High-performance Imaging Research Articles

A multiplexing method based on multidimensional readout method.


To develop and validate a novel multidimensional readout method that significantly reduces the number of readout channels in PET detectors while maintaining high spatial and energy performance.

Approach:
We arranged a 3×3×4 SiPM array in multiple dimensions and employed row/column/layer summation with a resistor-based splitting circuit. We then applied denoising methods to enhance the peak-to-valley ratio in the decoding map, ensuring accurate crystal-position determination. Additionally, we investigated the system's energy response at 511 keV and evaluated the suitability for both clinical and research PET systems.

Main Results:
The proposed multidimensional readout method achieved a favorable multiplexing ratio, lowering the total number of readout channels without compromising energy resolution at 511 keV. Our tests demonstrated that a SiPM bias voltage of 31 V effectively balances gain and saturation effects, resulting in reliable energy measurements.

Significance:
By reducing system complexity, cost, and power consumption, the multidimensional readout method presents a practical alternative to conventional readout schemes for PET and other large-scale sensor arrays. Additionally, the approach can manage simultaneous multi-layer hits by arranging detector layers and, when needed, uses ICS detection to correct for scatter events. Its adaptable architecture allows scaling to higher dimensions for broader applications (e.g., SPECT, CT, LiDAR). These features make it a valuable contribution toward more efficient, high-performance imaging technologies in both clinical and industrial settings.

Dynamically switchable edge-detection and bright-field imaging based on a phase-change nonlocal metasurface.

Optical metasurfaces offer significant advantages in enhancing the speed, efficiency, and miniaturization of imaging systems. However, most existing metasurfaces are limited to static functionalities and lack reconfigurability, which is a key feature for practical applications in dynamic environments. In this work, we demonstrate a reconfigurable optical metasurface capable of switching between two distinct imaging functions (edge detection and bright-field imaging) within the visible spectrum. This reconfigurability is achieved by tuning the phase transition of antimony sulfide (Sb2S3), which controls the angular dependence of the magnetic dipole resonance. The phase transition of Sb2S3 from the amorphous phase to the crystalline phase enables different optical transfer functions, achieving high-performance imaging with a numerical aperture of 0.42, isotropic second-order differentiation, and high-resolution imaging, respectively. This approach allows for functional switching on a single surface, opening up possibilities for applications in medical imaging, optical sensing, and microscopy.

Less Is More: Donor Engineering of a Stable Molecular Dye for Bioimaging in the NIR-IIb Window.

Fluorescence molecular imaging aims to enhance clarity in the region of interest, particularly in the near-infrared IIb window (NIR-IIb, 1500-1700 nm). To achieve this, we developed a novel small-molecule dye, named DA-5, based on classic cyanine dyes (heptamethine or pentamethine is essential for wavelengths beyond 1000 nm). By reducing excessive polymethine to a single methine and disrupting symmetry to form an asymmetric donor-π-acceptor (D-π-A) architecture, we enhanced the donor's electron-donating capability, yielding emission at 1088 nm. DA-5 exhibits superior properties, including excellent chemo- and photostability, resistance against solvatochromism-caused quenching, and antiaggregation in aqueous solution. With a large Stokes shift (241 nm) and high brightness (321 M-1 cm-1), DA-5 enables high-performance imaging of the lymphatic system, intestinal vessels, whole-body angiography, and cerebral and hindlimb microvasculature in NIR-IIb. This molecular design strategy offers a promising platform for advancing in vivo biophotonics.

High-performance chalcogenide fiber bundle for mid-wave infrared imaging.

