Li Qi

Li Qi
Southern Medical University | FIMMU · School of Biomedical Engineering

Ph. D.

About

74
Publications
6,077
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720
Citations
Introduction
南方医科大学 戚力;OCT and PAT. Please visit my lab website: https://smu-iotlab.github.io/

Publications

Publications (74)
Article
Full-text available
Radiotherapy, a traditional cancer treatment, not only controls local tumor growth but also potentially induces immunogenic cell death, initiating systemic immune responses. However, radiotherapy resistance and immunosuppressive tumor microenvironments often limit the potency of radiation‐induced anti‐tumor immune responses, rendering them insuffic...
Article
Full-text available
Multispectral photoacoustic tomography (PAT) is an imaging modality that utilizes the photoacoustic effect to achieve non-invasive and high-contrast imaging of internal tissues but also molecular functional information derived from multi-spectral measurements. However, the hardware cost and computational demand of a multispectral PAT system consist...
Preprint
Photoacoustic tomography (PAT) enables non-invasive cross-sectional imaging of biological tissues, but it fails to map the spatial variation of speed-of-sound (SOS) within tissues. While SOS is intimately linked to density and elastic modulus of tissues, the imaging of SOS distri-bution serves as a complementary imaging modality to PAT. Moreover, a...
Preprint
Photoacoustic tomography (PAT) offers optical contrast, whereas magnetic resonance imaging (MRI) excels in imaging soft tissue and organ anatomy. The fusion of PAT with MRI holds promising application prospects due to their complementary advantages. Existing image fusion have made considerable progress in pre-registered images, yet spatial deformat...
Article
In photoacoustic tomography (PAT), acoustic inversion aims to recover the spatial distribution of light energy deposition within the imaging object from the signals captured by detectors. To achieve quantitative imaging, optical inversion is further employed to derive absorption coefficient (AC) images. However, limitations such as restricted detec...
Article
Full-text available
Photoacoustic tomography (PAT), as a novel medical imaging technology, provides structural, functional, and metabolism information of biological tissue in vivo. Sparse Sampling PAT, or SS-PAT, generates images with a smaller number of detectors, yet its image reconstruction is inherently ill-posed. Model-based methods are the state-of-the-art metho...
Article
This paper presents a novel method based on leveraging physics-informed neural networks for magnetic resonance electrical property tomography (MREPT). MREPT is a noninvasive technique that can retrieve the spatial distribution of electrical properties (EPs) of scanned tissues from measured transmit radiofrequency (RF) in magnetic resonance imaging...
Article
Full-text available
Immunotherapy has emerged as an innovative strategy with the potential to improve outcomes in cancer patients. Recent evidence indicates that radiation‐induced DNA damage can activate the cyclic‐GMP‐AMP synthase (cGAS)‐stimulator of interferon genes (STING) pathway to enhance the antitumor immune response. Even so, only a small fraction of patients...
Article
Full-text available
Photoacoustic tomography (PAT) is a promising imaging technique that can visualize the distribution of chromophores within biological tissue. However, the accuracy of PAT imaging is compromised by light fluence (LF), which hinders the quantification of light absorbers. Currently, model-based iterative methods are used for LF correction, but they re...
Article
Photoacoustic tomography (PAT) and magnetic resonance imaging (MRI) are two advanced imaging techniques widely used in pre-clinical research. PAT has high optical contrast and deep imaging range but poor soft tissue contrast, whereas MRI provides excellent soft tissue information but poor temporal resolution. Despite recent advances in medical imag...
Chapter
Autofocusing is essential and serves as a prerequisite for the automation of embryo biopsy in preimplantation genetic testing (PGT) using robotics. Despite the existence of numerous autofocus algorithms, achieving accurate autofocusing for cleavage-stage embryos in brightfield microscopy remains challenging due to their non-unimodal nature. Thus, a...
Article
Full-text available
Endoscopic airway optical coherence tomography (OCT) is a non-invasive and high resolution imaging modality for the diagnosis and analysis of airway-related diseases. During OCT imaging of the upper airway, in order to reliably characterize its 3D structure, there is a need to automatically detect the airway lumen contour, correct rotational distor...
Article
Full-text available
Photoacoustic tomography (PAT) images contain inherent distortions due to the imaging system and heterogeneous tissue properties. Improving image quality requires the removal of these system distortions. While model-based approaches and data-driven techniques have been proposed for PAT image restoration, achieving accurate and robust image recovery...
Article
Full-text available
Photoacoustic tomography (PAT) is a promising imaging technique that utilizes the detection of light-induced acoustic waves for both morphological and functional biomedical imaging. However, producing high-quality images using PAT is still challenging and requires further research. Besides improving image reconstruction, which turns the raw photoac...
