With the rapid advancement of hemodynamic indices and monitoring technologies, their classification methods and application processes have become increasingly complex. Currently, no unified standard hasbeen established, making it difficult to fully meet the clinical requirements for hemodynamic management. To assist in hemodynamic monitoring assessment and therapeutic decision-making in critically ill patients, the Critical Hemodynamic Therapy Collaborative Group, in conjunction with the Critical Ultrasound Study Group, has jointly developed the Standard for the Application of Hemodynamic Monitoring Techniques in Critical Care. The first part of this standard systematically categorizes hemodynamic indicators into flow indicators, pressure and its derivative indicators, and tissue perfusion indicators, while elaborating on the clinical application of each. The second part establishes a standardized clinical implementation pathway for hemodynamic monitoring. It proposes a tiered monitoring strategy-comprising basic, advanced, indication-specific, and special scenario monitoring-tailored to different clinical settings. It emphasizes the central role of critical care ultrasound across all levels of monitoring and establishes hemodynamic assessment standards for organs such as the brain, kidneys, and gastrointestinal tract. This standard aims to provide a unified framework for clinical practice, teaching, training, and research in critical care medicine, thereby promoting standardized development within the discipline.

ObjectiveTo investigate the effect and mechanism of long intergenic non-coding RNA02086 （LINC02086） overexpression mediated macrophage polarization on the proliferation， migration and invasion of gastric cancer cells. MethodsThe expression levels of LINC02086 in the human gastric epithelial cell line GES-1 and human gastric cancer cell lines HCG-27， NCI-N87， and AGS were determined by qRT-PCR. Human acute monocytic leukemia cells （THP-1） were induced to differentiate into M0 macrophages using phorbol 12-myristate 13-acetate （PMA）. HGC-27 cells were infected with either LINC02086 overexpression lentivirus （OE-LINC02086） or its negative control lentivirus （Vector）， and the culture supernatants were collected as conditioned medium （CM1）. M0 macrophages were co-cultured with the infected HGC-27 cells， and the resulting supernatants were designated as conditioned medium 2 （CM2）. M0 macrophages were treated with CM1 alone or in combination with Wnt/β-catenin pathway inhibitor IWR-1， forming the Vector+CM1， OE-LINC02086+CM1， and OE-LINC02086+CM1+IWR-1 groups， respectively. Flow cytometry was used to detect mannose receptor C-type 1 （CD206） expression， and qRT-PCR was employed to measure mRNA levels of interleukin-10 （IL⁃10）， transforming growth factor-β （TGF⁃β）， vascular endothelial growth factor （VEGF）， and chemokine ligand 22 （CCL22）. Western blot was performed to evaluate protein expression of CD206， VEGF， and key components of the Wnt/β-catenin pathway—Wnt family member 3a （Wnt3a）， glycogen synthase kinase-3β （GSK-3β）， and β-catenin. HGC-27 cells were treated with CM2 alone or combined with IWR-1， establishing the Vector+CM2， OE-LINC02086+CM2， and OE-LINC02086+CM2+IWR-1 groups. CCK-8 assay was used to evaluate cell proliferation， and Transwell assays were conducted to assess migration and invasion capabilities. ResultsCompared with GES-1 cells， the expression levels of LINC02086 were upregulated in HCG-27， NCI-N87， and AGS cells （P < 0.05）， with the smallest increase observed in HCG-27 cells. Compared with Vector+CM1 group， the level of CD206 and the expression levels of IL⁃10， TGF⁃β， VEGF and CCL22 mRNA in macrophages stimulated by OE-LINC02086+CM1 increased （P<0.05）. Meanwhile， the expression levels of Wnt3a and β-catenin proteins in cells increased （P<0.05）， and the expression level of GSK-3β protein decreased （P<0.05）. However， co-treatment with IWR-1 markedly reversed the promoting effects of LINC02086 overexpression on the expression of M2 polarization markers， including CD206， IL⁃10， and TGF⁃β mRNA， in macrophages （P<0.05）， as well as its activation of the Wnt/β-catenin signaling pathway （P<0.05）. Compared with Vector+CM2 group， HGC-27 cells infected with OE-LINC02086+CM2 had increased proliferation activity and increased number of migration and invasion cells （P<0.05）. However， the combined intervention of IWR-1 significantly reversed the promotion of LINC02086 overexpression on the proliferation， migration and invasion of HGC-27 cells （P<0.05）. ConclusionLINC02086 overexpression promotes the proliferation， migration and invasion of gastric cancer cells by activating Wnt/β-catenin pathway to mediate M2 polarization of macrophages.