Flexible infrared image fiber bundles (FBs) are capable of delivering thermal images of areas that are difficult for ordinary thermal cameras to access while making the imaging systems compact and lightweight. Thus, FB-based thermal imaging systems show great potential in some important applications, such as infrared endoscopy, aircraft infrared warning, and satellite remote sensing. In most applications, FBs are required to have high overall transmittance (OT) and high spatial resolution (R), but the fabrication of such high-performance FBs is still a challenge. In this work, we demonstrate a new design of flexible mid-wave infrared chalcogenide FB with high OT and decent R by optimizing the composition of glass cladding and geometric parameters of single fibers. The FB is fabricated by a modified approach combining the stack-and-draw technique and layer-stacking method, and the thermal image delivery performance of the FB is comprehensively characterized. It is shown that the core diameter (d core) and core/cladding diameter ratio (R cc) of single fibers can be balanced to reduce leakage of the light propagating in the single fibers while making the FB retain a reasonably high filling factor. Thus a high-performance FB can be achieved. The fabricated FB consists of 124,200 single fibers featuring an As40S60 core, an As38.9S61.1 cladding, and a polyetherimide (PEI) protective coating, with a dcore of ∼22.8 µm and an Rcc of 0.8. It has a length of ∼52 cm and a filling factor of ∼50.2%. The FB presents excellent thermal image delivery performance, including an OT of 40.5%, a single-fiber loss of 1.71 dB/m at 4.6 µm, and an R of 20.2 lp/mm, which compares favorably to previously reported FBs. These findings provide new insights for the development of high-performance thermal imaging FBs and lay a foundation for their practical applications.

Hyaluronic acid-functionalized supramolecular nanophotosensitizers for targeted photoimmunotherapy of triple-negative breast cancer

Triple-negative breast cancer (TNBC) is recognized as a particularly aggressive subtype of breast cancer that is devoid of effective therapeutic targets. Immune checkpoint inhibitors (ICIs) have demonstrated promising results in TNBC treatment. Nonetheless, most patients either develop resistance to ICIs or fail to respond to them initially. Owing to its spatio-temporal precision and non-invasive nature, photoimmunotherapy offers a targeted therapeutic strategy for TNBC. Herein, we report hyaluronic acid (HA)-functionalized indocyanine green-based supramolecular nanoparticles (HGI NPs), with biodegradable characteristics, for high-performance photoacoustic imaging and targeted phototherapy for TNBC. Notably, HGI NPs can significantly gather in TNBC tissues because of the enhanced permeability and retention effect of the tumor, and the tumor-targeting properties of HA. The strong amplification of HGI nanoparticles triggers a significant immunogenic cell death (ICD) response when exposed to 808 nm light, thus shifting the immunosuppressive tumor microenvironment (iTME) into a tumor attack mode and ‘hot’ state. Antitumor experiments demonstrate the high efficiency of the supramolecular photosensitizers HGI NPs for TNBC elimination and good biosafety. This synergistic strategy reshapes the iTME and amplifies the antitumor immune response, providing a theoretical foundation for combining phototherapy and ICIs as potential treatments for TNBC.Graphical

Composition-Tunable Bandgap Engineering of Horizontally Guided CdSxSe1-x Nanowalls for High-Performance Photodetectors.

Composition-adjustable semiconductor nanomaterials have garnered significant attention due to their controllable bandgaps and electronic structures, providing alternative opportunities to regulate photoelectric properties and develop the corresponding multifunction optoelectronic devices. Nevertheless, the large-scale integration of semiconductor nanomaterials into practical devices remains challenging. Here, we report a synthesis strategy for the well-aligned horizontal CdSxSe1-x (x = 0-1) nanowall arrays, which are guided grown on an annealed M-plane sapphire using chemical vapor deposition (CVD) approaches. Microstructural characterizations demonstrate these structures as horizontally guided nanowalls with high-quality crystallinity. Microphotoluminescence (μ-PL) reveals the CdSxSe1-x nanowalls exhibiting continuously tunable spontaneous emissions from 509 nm (pure CdS) to 713 nm (pure CdSe), further confirming that CdSxSe1-x alloys have a continuously tunable bandgap. Notably, a photodetector based on CdSxSe1-x nanowalls displays excellent photoelectric performance, such as high responsivity (3 × 102 ∼ 1 × 103 A/W), high external quantum efficiency (1.01 × 103 ∼ 2.93 × 103), and fast response speed in the millisecond magnitude. Furthermore, the CdS nanowall-based photodetectors exhibit a remarkable image-sensing capability, indicating potential applications in high-performance image sensing in the future. Bandgap continuously tunable nanowall arrays with high-quality crystallinity inject great vitality into the manufacturing of high-performance integrated optoelectronic devices.

