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Zezhong Li - IEEE Xplore Author Profile

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The global increase in lung cancer cases, often marked by pulmonary nodules, underscores the critical importance of timely detection to mitigate cancer progression and reduce morbidity and mortality. The Faster R-CNN approach is a two-stage, high-precision nodule detection method designed for detecting small nodules, particularly in computed tomography (CT) images. This paper presents an improved ...Show More
The efficiency of state-of-the-art convolutional networks trained to detect lung cancer nodules depends on their feature extraction model. Various feature extraction models have been proposed based on convolutional networks, such as VGG-Net, or ResNet. It has been demonstrated that such models effectively extract features from objects in an image. However, their efficacy is limited when the object...Show More
Objective: Cardiac gating, synchronizing medical scans with cardiac activity, is widely used to make quantitative measurements of physiological events and to obtain high-quality scans free of pulsatile artefacts. This can provide important information for disease diagnosis, targeted control of medical microrobots, etc. The current work proposes a low-cost, self-adaptive, MRI-compatible cardiac gat...Show More
Objective: Superparamagnetic nanoparticles (SPIONs) can be combined with tumor chemoembolization agents to form magnetic drug-eluting beads (MDEBs), which are navigated magnetically in the MRI scanner through the vascular system. We aim to develop a method to accurately quantify and localize these particles and to validate the method in phantoms and swine models. Methods: MDEBs were made of Fe3O4 ...Show More
Dipole field navigation (DFN) is a method that has been developed to deliver therapeutics toward tumoral regions by navigating microcarriers in the vascular network. To do so, DFN distorts the high uniform magnetic field of a clinical magnetic resonance imaging (MRI) scanner using precisely located ferromagnetic balls to create magnetic gradients to implement the directional forces required to nav...Show More
This paper presents a CMOS optoelectronic lock-in amplifier (LIA) with semi-digital automatic phase alignment for optical sensing applications. The LIA incorporates a phase sensitive detection (PSD) channel and a phase alignment channel. A phase alignment loop generates the LIA reference clock, and automatically aligns the relative phase between the reference and the input signal through a phase i...Show More
Accurately resolving small fluorescence power variations in presence of noise and high-background tissue autofluorescence from deep brain structures with a fiber photometry system requires highly linear and sensitive photo detectors. This paper presents a high-dynamic range (DR) CMOS biosensor fusing a low-noise photosensing front-end with a high-precision extended counting analog-to-digital conve...Show More
Objective: Dipole field navigation and magnetic resonance navigation exploit B0 magnetic fields and imaging gradients for targeted intra-arterial therapies by using magnetic drug-eluting beads (MDEBs). The strong magnetic strength (1.5 or 3 T) of clinical magnetic resonance imaging (MRI) scanners is the main challenge preventing the formation and controlled injection of specific-sized particle agg...Show More
This paper presents a high-dynamic range CMOS biosensor fusing a photosensing module with a high-precision extended counting analog-to-digital converter (ADC) with noise cancellation to detect florescence neural signal fluctuations of very low incident power. The 7 MSBs are resolved by a first order continuous-time resettable ΣΔ ADC, whereas the residue voltage is quantized by a 10-bit single slop...Show More
This paper presents an optoelectronic neuroscience platform for monitoring neural dynamics in intact deep brain structures. A wireless optoelectronic headstage incorporating all aspects of a conventional benchtop high-performance optical fiber photometry system is presented to detect fluorescence signal fluctuations in the brain of live animal models. The headstage includes a photosensor, a fiber ...Show More
Fluorescence biophotometry measurements require wide dynamic range (DR) and high-sensitivity laboratory apparatus. Indeed, it is often very challenging to accurately resolve the small fluorescence variations in presence of noise and highbackground tissue autofluorescence. There is a great need for smaller detectors combining high linearity, high sensitivity, and high-energy efficiency. This paper ...Show More
Implantable wireless fiber biophotometry is one of the most effective technique to monitor specific cell types through Ca2+ fluorescence sensing in live animals by avoiding fiber tethering and risks of breakage and injury which can occur in conventional apparatus. This demonstration will show the visitors a novel low-power, light-weight, and minimally invasive wireless optoelectronic interface ena...Show More