Aberrant activation of glycolysis represents a key metabolic mechanism underlying the initiation and progression of nasal inflammation. Allergic rhinitis, chronic rhinosinusitis, and vasomotor rhinitis exhibit distinct etiologies, yet all are characterized by inflammatory responses, impaired epithelial barrier function, and neurovascular dysregulation, in which glycolytic metabolic reprogramming acts as a central hub connecting immunometabolism and inflammatory regulation.Recent evidence indicates that glycolysis-dependent activation of immune cells provides the essential energy basis for inflammatory onset. In dendritic cells, eosinophils, mast cells, and Th2 cells, the expression of key glycolytic enzymes including HK2, PKM2, and LDHA is upregulated, thereby promoting cellular activation and proinflammatory cytokine release via the mTOR-HIF-1α signaling axis. Notably, the metabolic reprogramming of eosinophils prolongs their survival and enhances the release of cytotoxic granules, while in mast cells, enhanced glycolysis facilitates IgE-mediated degranulation and histamine release. Furthermore, glycolysis also influences the Th17/Treg balance, with enhanced glycolytic flux promoting Th17 differentiation and contributing to the heterogeneous inflammatory profiles observed across different rhinitis subtypes.As a central metabolite, lactate contributes to the formation of a metabolism-inflammation vicious cycle through multiple mechanisms. Lactate acidifies the local microenvironment to activate TRPV1 channels and facilitate neuropeptide release, mediates immune cell chemotaxis through GPR81, and regulates gene expression via histone lactylation, thereby sustaining proinflammatory gene transcription. These lactate-mediated processes collectively amplify local inflammation and contribute to the persistence of nasal symptoms.Glycolytic reprogramming in epithelial cells is modulated by the EGF/EGFR pathway, and its dysregulation may result in disrupted tight junctions, abnormal goblet cell hyperplasia, and subsequent tissue remodeling. Substance P and calcitonin gene-related peptide released from sensory neurons, in conjunction with metabolic products, synergistically maintain persistent inflammatory stimulation by activating mast cells, forming a neuro-immune-metabolic regulatory network that drives disease chronicity.From a therapeutic perspective, glycolytic inhibitors such as 2-deoxyglucose, FX11, and 3-bromopyruvate exert anti-inflammatory effects by targeting key enzymes including HK2 and LDHA, each with distinct mechanisms: 2-DG competitively inhibits hexokinase, FX11 selectively targets LDHA to reduce lactate production, and 3-BrPA modulates multiple glycolytic enzymes. Moreover, traditional Chinese medicine formulas, monomeric active components, and small-molecule compounds have shown promising potential in alleviating nasal inflammation by regulating the mTOR-HIF-1α axis, exerting antioxidant effects, and modulating endoplasmic reticulum stress pathways. The multi-target characteristics of these natural products offer advantages in addressing the complex pathophysiology of nasal inflammatory diseases.Despite these advances, several challenges remain. The non-selective inhibition of glycolysis may interfere with epithelial repair and mucosal regeneration, leading to delayed wound healing. Technical limitations in dynamic metabolic monitoring and sampling precision hinder the accurate assessment of local nasal metabolism. Furthermore, current animal models, which predominantly rely on acute stimulation protocols, inadequately recapitulate the chronic tissue remodeling processes characteristic of human rhinitis.This review systematically summarizes glycolysis as a common metabolic node shared by different rhinitis subtypes, offering a novel theoretical basis for the development of precision therapeutic strategies targeting metabolic reprogramming.