High-Performance Perovskite Flat Panel X-Ray Imagers via Blade Coating.

Perovskite X-ray detectors are recognized as the most promising candidates for low-dose detectors due to their superior performance. However, it is still full of challenging in the fabrication of flat-panel X-ray imagers (FPXIs), primarily due to the absence of large area thick films that exhibit high uniformity and long-term performance stability. A general synthesis route is urgently needed to grow large-scale halide perovskite thick films directly on a pixeled thin-film transistor (TFT) backplane with high uniformity, closing the gap between the great potential of perovskite X-ray detectors and their entry into the market. In this work, an advanced precursor paste suitable for blade coating is developed to enable high-throughput manufacturing of FPXIs. Highly uniform perovskite films with a thickness of 300-micrometers are directly deposited onto pixeled TFT substrates by the blade-coating method using the above paste, which governs a stable dark current and minimal noise of the X-ray detectors. As a result, (BA)2(MA)9Pb10I31 perovskite X-ray detectors achieved a high sensitivity of 15200 µC Gyair -1 cm-2 and a limit of detection (LoD) of 26.8 nGyair s-1. Moreover, FPXIs with a spatial resolution of 0.95 lp mm-1 (0.475 lp pixel-1) are obtained, which exhibits negligible signal crosstalk and excellent X-ray imaging performance.

Next step in Moore’s law: high NA EUV system overview and first imaging and overlay performance

Next step in Moore’s law: high NA EUV system overview and first imaging and overlay performance

Transparent ultrasonic transducers based on relaxor ferroelectric crystals for advanced photoacoustic imaging

Photoacoustic imaging is a promising non-invasive functional imaging modality for fundamental research and clinical diagnosis. However, achieving capillary-level resolution, wide field-of-view, and high frame rates remains challenging. To address this, we propose a transparent ultrasonic transducer design using our developed transparent Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 crystals. Our fabrication technique incorporates quartz-glass-and-epoxy matching layers with low-resistance indium-tin-oxide electrodes through a brass-ring based structure, enabling a high frequency (28.5 MHz), wide bandwidth (78%), and enhanced pulse-echo sensitivity (2.5 V under 2-μJ pulse excitation). Our Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3-based transparent ultrasonic transducer demonstrates a four-fold enhancement in photoacoustic detection sensitivity when compared to the LiNbO3-based counterpart, leading to a 13 dB improvement of signal-to-noise ratio in microvascular photoacoustic imaging. This enables dynamic monitoring of mouse cerebral cortex microvasculature during seizures at 0.8 Hz frame rates over a 1.5 × 1.5 mm2 field-of-view. Our work paves the way for high-performance and compact photoacoustic imaging systems using advanced piezoelectric materials.

Large Scale Lead-Free Perovskite Polycrystalline Wafer Achieved by Hot-Pressed Strategy for High-Performance X-Ray Detection.

Halide perovskites (HPs) have demonstrated excellent direct X-ray detection performance. Lead-free perovskite polycrystalline wafers have outstanding advantages in large-area X-ray imaging applications due to their area-scalability, thickness-controllability, large bulk resistivity, and ease of integration with large-area thin film transistor arrays. However, currently lead-free perovskite polycrystalline wafers possess low sensitivity, typically less than 1000 µC Gy-1 cm-2, which severely limits their X-ray detection applications. Here, high-quality and large scale polycrystalline wafers of AG3Bi2I9 (AG: aminoguanidinium) with short intercluster distances are successfully prepared using a hot-pressing method. The wafers possess high mobility-lifetime product of 5.66 × 10-3 cm2 V-1 and therefore achieve high X-ray sensitivity of 2675 µC Gy-1 cm-2, which can be comparable to those of the high-quality single crystal counterpart reported by the previous research (7.94 × 10-3 cm2 V-1 and 5791 µC Gy-1 cm-2), and represent the best results of the currently lead-free HP polycrystalline wafers. Besides, the wafers exhibit the X-ray detection limit as low as 11.8 nGy s-1, excellent long-term working stability, and high spatial resolution of 5.9 lp mm-1 in imaging. The findings demonstrate that AG3Bi2I9 polycrystalline wafers are feasible for high-performance X-ray detection and imaging system.

