Search Results (1,362)

Imaging techniques used for the care of cutaneous melanoma patients have greatly changed over the past century, from symptom-driven radiography toward a multimodality framework integrated for staging, directing surgery, and systemic therapy, and surveillance. Historically, clinical evaluation and skin exams have been the tenets of melanoma diagnosis and staging. In recent years, noninvasive imaging, such as dermoscopy, total-body photography and reflectance confocal microscopy, has expanded the diagnostic toolset for primary melanoma detection. Concurrently, several imaging techniques have been developed to detect metastases and follow disease progression, including computed tomography (CT), magnetic resonance imaging (MRI), fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT), lymphoscintigraphy, and single-photon emission computed tomography/computed tomography (SPECT/CT). The use of immune checkpoint inhibitors has also altered imaging interpretation by introducing atypical response patterns, including pseudoprogression, requiring immune-adapted assessment frameworks such as Immune Response Evaluation Criteria in Solid Tumors (iRECIST). While there is a strong consensus for high-risk patients, imaging techniques and surveillance schedules for low-risk patients (stage I/II) remain controversial due to limited supporting evidence and conflicting data on costs and patient benefit. The development of new technologies, including image-guided surgery, non-FDG PET tracers, phone apps, artificial intelligence-assisted image analysis, and radiomics, may further change melanoma imaging. The aim of this review is to detail the historical evolution of melanoma imaging, the development of new imaging techniques, and their role and future in clinical practice. Full article

Background: Myocardial perfusion scintigraphy (MPS) is widely used for noninvasive assessment of coronary artery disease, but publicly available datasets suitable for reproducible deep learning segmentation studies remain limited. This paper proposes CardioProto-SegNet, an image-only 3D anatomy-directed segmentation framework for myocardial region delineation using the public Myocardial Perfusion Scintigraphy Image Database v1.0.0 from PhysioNet, which contains 83 patient studies. Methods: The model is implemented as a 3D U-Net-like residual encoder–decoder network enhanced with squeeze-and-excitation channel recalibration and compact prototype-memory refinement at the bottleneck. Because the public dataset does not provide structured clinical variables, all reported results correspond to image-only myocardium segmentation. Results: Experimental evaluation demonstrated reliable segmentation performance on the available public dataset. CardioProto-SegNet achieved a Dice score of 0.7402 on the holdout test split. In five-fold cross-validation, the model obtained a mean Dice of 0.8239, mean IoU of 0.6870, mean accuracy of 0.9943, mean ROC-AUC of 0.9867, and mean PR-AUC of 0.8561. Since confirmed ischemia or infarction labels were not available, an exploratory image-derived subgroup analysis was additionally performed based on myocardial ROI uptake heterogeneity to examine model behavior in lower- and higher-heterogeneity cases. The ablation study showed that residual connections were important for stable segmentation performance, while the deeper variant achieved the highest tested performance, with a Dice score of 0.8290, IoU of 0.7096, and PR-AUC of 0.8831. Conclusions: Overall, the findings suggest that CardioProto-SegNet provides a reproducible public dataset benchmark for myocardium segmentation in MPS and may serve as a foundation for future downstream quantitative and CAD-oriented analysis when larger datasets with clinical labels become available. Full article

Passive daytime radiative cooling (PDRC) materials require high solar reflectance and high atmospheric window emissivity. However, high solar reflectance achieved by scattering strategies often relies on porous structures, which can compromise the material’s mechanical reliability. To address this trade-off, we develop a layered alumina nanofiber membrane (LANM) by dual-nozzle electrospinning with programmed alternating deposition, in which alternating deposition and subsequent removal of alumina precursor layers and sacrificial polyvinyl alcohol (PVA) interlayers generate a continuously layered architecture with periodic interfaces and interlayer air gaps. This interfacial geometric design enables simultaneous regulation of solar-band scattering and bending load transfer within a single alumina system. Because photon flux attenuates with depth, shallow interfaces contribute more strongly than deeper ones; therefore, the micro-layered architecture enhances scattering while maintaining high emissivity in the atmospheric window. In outdoor testing, LANM achieved a maximum sub-ambient temperature reduction of ~5.8 °C, representing a further improvement of about 2.4 °C compared to Monolithic alumina nanofiber (ANM). Moreover, interlayer interfaces induce a multiple-neutral-axis mechanism and segmented stress transfer, thereby improving bending deformability rather than load-bearing strength. Full article