Article
Magnetic resonance imaging (MRI) and photoacoustic tomography (PAT) offer two distinct image contrasts. To integrate these two modalities, we present a comprehensive hardware-software solution for the successive acquisition and co-registration of PAT and MRI images in in vivo animal studies. Based on commercial PAT and MRI scanners, our solution in...
Article
Full-text available
Introduction The high concentration of glutathione (GSH) and hydrogen peroxide (H2O2) levels within the tumor microenvironment (TME) are the major obstacle to induce the unsatisfactory anticancer treatment efficiency. The synergistic cancer therapy strategies of the combination the GSH depletion enhanced chemodynamic therapy (CDT) with photothermal...
Article
Although radiotherapeutic efficiency has been revealed to be positively correlated with ferroptosis, the neutral/alkaline cytoplasm pH value of tumor cells remains an intrinsic challenge for efficient Fenton/Fenton-like reaction-based ferroptosis induction. Herein, PEGylated hollow mesoporous organosilica nanotheranostics (HMON)-GOx@MnO2 nanopartic...
Article
Radiotherapy (RT) mediated tumor immunogenicity offers an opportunity for simultaneous RT and immunotherapy via immunogenic cell death (ICD), which releases damaged-associated molecular patterns and generates “eat me” signals for the innate immune system to modulate the immunogenicity. However, tumor hypoxia significantly reduces the therapeutic ef...
Article
Full-text available
In Photoacoustic Tomography (PAT), the acquired image represents a light energy deposition map of the imaging object. For quantitative imaging, the PAT image is converted into an absorption coefficient (μa) map by dividing the light fluence (LF). Previous methods usually assume a uniform tissue μa distribution, and consequently degrade the LF corre...
Article
Though amounts of attempts about nanomedicine for chemo-radiotherapy have been made, more efficient strategies for chemo-radio therapy enhancement still need to be studied and perfected. Herein, a 'yolk-shell'-like nanostructure (Bi2S3@mBixMnyOz nanosystem) was facilely constructed by directly using radiosensitizer Bi2S3 nanorods (NRs) as a partial...
Article
As an emerging molecular imaging modality, Photoacoustic Tomography (PAT) is capable of mapping tissue physiological metabolism and exogenous contrast agent information with high specificity. Due to its ultrasonic detection mechanism, the precise localization of targeted lesions has long been a challenge for PAT imaging. The poor soft-tissue contra...
Article
Full-text available
Background Radiotherapy (RT) is clinically well-established cancer treatment. However, radioresistance remains a significant issue associated with failure of RT. Phototherapy-induced radiosensitization has recently attracted attention in translational cancer research. Methods Cu-Sb-S nanoparticles (NPs) coated with ultra-small Au nanocrystals (Au@...
Article
Full-text available
Glutathione (GSH) is an important biological thiol in cells, which is involved in many physiological processes in the organism and regulates pathological processes of cells. Rapid and accurate monitoring of GSH in vitro and in vivo is quite needed in investigating important biochemical events. In this contribution, innovative cerium (Ce) doped poly...
Article
Full-text available
Background Combining the multimodal imaging and synergistic treatment in one platform can enhance the therapeutic efficacy and diagnosis accuracy. Results In this contribution, innovative Mn-doped Prussian blue nanoparticles (MnPB NPs) were prepared via microemulsion method. MnPB NPs demonstrated excellent T 1 and T 2 weighted magnetic resonance i...
Preprint
Full-text available
Background High resolution, strong contrast and multimodality visualization of live mammalian embryo is an important requirement for studying foetal development. Photoacoustic Tomography (PAT) and Optical Coherence Tomography (OCT) are two advanced imaging modalities that has been utilized for embryonic imaging. However, high contrast, multiscale a...
Article
Full-text available
Endoscopic airway optical coherence tomography (OCT) is an advanced imaging modality capable of capturing the internal anatomy and geometry of the airway. Due to fiber-optic catheter bending and friction, the rotation speed of the endoscopic probe is usually non-uniform: at each B-scan image, the initial rotation angle of the probe is easily misali...
Article
Preclinical imaging with photoacoustic tomography (PAT) has attracted wide attention in recent years since it is capable of providing molecular contrast with deep imaging depth. The automatic extraction and segmentation of the animal in PAT images is crucial for improving image analysis efficiency and enabling advanced image post-processing, such a...
Article
Background and objective Photoacoustic tomography (PAT) is capable of obtaining cross-sectional images of small animals that represent the optical absorption of biological tissues. The multispectral Interlaced Sparse Sampling PAT, or ISS-PAT, is a previously proposed PAT imaging method that offered high quality images with much sparser transducer a...
Article
Full-text available
Numerous techniques have been demonstrated for effective generation of orbital angular momentum-carrying radiation, but intracavity generation of continuously tunable pulses in the femtosecond regime remains challenging. Even if such a creation was realized, the generated pulses—like all pulses in reality—are complex and transitory objects that can...