Sequentially amplified integration of catalytic DNA circuits for high-performance intracellular imaging of miRNA and interpretation of mRNA-miRNA signalling pathway

The cascaded catalytic circuits are viable tools for improving the signal gain of biosensors, yet their sensing performance is still limited by the signal leakage from complex biological environment and unsatisfying reaction efficiency from inter-reactants steric hindrance. Herein, we proposed a catalytically localized DNA (CLD) circuit for the accurate and high-efficiency imaging of microRNA (miRNA) in living cells by virtue of the sequentially and successively amplified integration of catalytic DNA circuits. The compact CLD circuit was constructed by integrating two elemental catalytic circuits, cell-responsive EDR module and analyte-sensing CHA module, where CHA module was initially caged in EDR module for eliminating the unwanted off-site and off-target signal leakage. Only by cell-specific messenger RNA (mRNA)-activated EDR operation then the elemental CHA circuit could be successively connected to facilitate the highly efficient intramolecular reaction with low steric hindrance, thus leading to accelerated reaction efficiency for miRNA analyte. The multiple molecular recognition and the spatial self-confinement of the smart CLD circuit enable the accurate and high-efficiency imaging of intracellular miRNA. The interaction network of mRNA and miRNA was then investigated in situ through our CLD circuit, which provides a powerful tool for discovering the underlying signal pathways between these different RNAs in living cells.

DDoCT: Morphology preserved dual-domain joint optimization for fast sparse-view low-dose CT imaging.

Computed tomography (CT) is continuously becoming a valuable diagnostic technique in clinical practice. However, the radiation dose exposure in the CT scanning process is a public health concern. Within medical diagnoses, mitigating the radiation risk to patients can be achieved by reducing the radiation dose through adjustments in tube current and/or the number of projections. Nevertheless, dose reduction introduces additional noise and artifacts, which have extremely detrimental effects on clinical diagnosis and subsequent analysis. In recent years, the feasibility of applying deep learning methods to low-dose CT (LDCT) imaging has been demonstrated, leading to significant achievements. This article proposes a dual-domain joint optimization LDCT imaging framework (termed DDoCT) which uses noisy sparse-view projection to reconstruct high-performance CT images with joint optimization in projection and image domains. The proposed method not only addresses the noise introduced by reducing tube current, but also pays special attention to issues such as streak artifacts caused by a reduction in the number of projections, enhancing the applicability of DDoCT in practical fast LDCT imaging environments. Experimental results have demonstrated that DDoCT has made significant progress in reducing noise and streak artifacts and enhancing the contrast and clarity of the images.

Solution processed hundred-micron scale vertical growth of low-symmetrical zero-dimensional metal halide for high-performance X-ray imaging

Solution processed hundred-micron scale vertical growth of low-symmetrical zero-dimensional metal halide for high-performance X-ray imaging

Noninvasive high-resolution deep-brain photoacoustic imaging with a negatively focused fiber-laser ultrasound transducer