Conventional 8YSZ thermal barrier ceramics suffer from limited phase stability and insufficient infrared radiation regulation at high temperatures. Sc₂O₃ doping can reduce thermal conductivity and improve phase stability, but the improvement remains limited because the fixed-valence substitution of Sc³⁺ cannot effectively increase defect concentration or regulate carrier behavior. In this work, CeO₂ with tunable valence states was incorporated into the Sc-stabilized YSZ system to realize the synergistic modulation of lattice thermal conductivity and photon thermal conductivity. A series of Sc₂O₃–CeO₂ co-doped YSZ ceramics were fabricated via solid-state sintering, and the effects of co-doping on phase structure, defect evolution, thermal conductivity, infrared emissivity, and bandgap characteristics were systematically investigated. The results show that all co-doped samples maintained a stable tetragonal fluorite structure with relative densities higher than 96%. Among them, Sc_0.08Ce_0.005Y_0.005Zr_0.91O₂ exhibited the best comprehensive performance. Its thermal conductivity at 1000 °C reached 2.073 W·m⁻¹·K⁻¹, which was 11.9% lower than that of conventional 8YSZ. Meanwhile, the average infrared emissivity in the 3–5 μm band increased to 0.779. XPS analysis indicated that Ce incorporation promoted oxygen-vacancy formation, which enhanced phonon scattering and reduced lattice thermal conductivity. In addition, co-doping narrowed the band gap and facilitated carrier excitation, thereby strengthening infrared absorption and emission behavior. The enhanced infrared emissivity further contributed to the suppression of radiative thermal transport at elevated temperatures. This work demonstrates that Sc₂O₃–CeO₂ co-doping provides an effective strategy for simultaneously regulating phonon transport and photon transport in YSZ-based ceramics. The results provide new insight into the design of advanced thermal barrier materials with low thermal conductivity and enhanced high-temperature infrared radiation performance. Full article

The modernization of traditional Chinese medicine (TCM) is significantly impeded by the elusive material basis of its meridian system and by a lack of objective, quantitative diagnostic standards. Recent breakthroughs in photonic technologies and optoelectronic chips offer transformative paradigms to address these systemic bottlenecks. This review systematically evaluates the complete academic and engineering chain of “Photonic TCM,” spanning fundamental mechanisms, optical diagnostics, advanced therapeutics, and core chip-level technologies. Specifically, we analyze how ultra-weak photon emission (UPE), two-photon microscopy, and infrared thermography can objectify meridian dynamics and acupuncture pathways. For clinical translation, laser acupuncture has emerged as a robust, non-invasive modality for managing disorders such as chronic pain and insomnia, supported by cumulative evidence-based data. At the device level, vertical-cavity surface-emitting laser (VCSEL)-based photonic computing chips enable ultrafast herbal medicine recognition, while flexible optoelectronics and lab-on-a-chip systems lay the technical groundwork for wearable neuromodulation. Crucially, this review concludes that the Photonic TCM paradigm is transitioning from isolated clinical validation to integrated engineering implementation. We identify biological tissue scattering and parameter heterogeneities as the primary bottlenecks. To navigate these challenges, we propose that the field’s future should converge toward edge-computing-driven wearable closed-loop systems and multi-dimensional optical big data ecosystems. Ultimately, these technological trajectories will steer TCM from an empirical discipline toward a data-driven, precise, and standardized medical science. Full article

In this work, we investigate deterministic chaos in external-cavity semiconductor lasers with delayed optical self-feedback. A noise-free quadrature-based delay differential model is used to isolate the intrinsic nonlinear dynamics produced by phase-sensitive delayed reinjection and carrier–photon interactions. Sensitivity to initial conditions is quantified by computing the leading Lyapunov exponents through a variational approach that integrates the base delay differential equations together with their delayed variational equations using a fourth-order Runge–Kutta method of steps and periodic QR orthonormalization. High-resolution Lyapunov maps are constructed in the $({\log }_{10}C,{\varphi }_f)$ parameter space for different pump ratios and selected short-feedback delays. The delay values are interpreted through the reference-normalized ratio ${\tau }_f/T_{R,\mathrm{ref}}$, where $T_{R,\mathrm{ref}}\approx 131.9\mathrm{ps}$ is a fixed reference timescale derived from a reference solitary-laser operating point. The results show that both the spatial organization of positive-${\lambda }_1$ regions and the mean positive Lyapunov exponent are strongly affected by feedback delay, feedback phase, feedback strength, and pump ratio. Within the selected short-delay set, delayed self-feedback produces broader, more connected, and more strongly unstable chaotic regions as the external-cavity memory time increases toward the fixed reference timescale, particularly at larger pump ratios. These findings show that short external-cavity self-feedback can support robust deterministic chaotic regimes relevant to compact and integrated photonic implementations. The proposed framework provides a reproducible deterministic reference for identifying and interpreting feedback-induced chaos in short-delay external-cavity semiconductor lasers, while stochastic effects such as spontaneous-emission and Langevin noise are left for future robustness studies. Full article