Article
The spatial resolution of photoacoustic tomography (PAT) can be characterized by the point spread function (PSF) of the imaging system. Due to the tomographic detection geometry, the PAT image degradation model could be generally described by using spatially variant PSFs. Deconvolution of the PAT image with these PSFs could restore image resolution...
Preprint
Magnetic resonance imaging (MRI) and photoacoustic tomography (PAT) are two advanced imaging modalities that offer two distinct image contrasts: MRI has a multi-parameter contrast mechanism that provides excellent anatomical soft tissue contrast, whereas PAT is capable of mapping tissue physiological metabolism and exogenous contrast agents with op...
Article
Full-text available
Electrical properties provide essential information for cancer detection and specific absorption rate (SAR) estimation. Magnetic resonance electrical properties tomography (MREPT) is an approach to retrieve the distribution of electrical properties. The conventional method suffers from the locally homogeneous assumption and amplification of noise....
Article
Background and objective: In acoustic inversion of photoacoustic tomography (PAT), an imaging model that precisely describes both the ultrasonic wave propagation and the detector properties is of crucial importance. Inspired by the multi-stripe integration model in clinical X-ray computed tomography systems, in this work, we introduce the Multi-Cu...
Article
Multispectral photoacoustic tomography (PAT) is capable of resolving tissue chromophore distribution based on spectral un-mixing. It works by identifying the absorption spectrum variations from a sequence of photoacoustic images acquired at multiple illumination wavelengths. Due to multispectral acquisition, this inevitably creates a large dataset....
Article
Purpose: This study aims to develop and evaluate a robust conductivity imaging method that combines total variation and wavelet regularization to enhance the accuracy of conductivity maps. Theory and methods: The proposed approach is based on a gradient-based method. The central equation is derived from Maxwell's equation and describes the relat...
Preprint
Structured ultrafast optical pulses provide multiple degrees of freedom for laser physics and practical applications. The comprehensive and vectorial characterizations of the structured light is, therefore, fundamental because of its relevance in several scientific and technological fields. In this work, we implement and demonstrate the vectorial i...
Article
There is a growing recognition regarding the importance of pial collateral flow in the protection from impending ischemic stroke both in preclinical and clinical studies. Collateral flow is also a major player in sensory stimulation-based protection from impending ischemic stroke. Doppler optical coherence tomography has been employed to image spat...
Preprint
Full-text available
Numerous techniques have been demonstrated for effective generation of orbital angular momentum-carrying radiation, but intracavity generation of continuously tunable pulses in the femtosecond regime remains challenging. Even if such a creation was realized, the generated pulses, like all pulses in reality, are complex and transitory objects that c...
Article
Full-text available
One of the advantages of photoacoustic imaging (PAI) is that its image contrast may come from exogenous agents. Such advantage leads to the development of a great number of exogenous probes. However, the biosafety of most of these contrast agents has not yet been confirmed, thus hindering their clinical translation. In this work, we report on the u...
Article
Full-text available
Subglottic stenosis (SGS) is a challenging disease to diagnose in neonates. Long-range optical coherence tomography (OCT) is an optical imaging modality that has been described to image the subglottis in intubated neonates. A major challenge associated with OCT imaging is the lack of an automated method for image analysis and micrometry of large vo...
Article
Full-text available
Subglottic stenosis (SGS) is a challenging disease to diagnose in neonates. Long-range optical coherence tomography (OCT) is an optical imaging modality that has been described to image the subglottis in intubated neonates. A major challenge associated with OCT imaging is the lack of an automated method for image analysis and micrometry of large vo...
Article
Mitochondria are essential organelles in eukaryotic cells and act as the energy powerhouse and biosynthetic compartment. Fluorescent dyes are widely used powerful molecular tools for analytical sensing and optical imaging. Low photostability, short excitation and emission wavelengths, and aggregation-induced quenching effects restrict the applicati...
Article
Full-text available
Optoacoustic tomography (OAT) is an emerging imaging modality with ultrasonic imaging depth and optical contrast. The reconstruction of optoacoustic image is to recover the initial acoustic pressure distribution of the object from a set of ultrasound signals. The model-based optoacoustic tomography image reconstruction is an ill-conditioned inverse...
Article
