School of Biomedical Engineering

Comprehensive Dataset of 72 Electro-deposited ZnO Nanostructured Sensors for Acetone Detection in E-Nose Applications

2026-04-29T00:00:00Z

Comprehensive Dataset of 72 Electro-deposited ZnO Nanostructured Sensors for Acetone Detection in E-Nose Applications Garay-Rairan, Fabian; Wang, Qi; Tricoli, Antonio; Qian, Jing; Lensky, Artem; Murugappan, Krishnan; Suominen, Hanna This dataset presents a comprehensive experimental study of 72 individual zinc oxide (ZnO) nanostructured sensors designed for electronic nose (E-Nose) applications, specifically targeting high-sensitivity acetone detection. The sensors were fabricated using an optimized electrodeposition process, where three key manufacturing parameters were systematically varied: ZnCl₂ molarity (0.01M to 0.2M), current density (-100µA to -5mA), and deposition time (10s to 60s). The data is organized into three primary categories: (1) Dynamic Gas Sensing Records, featuring a 3-loop exposure sequence to varying acetone concentrations (0.1 ppm to 1.0 ppm); (2) Thermal Characterization Profiles, providing baseline resistance-temperature behavior for all 72 samples; and (3) Statistical Performance Metrics, including Signal-to-Noise Ratio (SNR) calculations and noise scaling analysis. This multi-parametric matrix (comprising over 2,000 sensing cycles) provides a critical foundation for machine learning-based gas identification and the optimization of nanomanufacturing protocols for highly sensitive, low-cost gas sensors.

Resistance Response and Heating Profiles of Electro-deposited ZnO Nanostructures for E-Nose Acetone Sensing

2026-04-10T00:00:00Z

Resistance Response and Heating Profiles of Electro-deposited ZnO Nanostructures for E-Nose Acetone Sensing Garay-Rairan, Fabian; Wang, Qi; Tricoli, Antonio; Qian, Jing; Lensky, Artem; Murugappan, Krishnan; Suominen, Hanna This dataset contains the experimental performance records of two high-performing zinc oxide (ZnO) nanostructured sensors developed for electronic nose (E-Nose) applications. The data includes resistance measurements over time during exposure to varying concentrations of acetone, as well as the thermal characterization (heating process) of the samples. The sensors were fabricated using electrodeposition with different molarities (0.1M and 0.2M ZnCl2) and current densities (250uA and 3mA). The records show how the system responds to changes, how it recovers, and how stable the signal-to-noise ratio (SNR) is. This information is important for machine learning-based gas identification and sensitivity optimization in nanomanufacturing.

In-Depth Conceptual Study of an Enhanced Plasmonic Sensing System Using Antireflective Coatings and Perovskites for the Detection of Infectious Viral Antigens

2022-01-01T00:00:00Z

In-Depth Conceptual Study of an Enhanced Plasmonic Sensing System Using Antireflective Coatings and Perovskites for the Detection of Infectious Viral Antigens Das, Chandreyee Manas; Guo, Yan; Poenar, Daniel Puiu; Ramaswamy, Yogambha; Xiong, Jiaqing; Yin, Ming-Jie; Yong, Ken-Tye Since its beginning, various countries have gone through multiple waves of surging COVID-19 infections. With the emergence of variants like Delta and Omicron, the disease is highly contagious and has the ability to spread at an alarming rate. In such scenarios, a quick and effective detection system is highly desirable. In this study, we present the concept of a surface plasmon resonance (SPR) based sensing system that can be utilized efficiently and reliably for the detection of SARS-CoV-2 antigens. The SPR system offers multiple advantages like real-time and label-free sensing of analytes and commercial systems have been in the market for more than two decades. Antireflective coatings (ARCs) have a number of application areas because of their unique properties. But they have seldom been used in the area of SPR sensing Hence, with the help of simulation, we make use of these coatings as intermediate layers and propose an enhanced sensing scheme by making use of ARCs of TiO2 and SiO2 and perovskite materials BaTiO3, PbTiO3, and SrTiO3. We found that, using TiO2, SiO2, and PbTiO3, a maximum sensitivity of 392 degRIU-1 can be obtained which is 5.29-fold enhancement as compared to the standard SPR arrangement using gold.

Platelet Mechanobiology Inspired Microdevices: From Hematological Function Tests to Disease and Drug Screening

2022-01-01T00:00:00Z

Platelet Mechanobiology Inspired Microdevices: From Hematological Function Tests to Disease and Drug Screening Zhang, Yingqi; Jiang, Fengtao; Chen, Yunfeng; Ju, Lining Arnold Platelet function tests are essential to profile platelet dysfunction and dysregulation in hemostasis and thrombosis. Clinically they provide critical guidance to the patient management and therapeutic evaluation. Recently, the biomechanical effects induced by hemodynamic and contractile forces on platelet functions attracted increasing attention. Unfortunately, the existing platelet function tests on the market do not sufficiently incorporate the topical platelet mechanobiology at play. Besides, they are often expensive and bulky systems that require large sample volumes and long processing time. To this end, numerous novel microfluidic technologies emerge to mimic vascular anatomies, incorporate hemodynamic parameters and recapitulate platelet mechanobiology. These miniaturized and cost-efficient microfluidic devices shed light on high-throughput, rapid and scalable platelet function testing, hematological disorder profiling and antiplatelet drug screening. Moreover, the existing antiplatelet drugs often have suboptimal efficacy while incurring several adverse bleeding side effects on certain individuals. Encouraged by a few microfluidic systems that are successfully commercialized and applied to clinical practices, the microfluidics that incorporate platelet mechanobiology hold great potential as handy, efficient, and inexpensive point-of-care tools for patient monitoring and therapeutic evaluation. Hereby, we first summarize the conventional and commercially available platelet function tests. Then we highlight the recent advances of platelet mechanobiology inspired microfluidic technologies. Last but not least, we discuss their future potential of microfluidics as point-of-care tools for platelet function test and antiplatelet drug screening.