Aberrant activation of glycolysis represents a key metabolic mechanism underlying the initiation and progression of nasal inflammation. Allergic rhinitis, chronic rhinosinusitis, and vasomotor rhinitis exhibit distinct etiologies, yet all are characterized by inflammatory responses, impaired epithelial barrier function, and neurovascular dysregulation, in which glycolytic metabolic reprogramming acts as a central hub connecting immunometabolism and inflammatory regulation.Recent evidence indicates that glycolysis-dependent activation of immune cells provides the essential energy basis for inflammatory onset. In dendritic cells, eosinophils, mast cells, and Th2 cells, the expression of key glycolytic enzymes including HK2, PKM2, and LDHA is upregulated, thereby promoting cellular activation and proinflammatory cytokine release via the mTOR-HIF-1α signaling axis. Notably, the metabolic reprogramming of eosinophils prolongs their survival and enhances the release of cytotoxic granules, while in mast cells, enhanced glycolysis facilitates IgE-mediated degranulation and histamine release. Furthermore, glycolysis also influences the Th17/Treg balance, with enhanced glycolytic flux promoting Th17 differentiation and contributing to the heterogeneous inflammatory profiles observed across different rhinitis subtypes.As a central metabolite, lactate contributes to the formation of a metabolism-inflammation vicious cycle through multiple mechanisms. Lactate acidifies the local microenvironment to activate TRPV1 channels and facilitate neuropeptide release, mediates immune cell chemotaxis through GPR81, and regulates gene expression via histone lactylation, thereby sustaining proinflammatory gene transcription. These lactate-mediated processes collectively amplify local inflammation and contribute to the persistence of nasal symptoms.Glycolytic reprogramming in epithelial cells is modulated by the EGF/EGFR pathway, and its dysregulation may result in disrupted tight junctions, abnormal goblet cell hyperplasia, and subsequent tissue remodeling. Substance P and calcitonin gene-related peptide released from sensory neurons, in conjunction with metabolic products, synergistically maintain persistent inflammatory stimulation by activating mast cells, forming a neuro-immune-metabolic regulatory network that drives disease chronicity.From a therapeutic perspective, glycolytic inhibitors such as 2-deoxyglucose, FX11, and 3-bromopyruvate exert anti-inflammatory effects by targeting key enzymes including HK2 and LDHA, each with distinct mechanisms: 2-DG competitively inhibits hexokinase, FX11 selectively targets LDHA to reduce lactate production, and 3-BrPA modulates multiple glycolytic enzymes. Moreover, traditional Chinese medicine formulas, monomeric active components, and small-molecule compounds have shown promising potential in alleviating nasal inflammation by regulating the mTOR-HIF-1α axis, exerting antioxidant effects, and modulating endoplasmic reticulum stress pathways. The multi-target characteristics of these natural products offer advantages in addressing the complex pathophysiology of nasal inflammatory diseases.Despite these advances, several challenges remain. The non-selective inhibition of glycolysis may interfere with epithelial repair and mucosal regeneration, leading to delayed wound healing. Technical limitations in dynamic metabolic monitoring and sampling precision hinder the accurate assessment of local nasal metabolism. Furthermore, current animal models, which predominantly rely on acute stimulation protocols, inadequately recapitulate the chronic tissue remodeling processes characteristic of human rhinitis.This review systematically summarizes glycolysis as a common metabolic node shared by different rhinitis subtypes, offering a novel theoretical basis for the development of precision therapeutic strategies targeting metabolic reprogramming.