Light-converting polymer coatings and films are emerging passive photonic materials for spectral engineering in sustainable and protected agriculture. By absorbing ultraviolet or weakly used spectral components and re-emitting in visible bands that overlap with photosynthetic pigments and plant photoreceptor action regions, these materials can modify the radiation environment without additional electrical energy input. This critical narrative review analyses light-converting polymer films and coatings from a materials and coatings perspective, with emphasis on photophysical mechanisms, polymer matrices, luminophore families, coating fabrication routes, optical transparency, photoluminescence, aggregation phenomena, photostability and scalability. The photobiological background is included as a concise framework that justifies the spectral targets of the conversion process. Rare-earth complexes, inorganic phosphors, quantum dots, aggregation-induced-emission systems and organic dyes are compared as candidate luminophores. Particular attention is devoted to the general challenges associated with organic luminescent coatings, including dispersion, aggregation, optical transparency, photostability, and scalability. A PMMA/PDI coating system is discussed only as an illustrative case study demonstrating these broader materials-design considerations. Extrusion, solution casting, spin-coating, dip-coating and sol–gel processing are evaluated as fabrication strategies for laboratory and large-area greenhouse applications. The work concludes by identifying the main gaps that must be addressed before practical deployment: quantitative UV–Vis and photoluminescence characterization, absolute quantum yield, haze and scattering, thickness and morphology mapping, accelerated UV aging, weathering resistance, toxicity assessment and crop-specific validation. Full article

Quantum dot (QD) color conversion technology has attracted considerable attention in QD-OLED displays because it enables the generation of highly pure red and green emissions from blue OLED excitation with reduced fabrication complexity. Mixed QD color conversion layers consisting of red and green QDs dispersed in a polydimethylsiloxane matrix were fabricated to improve red color conversion efficiency and suppress blue leakage. The color conversion characteristics of the mixed QD layers were investigated by varying the QD contents and layer thicknesses. The color conversion spectra, blue leakage characteristics, color conversion efficiency, and output/input efficiency were systematically analyzed. Compared with red QD-only layers, the mixed QD layers exhibited more effective suppression of blue leakage and stronger red emission even at relatively small layer thicknesses. The red QD-only layer containing 100 mg of red QDs exhibited a color conversion efficiency of 16.7% at a thickness of 38 µm, whereas the mixed QD layer with the same red QD content achieved a higher color conversion efficiency of 19.3% at a thickness of only 5.6 µm. The enhanced color conversion efficiency of the mixed QD layers is likely associated with increased absorption of blue photons and additional excitation of red QDs through photon reabsorption and possible energy transfer processes between the green and red QDs. Full article

In medicine, nanoparticles are used for various purposes, including theranostics, imaging, diagnostics, drug delivery, tissue regeneration and targeted cancer treatments, and to minimize the harmful side effects associated with conventional therapies. Target-specific biomolecules, such as silica nanoparticles (SiNPs) labeled with metallic radionuclides, are becoming increasingly popular. The choice of radionuclide is based on its nuclear properties. Silica has several advantages for nanoparticle synthesis, including high biocompatibility, the capacity for drug encapsulation due to its porous structure, and the potential for extensive surface functionalization, including radiolabeling for imaging and therapeutic applications. A radionuclide can be attached to a silica nanoparticle either directly or through the use of chelators or polymers. Additionally, the capability to encapsulate therapeutic agents within such systems offers significant potential for the development of targeted therapies. This study aims to provide a comprehensive overview of recent developments in the radiolabeling of silica-based nanoparticles, with a focus on their application in nuclear medicine, particularly in diagnostic imaging and targeted radionuclide therapy. Theranostics employs a range of imaging modalities to guide and monitor therapeutic interventions. Principal techniques include positron emission tomography (PET), single-photon emission computed tomography (SPECT), magnetic resonance imaging (MRI), and Optical Imaging (such as fluorescence and bioluminescence). These imaging methods enable precise visualization of pathological sites, facilitate tracking of therapeutic agent distribution, and permit real-time assessment of treatment efficacy. Full article