Noninvasive high-resolution deep-brain imaging is essential to fundamental cognitive process study and neuroprotective drugs development. Although optical microscopes can resolve fine biological structures with good contrast without exposure to ionizing radiation or a strong magnetic field, the optical scattering limits the penetration depth and hinders its capability for deep-brain imaging. Here, in vivo high-resolution imaging of the whole mouse brain is demonstrated by using a photoacoustic computed tomography system with a negatively focused fiber-laser ultrasound transducer. By leveraging the high flexibility and low bending loss of the optical fiber, a rationally designed negatively focused fiber laser cavity exhibits a low detection limit down to 5.4 Pa and a broad view angle of ∼120 deg, enabling mouse brain imaging with a penetration larger than 7 mm and a nearly isotropic spatial resolution of ∼130 μm. In addition, the negative curvature of the fiber laser reduces the working distance, which facilitates the development of a compact and portable linear scanning imaging system. In vivo imaging of a mouse model with intracerebral hemorrhage is also showcased to demonstrate its capability for potential biomedical and clinical applications. With high spatial resolution and large tissue penetration, the system may provide a noninvasive, user-friendly, and high-performance imaging solution for biomedical research and preclinical/clinical diagnosis.

Inverse Design of Aberration-Corrected Hybrid Metalenses for Large Field of View Thermal Imaging Across the Entire Longwave Infrared Atmospheric Window.

Long wave infrared (LWIR) cameras play a pivotal role across diverse applications due to their distinctive features. The growing demand for high-performance thermal imaging optics, characterized by a broad working bandwidth, large field of view (FOV), aberration-free design, lightweight construction, compactness, and cost-effectiveness, poses significant challenges for LWIR lens design. Here, we propose an inverse design method for LWIR hybrid metalenses, specifically aiming to achieve aberration-corrected thermal imaging with both a large FOV and a broad working bandwidth. Our approach involves optimizing phase profiles of metalens' unit cells guided by a loss function that compares the hybrid lens design to diffraction-limited results for various incident angles and wavelengths. As a result, we demonstrate an aberration-corrected thermal camera with a 30° FOV and an achromatic working bandwidth spanning the entire LWIR atmospheric window (8 to 14 μm). Significantly, the total optical path length, the entrance pupil to the sensor plane of the charge-coupled device (CCD), is a mere 13.6 mm. Our work merits advantages in the FOV, working bandwidth, and compactness, which surpass state-of-the-art LWIR hybrid metalens designs and find numerous imaging and sensing applications.

Enhanced dual-mode imaging: Superior photoacoustic and ultrasound endoscopy in live pigs using a transparent ultrasound transducer.

Dual-mode photoacoustic/ultrasound endoscopy (ePAUS) is a promising tool for preclinical and clinical interventions. To be clinically useful, ePAUS must deliver high-performance ultrasound imaging comparable to commercial systems and maintain high photoacoustic imaging performance at long working distances. This requires a transducer with an intact physical aperture and coaxial alignment of acoustic and optical beams within the probe, a challenging integration task. We present a high-performance ePAUS probe with a miniaturized, optically transparent ultrasonic transducer (TUT) called ePAUS-TUT. The 1.8-mm-diameter probe, fitting into standard endoscopic channels, aligns acoustic and optical beams efficiently, achieving commercial-level ultrasound and high-resolution photoacoustic imaging over long distances. These imaging capabilities were validated through in vivo imaging of a rat's rectum and a pig's esophagus. The ePAUS-TUT system substantially enhances feasibility and potential for clinical applications.

UTHP spectrometer: an ultra-thin and high-performance imaging spectrometer for ocean color remote sensing in broadband

The principle of ocean color detection involves using satellite sensors to capture variations in received signals, which are subsequently analyzed to infer the concentrations of various components responsible for ocean color changes. In recent years, significant research advancements have been achieved, centered on the development of ocean color detectors and the analysis of the resulting data. We have developed an innovative ultra-thin high-performance (UTHP) scanning imaging spectrometer for ocean color remote sensing across the near ultraviolet-visible-near infrared (NUV-VIS-NIR) spectrum. This spectrometer overcomes the bulkiness of conventional equipment by integrating a waveguide platform that replaces traditional optical elements with a single flat glass panel, featuring curved surfaces and high-reflectivity coatings to perform essential optical functions. We believe this to be a novel design that greatly reduces the size and weight of the device, making it highly suitable for deployment on various platforms, including aircraft and satellites. The optical system underwent extensive testing, including simulations using Zemax software and physical prototyping, achieving a spectral resolution of less than 3 nm across the 400-1000 nm waveband while maintaining low distortion. The UTHP spectrometer’s compactness, lightweight design, and exceptional performance mark a significant advancement in imaging spectrometry, with the potential to transform remote sensing by providing more efficient, accessible methods for studying expansive oceanic regions.

