Highly Responsive Homojunction Phototransistors

Tungsten diselenide (WSe2), one of the two-dimensional (2D) materials, has emerged as a promising optoelectric candidate because of its thickness dependent bandgap, large optical absorption coefficient, good air stability and high carrier mobility. In addition, the electrical properties of the ambipolar WSe2 could be tuned through the electrostatic doping by the gate modulation. However, the low photo responsivity is a critical problem of WSe2-based optoelectric devices. To overcome this limitation, several approaches have been suggested such as stacking different 2D materials and coating with quantum dots. But these conventional methods were focused on the formation of heterojunctions, which requires complicated alignment process and leads to unavoidable defects and residues. Thus, the novel ways to build homojuction should be investigated for fabricating devices with a clean interface in a simple process.In this work, block copolymer (BCP) was used to prepare hexagonally packed cylinder nano-template as an oxidation mask for UV/ozone treatment, which resulted in numerous nanoscale homojunctions on WSe2. To fabricate the mask with hexagonally packed cylinders, asymmetric poly (styrene-block-methyl methacrylate) (PS-b-PMMA) was spin-coated. After thermal annealing for self-assembly, PMMA was selectively removed by reactive ion etching. UV/ozone treatment, one of the oxidation methods of the WSe2, leads to the formation of the the tungsten oxide (WOX) with high electron affinity and induces a p-doping effect. By using BCP as an oxidation mask, the only region of the WSe2 under the removed PMMA blocks could be converted into WOX.The responsivity of the nano-pattern oxidized WSe2 phototransistor manifests a dramatic change depending on the applied gate bias. The device exhibited a responsivity (532 nm, 8.515 mW/cm2) of 27.5 mA/W under applied gate bias of 0 V. However, under the gate bias of +60 V, the device showed an enhanced responsivity of 155.2 mA/W, as strong p-n junctions were induced. In conclusion, the nano-pattern oxidized WSe2 phototransistor presents increased responsivity (155.2 mA/W), external quantum efficiency (36.3%) and faster response time than the pristine WSe2.This work demonstrates that the responsivity of the WSe2 phototransistor can be improved though well-established perpendicular BCP and optimized by effective modulation of gate bias. By implementing homojunctions on the WSe2 via the nano-pattern oxidation method, this work greatly expands the potential applications of 2D TMDs materials for next-generation nanoscale optoelectronic devices.

(Digital Presentation) Liquid-Metal-Printed Ultra-Thin ITO-Thin-Film Transistor

Indium oxide is one of the promising materials for the n-channel layer for high-mobility oxide-TFT because of its high electron mobility characteristics due to the nature of spatially spread-In 5s orbital. However, excess carrier electrons in In-based channels cancel field-effect gate modulation and causes the formation of a short depletion layer. Moreover, it is challenging to reduce the electron density without the degradation of electron transport. Therefore, developing fully-depletion operated TFT using an ultra-thin channel is a straightforward strategy to demonstrate the high potential of In-based materials for TFT applications.In this work, we developed an ultra-thin tin-doped Indium oxide (ITO) channel (~ 1.9 nm-thick.) and demonstrated a fully-depleted ITO-TFT exhibiting high mobility of 27 cm2/Vs. The ITO channel was grown by a cost-effective vacuum-free liquid-metal-printing route at the maximum process temperature of ~ 200 oC in an ambient atmosphere. Post-thermal annealing in air made significant improvement of device characteristics originating from the reduction of shallow acceptor-like in-gap defects in the ITO channels, and high-performance n-channel ITO-TFT with a large on/off-current ratio of 109 and a sharp threshold slope was achieved. By controlling air-annealing temperature, we also successfully fabricated both enhancement and depletion-mode devices and developed a full signal swinged-oxide-NMOS inverter composed of a depletion-load structure.

Fine-grained modeling of user interests for sequential recommendation

In recent years, the sequential recommendation method has attracted extensive attention owing to its practicability and high accuracy. Different from general recommendations, explicitly capturing short-term interests based on users' recent actions lies at the heart of a sequential recommender. Existing methods have either modeled successive items step by step without considering the many-to-one relationship or neglected the local-order information, considering the recent items as a set. This neither fully mines complex item transitions nor depicts the evolution of user interests. Therefore, we propose the gating coupled capsule network (GCC), a fine-grained analysis method to model individual-level, union-level, and local-order relationships of short-term user interests. Specifically, we designed a user-specific capsule module to capture high-level temporal interaction sequences, which model union-level patterns and perceive local-order relations. Moreover, we present a personalized gating module to focus on the pairwise relationships among items to capture the influence of individual-level information on short-term user interests. Extensive experiments under four real-world recommendation scenarios demonstrate that GCC outperforms the state-of-the-art methods on different ranking metrics.

Polarity status of trigger signal during ECG-gating affects parameters of LV function in gated myocardial perfusion SPECT

Introduction and backgroundThe polarity status is one of the important items of specifications of trigger signal from cardiac trigger monitors with two options, either positive or negative. Some systems allow the user to set the polarity of trigger signal before imaging. Efforts should be made to set the polarity status according to the recommendations provided by the manufacturers. In case of inappropriate selection, changes in computation of end-systolic and end-diastolic volumes as well as ejection fraction may occur. ObjectiveTo investigate the effect of the polarity status of trigger signals in synchronization process during 8- and 16-frame gated SPECT imaging on the systolic and diastolic parameters of LV function. MethodsThirty-four patients referred for a myocardial perfusion SPECT were consecutively included in the study. The rest scan for each patient was performed with 8- and 16-frame gating simultaneously with positive trigger signal set by the operator in a cardiac trigger monitor and then repeated after manual selection of negative polarity. In total, the 4 imaging modes acquired were 8-frame/positive-trigger, 16-frame/positive-trigger, 8-frame/negative-trigger, and 16-frame/negative-trigger. All SPECT images were reconstructed and processed with the same values of parameters. Systolic and diastolic indices of LV function were derived in QGS of the Cedars-Sinai software and then were compared using various statistical tests, and a reliability analysis was also performed. ResultsThe age of patients recruited in the study was 58.41 ± 8.94, and 16 (47.1%) males and 18 (52.9%) females. All the correlation coefficients between corresponding parameters in positive and negative trigger signals were statistically significant. The difference between the parameters of systolic function including EF, EDV, and ESV in positive and negative trigger signals was statistically significant in paired sample t test. Likewise, a statistically significant difference was also found between mean phase angle in scans with positive and negative trigger signals by a phase difference of 147.91 (41.0% of an average cardiac cycle) and 149 (41.3% of an average cardiac cycle) degrees in 8- and 16-frame gating modes, respectively. Strong agreement (according to high values of intra-class correlation coefficient) was found for all four pairs. According to Bland-Altman results, an offset of about 3 percentage units was found, both between imaging in 8-frame gating compared to 16-frame gating, higher value in favor of 16-frame gating, and also between imaging with positive polarity trigger compared to negative-polarity trigger, again higher value in favor of positive-polarity triggering. ConclusionThe status of the polarity of trigger signals or similar CTM-camera delays in synchronization process during 8- and 16-frame gated SPECT imaging can be considered as one of the factors that may influence systolic and diastolic indices of LV function