Reconfigurable photonic metasurfaces enable tunable thermal-emission engineering in the long-wave infrared (LWIR), particularly within the 8–13 μm atmospheric window. This work includes the investigation on a concentric-ring VO₂/SiO₂/Au metasurface for LWIR spectral-emissivity modulation. Full-wave simulations showed that, in the metallic phase (σ = 2 × 10⁵ S/m where σ is conductivity), the structure exhibited an absorption over 90% across the 9.3–15 μm sub-band, with two near-unity resonances near 10.2 and 13.3 μm. Control structures, gap-dependent spectra, E-field maps, and current-density Cartesian multipole decomposition supported a hybridized-ring mechanism in which both dominant resonances were predominantly electric-dipole-like ring branches whose spectral positions and field localizations were modified by inter-ring coupling. Across the conductivity sweep, the normal-incidence band-averaged 8–13 μm emissivity changed from 0.0184 to 0.8844, corresponding to a switching ratio of 48.06. The four-fold symmetry of unit cell also yielded polarization-insensitive and angularly robust LWIR absorption, while the simplified endpoint thermal-balance estimate indicated a metallic-state net cooling power of 49.3 W m⁻² at T = T_amb = 300 K, where T_amb was the ambient temperature, and an estimated equilibrium temperature drop of 4.4 K below the ambient for the metallic-state endpoint, whereas the insulating-state one suppressed this response. These results identify concentric VO₂ ring metasurfaces as promising candidates for switchable LWIR thermal-emission control. Full article

Background/Objectives: Single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is widely used for non-invasive assessment of coronary artery disease under stress and rest conditions. Although deep learning has shown promise for automated SPECT MPI interpretation, most studies focus on single-tracer datasets and do not explicitly account for tracer-dependent variability. This study developed and evaluated a multi-task deep learning framework with tracer-specific prediction heads for patient-level SPECT MPI classification. Methods: A convolutional neural network with a shared feature encoder and tracer-specific heads was implemented using polar map representations from technetium-99m (Tc-99m) and thallium-201 (Tl-201) studies. Transfer learning from ImageNet was applied. Stress-only, rest-only, and dual-input configurations were evaluated using repeated patient-stratified cross-validation and independent testing. Performance was assessed using ROC-AUC and balanced accuracy. Results: For Tc-99m normal versus abnormal perfusion classification, the stress-only model achieved the highest cross-validation AUC (0.88 ± 0.067) and test AUC of 0.88 [0.67–0.99]. For Tl-201 low-risk versus intermediate/high-risk classification, stress-based models achieved the highest cross-validation AUC (0.88 ± 0.051) and test AUC of 0.80 [0.71–0.89], comparable to dual-input models. In both tracer-specific tasks, stress-phase information showed favorable performance, but the endpoints differed and should be interpreted separately. Conclusions: Stress-phase polar maps provided strong discriminative information within this single-center cohort. These findings should be interpreted in a tracer- and task-specific manner supporting stress-phase imaging as an informative input for AI-based SPECT MPI classification while underscoring the need for external validation before broader clinical generalization. Full article

Dicarbadodecaboranes (12) (carboranes) are versatile molecular building blocks with unique properties, which allow the expansion of classical medicinal-chemical space. To enable single-photon emission computed tomography (SPECT) imaging of cyclooxygenase-2 (COX-2), we investigated the feasibility of introducing iodine-123 into nido-indoborin 1, a nido-carborane analog of indomethacin with potent and selective cyclooxygenase-2 inhibitory activity. An electrophilic iodination strategy afforded two regioisomers, 2a and 2b, bearing the iodine at the carborane cluster. Compared to nido-indoborin, a reduced COX-2 inhibition potency and selectivity were observed, with 2b exhibiting the more favorable inhibition profile. Radiosynthesis of [¹²³I]2b was achieved by N-chlorosuccinimide–mediated electrophilic substitution of 1, and conditions were optimized, leading to an isolated radiochemical yield of 4%. While the radiotracer displayed high stability in phosphate buffer, ester hydrolysis was observed in human plasma and murine liver microsomes with no significant deiodination in vitro. Cell uptake studies indicated partial COX-2–dependent accumulation but also revealed substantial non-specific uptake and unexpected enhancement of radiotracer uptake in the presence of carborane-based blocking agents. In vivo pilot imaging studies in mice bearing U87 xenografts showed renal and hepatobiliary clearance without measurable tumor accumulation but evidence of deiodination over time. Overall, iodination was feasible, but the resulting compounds lacked the required COX-2-selective tumor accumulation for further radiotracer development. Full article