Analysis of Quantum-Classical Hybrid Deep Learning for 6G Image Processing with Copyright Detection

This study investigates the integration of quantum computing, classical methods, and deep learning techniques for enhanced image processing in dynamic 6G networks, while also addressing essential aspects of copyright technology and detection. Our findings indicate that quantum methods excel in rapid edge detection and feature extraction but encounter difficulties in maintaining image quality compared to classical approaches. In contrast, classical methods preserve higher image fidelity but struggle to satisfy the real-time processing requirements of 6G applications. Deep learning techniques, particularly CNNs, demonstrate potential in complex image analysis tasks but demand substantial computational resources. To promote the ethical use of AI-generated images, we introduce copyright detection mechanisms that employ advanced algorithms to identify potential infringements in generated content. This integration improves adherence to intellectual property rights and legal standards, supporting the responsible implementation of image processing technologies. We suggest that the future of image processing in 6G networks resides in hybrid systems that effectively utilize the strengths of each approach while incorporating robust copyright detection capabilities. These insights contribute to the development of efficient, high-performance image processing systems in next-generation networks, highlighting the promise of integrated quantum-classical–classical deep learning architectures within 6G environments.

MCI Net: Mamba- Convolutional lightweight self-attention medical image segmentation network.

With the development of deep learning in the field of medical image segmentation, various network segmentation models have been developed. Currently, the most common network models in medical image segmentation can be roughly categorized into pure convolutional networks, Transformer-based networks, and networks combining convolution and Transformer architectures. However, when dealing with complex variations and irregular shapes in medical images, existing networks face issues such as incomplete information extraction, large model parameter sizes, high computational complexity, and long processing times. In contrast, models with lower parameter counts and complexity can efficiently, quickly, and accurately identify lesion areas, significantly reducing diagnosis time and providing valuable time for subsequent treatments. Therefore, this paper proposes a lightweight network named MCI-Net, with only 5.48 M parameters, a computational complexity of 4.41, and a time complexity of just 0.263. By performing linear modeling on sequences, MCI-Net permanently marks effective features and filters out irrelevant information. It efficiently captures local-global information with a small number of channels, reduces the number of parameters, and utilizes attention calculations with exchange value mapping. This achieves model lightweighting and enables thorough interaction of local-global information within the computation, establishing an overall semantic relationship of local-global information. To verify the effectiveness of the MCI-Net network, we conducted comparative experiments with other advanced representative networks on five public datasets: X-ray, Lung, ISIC-2016, ISIC-2018, and capsule endoscopy and gastrointestinal segmentation. We also performed ablation experiments on the first four datasets. The experimental results outperformed the other compared networks, confirming the effectiveness of MCI-Net. This research provides a valuable reference for achieving lightweight, accurate, and high-performance medical image segmentation network models.

Ultracompact optical microscopes made of liquid crystal Pancharatnam–Berry optical elements

Ultracompact optical systems are increasingly sought after for applications such as consumer electronics and medical imaging. Here, we present a design and manufacturing approach for ultracompact bright- and dark-field optical microscopes entirely made of flat liquid crystal optical elements. Both systems utilize liquid crystal PB lenses as objective and tube lenses, while the dark-field optical microscope incorporates an additional Q-plate with a +1 topological defect to filter zero-order light. We demonstrate two optical microscopic systems with a numerical aperture of 0.25 and overall thickness of just 5 mm. The system can achieve high imaging performance with a resolution better than 7 µm. We further demonstrate an exemplary application in biological imaging to effectively enhance edge contrast in imaging onion epidermal cells. This work presents an example in exploiting the flatness and high quality of liquid crystal optical elements to achieve compactness and high-quality imaging promising for various applications.