ObjectiveTranscranial focused ultrasound (tFUS) has emerged as a promising noninvasive neuromodulation technique capable of modulating neural activity with high spatial specificity. However, whether tFUS stimulation of the primary somatosensory cortex (S1) can reliably evoke conscious tactile perception without external peripheral sensory input remains unclear. Therefore, this study examined the feasibility of inducing hand-related tactile perception through targeted S1 stimulation and further investigated how sonication duration (SD), a key temporal parameter, influences the consistency of this perceptual response. The findings may provide empirical evidence for optimizing tFUS parameters in human somatosensory modulation. MethodsForty-eight healthy adults participated in the study and were assigned to two experiments. Experiment 1 included 24 participants and was designed to preliminarily examine whether S1-targeted tFUS could evoke hand-related tactile sensations. This experiment comprised two sub-experiments, Experiment 1a and Experiment 1b, with 12 participants in each. Specifically, Experiment 1a used a randomized active stimulation protocol targeting the bilateral S1 to assess the initial feasibility of inducing contralateral tactile perception, whereas Experiment 1b employed an alternating hemispheric design incorporating both active and sham stimulation to verify the specificity of the tFUS-induced sensations. Experiment 2 enrolled another 24 participants and used a real-sham dual-probe design to control for spatial tactile cues that might arise from probe-scalp contact. Five SD levels, including 200, 400, 600, 800, and 1 000 ms, were systematically tested to evaluate how stimulation duration influenced the behavioral response. The primary behavioral outcome was the perceptual consistency rate, quantified according to the accuracy of contralateral tactile localization. ResultsIn Experiment 1, 91.7% of participants reported reliable hand-related tactile sensations during active tFUS stimulation, including numbness, tingling, or similar sensory experiences. Contralateral localization accuracy under active stimulation was significantly higher than the0.50 chance level (P<0.05). In contrast, localization performance under sham stimulation did not differ from chance, suggesting that the observed tactile responses were mainly induced by active S1-targeted tFUS stimulation rather than nonspecific stimulation cues. In Experiment 2, perceptual consistency rates significantly exceeded the chance level under the 400 and 1 000 ms SD conditions(P<0.05), whereas no significant effect was observed at 200, 600, or 800 ms. Pairwise comparisons further showed that the 400 and 1 000 ms conditions produced significantly higher perceptual consistency rates than the 200 ms condition (P<0.05). ConclusiontFUS stimulation of S1 can elicit distinct hand-related tactile sensations without peripheral sensory input, demonstrating the feasibility of using targeted cortical ultrasound stimulation to induce conscious somatosensory perception. The reliability of this perceptual effect was modulated by sonication duration, indicating that temporal stimulation parameters play an important role in shaping both the occurrence and consistency of behavioral responses. Among the tested conditions, 400 ms appeared to provide a favorable temporal window for generating stable tactile perception, whereas excessively short stimulation may be insufficient to produce consistent responses. These findings highlight the sensitivity of somatosensory networks to ultrasonic modulation and provide useful parameter guidance for the application of tFUS in noninvasive sensory enhancement and cortical functional mapping.