Emerging metallic radionuclides are expanding theranostic capabilities in nuclear medicine by improving diagnostic sensitivity, enabling dosimetry, and matched theranostic approaches. ¹⁴⁹Tb, ⁴⁴Sc, ⁵²Mn, ²⁰³Pb, and ⁵⁵Co offer distinct nuclear decay properties, including extended half-lives, variable positron emissions, and prompt γ-photons that may influence quantitative imaging performance. Cyclotron and generator routes integrating enriched targets and optimized separations support clinical-scale supply, while advances in chelation chemistry improve in vivo stability and imaging performance. Preclinical and early clinical data demonstrate that ¹⁴⁹Tb provides intrinsic α-therapy and PET imaging capability for theranostic use, ⁴⁴Sc enables extended imaging relative to ⁶⁸Ga, supporting delayed imaging and improved tumor-to-background contrast for peptide-based radiopharmaceuticals and theranostic applications. ⁵²Mn supports prolonged biological tracking for antibody- and engineered-protein-targeted studies, whereas ²⁰³Pb serves as a diagnostic surrogate for ²¹²Pb based α-therapy (via ²¹²Bi). ⁵⁵Co PET imaging supports the development and evaluation of ^58mCo Auger electron therapy. Current challenges include limited global availability of highly enriched targets, management of long-lived radioactive by-products, and the need for standardized dosimetry and regulatory pathways to ensure reproducibility and safety. Ongoing developments in automated target handling, optimized separations, next-generation chelators, and harmonized regulation may facilitate broader clinical translation. Full article

Introduction: Progressive supranuclear palsy (PSP) is an atypical Parkinsonian disorder characterized by a range of clinical phenotypes, reflecting its multiple subtypes. As a result, accurate diagnosis during life remains challenging, underscoring the need for reliable biomarkers. The present narrative review aims to evaluate whether dopamine transporter single-photon emission computed tomography (DaT-SPECT) can serve as a biomarker in the assessment of PSP. Methods: The database search identified 31 original research articles relevant to our study objective. Of these, 17 studies included PSP patients and utilized DaT-SPECT as the sole molecular imaging modality; 9 studies combined DaT-SPECT with at least one additional molecular imaging technique; and 5 studies integrated DaT-SPECT with a laboratory-based biomarker of neurodegenerative disease. Results: DaT-SPECT appears to demonstrate low specificity and variable sensitivity for PSP across studies. Discussion: Combining DaT-SPECT with other diagnostic biomarkers, especially brain magnetic resonance imaging and other nuclear imaging modalities, may improve diagnostic accuracy, especially given its relatively low specificity for PSP. Nevertheless, these initially promising findings need to be validated in large, multicenter studies that include and clearly define multiple, autopsy-confirmed PSP subtypes. Full article

Background/Objectives: Revascularization of chronic total occlusions (CTO) in patients with heart failure and reduced ejection fraction (HFrEF) remains controversial, as randomized trials have not demonstrated a clear prognostic benefit. Methods: We present an imaging-guided case series of patients with ischemic HFrEF who underwent CTO percutaneous coronary intervention (PCI) following myocardial viability assessment using single-photon emission computed tomography (SPECT). Contemporary antegrade and retrograde techniques were employed. Results: At 6- and 12-month follow-ups, all patients demonstrated marked improvement in NYHA (New York Heart Association) functional class, significant reductions in NT-proBNP (N-terminal pro-brain natriuretic peptide) levels, and substantial improvement in quality of life assessed by the Minnesota Living with Heart Failure Questionnaire (MLHFQ). These benefits occurred despite only modest improvement in left ventricular (LV) ejection fraction (EF) and limited reverse remodeling. SPECT enabled identification of viable but ischemic myocardium, supporting individualized revascularization decisions. Conclusions: In selected high-risk patients with ischemic HFrEF, CTO-PCI was associated with meaningful clinical and biomarker improvement independent of substantial EF recovery. Careful patient selection, incorporating myocardial viability assessment, may refine individualized clinical decision-making in selected patients. These findings support an imaging-guided approach and warrant further prospective evaluation. Full article