This paper presents a high-sensitivity incremental discrete time ΣΔ analog-to-digital converter (ADC) with variable clock and on-chip decimation for biophotometry sensing. A digital correlated double sampling (CDS) scheme is merged with the decimation filter for providing energy- and area-efficient mean to suppress low-frequency noise. Chopper modulation and differential sensing using a dummy phot...Show More
Magnetically guided agents in the vascular network are expected to enable the targeted delivery of therapeutics to localized regions while avoiding their systemic circulation. Due to the small size of the medically applicable superparamagnetic microscale agents required to reach the smaller arteries, high magnetic fields and gradients are required to reach saturation magnetization and generate suf...Show More
This paper presents a new biophotometry sensor embedding two individual building blocks, namely a low-noise sensing front-end and a 2nd order continuous-time ΣΔ modulator (CTSDM), into a single module for enabling high-sensitivity and high energy-efficiency photo-sensing. In particular, a differential CMOS photodetector associated with a differential capacitive transimpedance amplifier (DCTIA)-bas...Show More
Fluorescence biophotometry measurements require wide dynamic range (DR) and high sensitivity laboratory apparatus. Indeed, it is often very challenging to accurately resolve the small fluorescence variations in presence of high background tissue autofluorescence. There is a great need for smaller detectors combining high linearity, high sensitivity, and high-energy efficiency. This paper presents ...Show More
Dipole Field Navigation (DFN) has been proposed previously as a promising remote magnetic actuation method for the navigation of microscale agents in vascular networks for the targeted delivery of therapeutics. This method exploits the strong magnetic field of a magnetic resonance imaging scanner to bring the agents at saturation magnetization, and relies on the proper positioning of ferromagnetic...Show More
MC-1 strain magneto-aerotactic bacteria recently used in cancer therapy and labeled with superparamagnetic nanoparticles are localized by magnetic particle imaging (MPI) spectrometry. A 8.5 mT drive field oscillating at 150 kHz is generated in a solenoid coil and placed near two receiving coils connected in series in a gradiometric configuration. The magnetic behavior of superparamagnetic particle...Show More
Targeted drug delivery through the use of swimming microorganisms known as Magnetococcus marinus MC-1 magnetotactic bacteria (or MTB) [1] acting as nanorobots loaded with therapeutic agents has been demonstrated [2]. While the role of magnetic nanoparticles (MNPs) in medicine and more specifically drug delivery enhancement is generally known [3], this study aims to couple the previously mentioned ...Show More
A recently introduced method for robotic vascular catheterization is Fringe Field Navigation (FFN). A requirement of this method is the trajectory required for planning the sequences of navigation. We have introduced a method of trajectory planning compatible with the requirements of FFN for vasculature navigation. The method exploits the vessel centerline to define the vascular structure trajecto...Show More
In this paper, a method based on an oscillating flow consisting of an 8 Hz vibrating flow and a constant flow used to increase the manipulation capability of particles in liquid is developed and demonstrated. The method was integrated with magnetic resonance navigation (MRN) for targeted manipulation. Micro particles encapsulating superparamagnetic nanoparticles were successfully navigated in a Y-...Show More
Intravenous systemic injection of fluidMAG-PMO magnetic nanoparticles followed by hyperthermia of the brain has previously shown to be a promising method for overcoming the blood-brain barrier; the great challenge of drug delivery to the brain. This study explores the possibility of utilizing magnetotactic bacteria as micro-carriers for fluidMAG-ARA magnetic nanoparticles as means of direct target...Show More
A new low-power custom integrated lock-in amplifier (LIA) with semi-digital automatic phase tuning is presented. The proposed LIA leverages a new semi-digital phase tuning peripheral loop to automatically align the relative phase of a low-amplitude input signal of known carrier with that of a reference signal to increase sensitivity while decreasing the power consumption of the LIA compared with p...Show More
This paper tackles the inverse problem of finding optimal configurations of magnetic gradient sources in Dipole Field Navigation (DFN), a magnetic navigation method proposed recently for the direct targeting of drugs. In DFN, a limited number of these gradient sources, called the cores, must be positioned properly around a patient in a Magnetic Resonance Imaging scanner to induce the required dire...Show More
Fringe Field Navigation (FFN), a method first introduced by our group, aims at providing a high directional pulling force on a magnetic object such as a magnetic tip of a guidewire or other instruments. In a clinical setting, the pulling force is typically produced by the strong fringe field generated by the superconducting magnet of a clinical Magnetic Resonance Imaging (MRI) scanner. Because it ...Show More