ObjectiveMigraine is a leading neurological disorder and the fourth most common cause of years lived with disability worldwide, affecting nearly 116 million individuals. Although pharmacological treatments are available, their efficacy is often limited by side effects and variable response rates. Repetitive transcranial magnetic stimulation (rTMS) over the dorsolateral prefrontal cortex (DLPFC) offers a safe, non-invasive alternative for migraine management. However, the neurophysiological mechanisms, particularly how rTMS modulates local cortical excitability and distributed pain-related circuits, remain poorly understood. Elucidating these mechanisms is essential for optimizing treatment protocols and improving clinical outcomes. MethodsThis study employed concurrent transcranial magnetic stimulation and electroencephalography (TMS-EEG) to investigate neuroplastic and neurocircuitry mechanisms of DLPFC-rTMS in migraine. Study 1 compared 30 migraineurs and 28 healthy controls to identify abnormalities in TMS-evoked potentials (TEPs) and significant current density (SCD) within sensory-discriminative regions including the primary somatosensory cortex (S1) and posterior insula (pINS), cognitive-affective regions including the anterior insula (aINS) and midcingulate cortex (MCC), and a descending modulatory region, the periaqueductal gray (PAG). Study 2 used a single-blind, crossover, sham-controlled design in 34 healthy participants. Each participant received both active (10 Hz, 80% RMT, 1 500 pulses) and sham DLPFC-rTMS in counterbalanced order. TMS-EEG and cold pain tolerance were assessed before and after each session. ResultsIn Study 1, migraineurs showed a significantly less negative N120 amplitude compared to healthy controls (P=0.027, Cohen’s d=0.60), indicating local intracortical disinhibition. No group differences were observed for N40, P60, or P180 components. At the source level, migraineurs exhibited significantly higher SCD in the S1, pINS, aINS, and MCC (allQ<0.05), but not in the ventroposterior thalamus (vpTHAL), mediodorsal thalamus (mdTHAL), or PAG. In Study 2, active rTMS significantly reduced SCD from pre- to post-stimulation in the S1, aINS, and MCC (all Q<0.05). Sham stimulation also reduced SCD in the S1 (Q<0.05) but not in the aINS or MCC. Although no significant group-level analgesic effect was observed between active and sham conditions (P=0.107), correlation analyses revealed that greater SCD reductions in the S1 and MCC were significantly associated with higher post-rTMS pain tolerance (R=-0.487 and -0.495, both Q<0.01) and larger improvements in pain tolerance(R=-0.487 and -0.451, both Q<0.05). No such correlations were found following sham stimulation, suggesting that the behavioural relevance of neural changes is specific to active rTMS. ConclusionThis study provides novel evidence that migraineurs exhibit both local neuroplastic abnormalities (reduced N120 amplitude) and hyperactivity in key pain-processing regions (S1, pINS, aINS, MCC). A single session of DLPFC-rTMS reduced hyperactivity in the aINS, MCC, and S1. Notably, greater reductions in the S1 and MCC were associated with improved pain tolerance. These findings identify distinct cortical circuitries, particularly within the cognitive-affective pain network, that may serve as potential biomarkers for optimizing rTMS treatment in migraine and other chronic pain conditions. Future studies should validate these results in patient populations experiencing spontaneous migraine attacks and explore multi-session or accelerated rTMS protocols.

Steroid-associated osteonecrosis of the femoral head (SANFH) is a progressive osteoarticular disorder associated with prolonged or high-dose glucocorticoid exposure. Its development involves local ischemia, oxidative stress, dysregulated bone metabolism, and disruption of the osteoimmune microenvironment. Macrophages exhibit marked phenotypic plasticity, and their polarization is essential for maintaining the dynamic balance among inflammation, angiogenesis, and bone remodeling. Persistent glucocorticoid stimulation, hypoxia, excessive reactive oxygen species, and damage-associated signals released from necrotic tissues can shift macrophages toward a pro-inflammatory phenotype. Classically activated macrophages (M1 macrophages) predominantly mediate inflammatory responses. By releasing tumor necrosis factor-α, interleukin-1β, interleukin-6, and other mediators, promoting osteoclast activation, suppressing the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), and impairing vascular endothelial function, M1 macrophages accelerate trabecular destruction and expansion of the necrotic lesion. In contrast, alternatively activated macrophages (M2 macrophages) contribute to inflammation