Near-infrared absorption chromophore has broad prospects as a photoacoustic imaging/photothermal agent due to its simple chemical structure, high purity and good biocompatibility. But their development is severely limited due to low photothermal conversion efficiency and photothermal instability. Hence, a donor-acceptor chromophore containing the 2...
Article
Full-text available
Automatic delineation and segmentation of airway structures from endoscopic optical coherence tomography (OCT) images improve image analysis efficiency and thus has been of particular interest. Conventional two-dimensional automatic segmentation methods, such as the dynamic programming approach, ensures the edge-continuity in the xz-direction (intr...
Article
Full-text available
Incorporating different data processing methods, optical coherence tomography (OCT) has the ability for high-resolution angiography and quantitative flow velocity measurements. However, OCT angiography cannot provide quantitative information of flow velocities, and the velocity measurement based on Doppler OCT requires the determination of Doppler...
Article
Shear wave measurements for the determination of tissue elastic properties have been used in clinical diagnosis and soft tissue assessment. A shear wave propagates as a transverse wave where vibration is perpendicular to the wave propagation direction. Previous transverse shear wave measurements could detect the shear modulus in the lateral region...
Conference Paper
Shear wave measurement enables quantitative assessment of tissue viscoelasticity. In previous studies, a transverse shear wave was measured using optical coherence elastography (OCE), which gives poor resolution along the force direction because the shear wave propagates perpendicular to the applied force. In this study, for the first time to our k...
Article
Full-text available
Elastography provides a powerful tool for histopathological identification and clinical diagnosis based on information from tissue stiffness. Benefiting from high resolution, three-dimensional (3D), and noninvasive optical coherence tomography (OCT), optical micro-elastography has the ability to determine elastic properties with a resolution of ~10...
Conference Paper
Optical coherence tomography (OCT) is a noninvasive method for retinal imaging. In this work, we present an in vivo human retinal microvascular network measurement by an intensity-based Doppler variance (IBDV) based on sweptsource OCT. In addition, an automatic three-dimensional (3-D) segmentation method was used for segmenting intraretinal layers....
Article
Full-text available
Doppler optical coherence tomography (DOCT) is considered one of the most promising functional imaging modalities for neuro biology research and has demonstrated the ability to quantify cerebral blood flow velocity at a high accuracy. However, the measurement of total absolute blood flow velocity (BFV) of major cerebral arteries is still a difficul...
Article
Full-text available
We present an automatic segmentation method for the delineation and quantitative thickness measurement of multiple layers in endoscopic airway optical coherence tomography (OCT) images. The boundaries of the mucosa and the sub-mucosa layers are accurately extracted using a graph-theory-based dynamic programming algorithm. The algorithm was tested w...
Article
The quality inspection process is usually carried out after first processing of the raw materials such as cutting and milling. This is because the parts of the materials to be used are unidentified until they have been trimmed. If the quality of the material is assessed before the laser process, then the energy and efforts wasted on defected materi...
Article
Irregular shape objects with different 3-dimensional (3D) appearances are difficult to be shaped into customized uniform pattern by current laser machining approaches. A laser galvanometric scanning system (LGS) could be a potential candidate since it can easily achieve path-adjustable laser shaping. However, without knowing the actual 3D topograph...
Article
The true random number generator (TRNG) is an invaluable resource for many applications. Present TRNG methods all require specialised and expensive hardware, which are not suitable for personal use. A portable TRNG configuration is proposed, which is simply based on the camera of a commercial smartphone. No other auxiliary equipment except the mobi...
Article
Full-text available
Triangulation laser range scanning, which has been wildly used in various applications, can reconstruct the 3D geometric of the object with high precision by processing the image of laser stripe. The unbiased line extractor proposed by Steger is one of the most commonly used algorithms in laser stripe center extraction for its precision and robustn...
Article
The calibration of a structured light plane is the key technique in structured light 3D vision measurement. In this paper, a novel method of structured light plane calibration is presented. A simple 2D planar target is used, which can be freely moved to different positions in the visible space of a camera when the target and the structured light pl...
Article
Stereo vision based 3D metrology technique is an effective approach for relatively large scale object's 3D geometric detection. In this paper, we present a specified image capture system, which implements LVDS interface embedded CMOS sensor and CAN bus to ensure synchronous trigger and exposure. We made an error analysis for structured light vision...

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