resolution, neovascularization, osteogenic repair, and tissue remodeling, thereby supporting regeneration within the necrotic region. Macrophage-derived exosomes further influence disease progression through intercellular communication. Exosomes from different macrophage phenotypes can differentially regulate adipogenic differentiation, neutrophil extracellular trap formation, and endothelial phenotypic transition, thereby affecting the repair capacity of the necrotic area. These findings indicate that macrophage polarization shapes the local microenvironment not only through soluble mediators but also through vesicle-mediated communication with BMSCs, neutrophils, endothelial cells, and other cell populations. At the molecular level, the nucleotide-binding domain leucine-rich repeat and pyrin domain-containing receptor 3(NLRP3) inflammasome, nuclear factor kappa B (NF‑κB), Janus kinase/signal transducer and activator of transcription (JAK/STAT), and phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) pathways jointly regulate macrophage polarization and its downstream osteoimmune effects. Dysregulation of these pathways may sustain inflammatory activation, aggravate oxidative and vascular injury, inhibit osteogenesis, and impair tissue repair. NLRP3 inflammasome activation links danger signals and oxidative stress to inflammatory cytokine maturation and pyroptotic injury; NF-κB signaling promotes pro-inflammatory gene transcription and M1 polarization; JAK/STAT signaling participates in the balance between inflammatory and reparative macrophage programs; and PI3K/Akt/mTOR signaling regulates cellular metabolism, survival, autophagy, and regeneration. Notably, the biological effects of PI3K/Akt/mTOR signaling are cell-type dependent, and Akt-mediated repair signaling should be distinguished from mTOR-related autophagy regulation. The pathological significance of macrophage polarization in SANFH is not determined simply by an increase or decrease in a single phenotype. Rather, disease progression appears to result from an imbalance between persistent pro-inflammatory activity and insufficient reparative responses at different stages of the disease. Such an imbalance disrupts the coordinated coupling of inflammation resolution, vascular regeneration, and bone remodeling, ultimately contributing to structural deterioration of the femoral head. This review summarizes the pathological roles, signaling regulation, and exosome-mediated intercellular communication associated with macrophage polarization imbalance in SANFH. A more precise understanding of these mechanisms may clarify the osteoimmune basis of SANFH and support the development of macrophage-targeted interventions. However, most available evidence is derived from cellular and animal studies, and the temporal evolution of macrophage phenotypes in patients remains insufficiently characterized. Therapeutic strategies should therefore move beyond the simple suppression of M1 macrophages or enhancement of M2 macrophages and instead aim to restore a stage-appropriate balance between inflammatory control and tissue repair while promoting angiogenesis and bone reconstruction.

ObjectiveOxygen partial pressure (pO₂) is a critical indicator of the tumor microenvironment and plays an essential role in regulating tumor progression and therapeutic response, particularly for oxygen-dependent treatments such as photodynamic therapy (PDT). Although photoacoustic imaging (PAI) has shown great potential for functional and molecular imaging, conventional oxygenation imaging approaches based on hemoglobin absorption mainly provide relative oxygen saturation information and cannot directly quantify tissue oxygen partial pressure. Therefore, this study aimed to develop a fast laser sequence-based pump-probe photoacoustic tomography (PP-PAT) system for quantitative, non-invasive, and dynamic monitoring of oxygen partial pressure in tumor tissues. MethodsThe proposed PP-PAT system was developed based on the oxygen-sensitive triplet-state lifetime characteristics of methylene blue (MB). Upon optical excitation, MB molecules undergo transitions from the ground state to an excited state and subsequently form metastable triplet states through intersystem crossing. The lifetime of the triplet state is strongly affected by surrounding oxygen concentration due to dynamic oxygen quenching, providing a direct correlation between triplet-state kinetics and local oxygen partial pressure. A dual-wavelength pump-probe excitation scheme was implemented to selectively interrogate MB triplet-state dynamics. The pump pulse was used to initiate the triplet-state population, while the delayed probe pulse was applied to detect the transient triplet-state response. By optimizing the temporal interval between the pump and probe pulses, transient triplet-state differential (TTD) signals were extracted to enhance the specificity of oxygen-dependent molecular information and suppress background interference from conventional photoacoustic signals. The performance of the PP-PAT system was systematically evaluated through phantom and in vivo experiments. First, a single-tube phantom containing MB solution was used to investigate signal stability, reproducibility, and the influence of signal averaging on imaging quality. Subsequently, a dual-tube phantom model was established to simulate oxygen consumption during PDT, where one MB-containing tube was exposed to laser irradiation and the other served as a control. Finally, in vivo experiments were performed using a subcutaneous tumor model in nude mice. MB was locally injected into the tumor region before imaging to evaluate the feasibility of tumor oxygen partial pressure mapping using the proposed PP-PAT system. ResultsPhantom experiments demonstrated that the extracted TTD signals exhibited high stability and effectively reflected MB triplet-state dynamics while reducing non-specific background contributions. Signal averaging significantly improved the signal-to-noise ratio, and 50 repeated acquisitions provided an optimal compromise between image quality and acquisition efficiency. In the dual-tube phantom experiments, continuous PDT irradiation induced progressive oxygen depletion in the treated sample. The corresponding TTD decay rate gradually decreased, accompanied by an increase in the calculated triplet-state lifetime, indicating reduced oxygen quenching and decreased oxygen partial pressure. In contrast, the control sample showed relatively stable TTD kinetics and oxygenation levels during the same period. These results demonstrated that PP-PAT could quantitatively characterize oxygen consumption dynamics associated with photochemical reactions. In vivo experiments further demonstrated the capability of PP-PAT for spatially resolved oxygen partial pressure imaging in MB-injected tumor tissues. The reconstructed pO₂ maps revealed heterogeneous oxygen distributions within tumors, showing relatively hypoxic regions in the tumor core and higher oxygenation levels near the tumor boundary. This spatial oxygen distribution pattern was consistent with the typical physiological characteristics of solid tumors, where abnormal vascular structures and limited oxygen diffusion result in intratumoral oxygen gradients. ConclusionThis study presents a fast laser sequence-based PP-PAT system capable of quantitative and non-invasive imaging of tissue oxygen partial pressure. By utilizing the oxygen-dependent triplet-state lifetime of MB and extracting TTD signals, the proposed method provides molecularly specific information related to oxygen dynamics beyond conventional photoacoustic oxygenation imaging. The system enables dynamic monitoring of oxygen consumption during PDT and reveals spatial oxygen heterogeneity within tumors. This technique provides a promising imaging approach for tumor hypoxia characterization, evaluation of oxygen-dependent therapeutic responses, and precision-guided cancer treatment.

ObjectivePhotoacoustic pump-probe imaging can effectively eliminate the interference of blood background signal in traditional photoacoustic imaging, and realize the imaging of weak phosphorescence molecules and their triplet lifetimes in deep tissues. However, background differential noise in photoacoustic pump-probe imaging often leads to large fitting results of phosphorescent molecule concentration and triplet lifetime. Therefore, this paper proposes a novel triplet lifetime fitting method for photoacoustic pump-probe imaging. By extracting the phase of the triplet differential signal and the background noise, the fitting bias caused by the background noise can be effectively corrected. MethodsThe advantages and feasibility of the proposed algorithm are verified by numerical simulation, phantom and in vivo experiments, respectively. ResultsIn the numerical simulation, under the condition of noise intensity being 10% of the signal amplitude, the new method can optimize the fitting deviation from 48.5% to about 5%, and has a higher exclusion coefficient (0.88>0.79), which greatly improves the fitting accuracy. The high specificity imaging ability of photoacoustic pump imaging for phosphorescent molecules has been demonstrated by phantom experiments. In vivo experiments have verified the feasibility of the new fitting method proposed in this paper for fitting phosphoometric lifetime to monitor oxygen partial pressure content during photodynamic therapy of tumors in nude mice. ConclusionThis work will play an important role in promoting the application of photoacoustic pump-probe imaging in biomedicine.