Optical imaging spectroscopy for rapid, primary screening of SARS-CoV-2: a proof of concept

2022-01-01T00:00:00Z

Optical imaging spectroscopy for rapid, primary screening of SARS-CoV-2: a proof of concept Gomez-Gonzalez, Emilio; Barriga-Rivera, Alejandro; Fernandez-Muñoz, Beatriz; Navas-Garcia, Jose Manuel; Fernandez-Lizaranzu, Isabel; Munoz-Gonzalez, Francisco Javier; Parrilla-Giraldez, Ruben; Requena-Lancharro, Desiree; Gil-Gamboa, Pedro; Rosell-Valle, Cristina; Gomez-Gonzalez, Carmen; Mayorga-Buiza, Maria Jose; Martin-Lopez, Maria; Muñoz, Olga; Gomez-Martin, Juan Carlos; Relimpio-Lopez, Maria Isabel; Aceituno-Castro, Jesus; Perales-Esteve, Manuel A.; Puppo-Moreno, Antonio; Garcia-Cozar, Francisco Jose; Olvera-Collantes, Lucia; Gomez-Diaz, Raquel; de los Santos-Trigo, Silvia; Huguet-Carrasco, Monserrat; Rey, Manuel; Gomez, Emilia; Sanchez-Pernaute, Rosario; Padillo-Ruiz, Javier; Marquez-Rivas, Javier Effective testing is essential to control the coronavirus disease 2019 (COVID-19) transmission. Here we report a-proof-of-concept study on hyperspectral image analysis in the visible and near-infrared range for primary screening at the point-of-care of SARS-CoV-2. We apply spectral feature descriptors, partial least square-discriminant analysis, and artificial intelligence to extract information from optical diffuse reflectance measurements from 5 µL fluid samples at pixel, droplet, and patient levels. We discern preparations of engineered lentiviral particles pseudotyped with the spike protein of the SARS-CoV-2 from those with the G protein of the vesicular stomatitis virus in saline solution and artificial saliva. We report a quantitative analysis of 72 samples of nasopharyngeal exudate in a range of SARS-CoV-2 viral loads, and a descriptive study of another 32 fresh human saliva samples. Sensitivity for classification of exudates was 100% with peak specificity of 87.5% for discernment from PCR-negative but symptomatic cases. Proposed technology is reagent-free, fast, and scalable, and could substantially reduce the number of molecular tests currently required for COVID-19 mass screening strategies even in resource-limited settings.

Implantation and long-term assessment of the stability and biocompatibility of a novel 98 channel suprachoroidal visual prosthesis in sheep

2021-01-01T00:00:00Z

Implantation and long-term assessment of the stability and biocompatibility of a novel 98 channel suprachoroidal visual prosthesis in sheep Eggenberger, Samuel Christian; James, Natalie L.; Ho, Cherry; Eamegdool, Steven S.; Tatarinoff, Veronika; Craig, Naomi A.; Gow, Barry S.; Wan, Susan; Dodds, Christopher W. D.; La Hood, Donna; Gilmour, Aaron; Donahoe, Shannon L.; Krockenberger, Mark; Tumuluri, Krishna; da Cruz, Melville J.; Grigg, John R.; McCluskey, Peter; Lovell, Nigel H.; Madigan, Michele C.; Fung, Adrian T.; Suaning, Gregg J. Severe visual impairment can result from retinal degenerative diseases such as retinitis pigmentosa, which lead to photoreceptor cell death. These pathologies result in extensive neural and glial remodelling, with survival of excitable retinal neurons that can be electrically stimulated to elicit visual percepts and restore a form of useful vision. The Phoenix99 Bionic Eye is a fully implantable visual prosthesis, designed to stimulate the retina from the suprachoroidal space. In the current study, nine passive devices were implanted in an ovine model from two days to three months. The impact of the intervention and implant stability were assessed using indirect ophthalmoscopy, infrared imaging, and optical coherence tomography to establish the safety profile of the surgery and the device. The biocompatibility of the device was evaluated using histopathological analysis of the tissue surrounding the electrode array, with a focus on the health of the retinal cells required to convey signals to the brain. Appropriate stability of the electrode array was demonstrated, and histological analysis shows that the fibrotic and inflammatory response to the array was mild. Promising evidence of the safety and potential of the Phoenix99 Bionic Eye to restore a sense of vision to the severely visually impaired was obtained.

Molecular stabilization of sub-nanometer Cu clusters for selective CO2 electro-methanation

2021-01-01T00:00:00Z

Molecular stabilization of sub-nanometer Cu clusters for selective CO2 electro-methanation Li, Fengwang Electrochemical CO 2 methanation powered by renewable electricity provides a promising approach to utilizing CO 2 in the form of a high-energy-density, clean fuel. Cu nanoclusters have been predicted by theoretical calculations to improve methane selectivity. Direct electrochemical reduction of Cu-based metal-organic frameworks (MOFs) results in large-size Cu nanoparticles which favor multi-carbon products. Herein, we report an electrochemical oxidation-reduction method to prepare Cu clusters from MOFs. This derived Cu clusters exhibit a faradaic efficiency of 51.2% for CH 4 with a partial current density >150 mA cm -2 . High-resolution microscopy, in-situ X-ray absorption spectroscopy, in-situ Raman spectroscopy, and a collective of ex-situ spectroscopies indicate that the distinctive CH 4 selectivity is due to the sub-nanometer size of the derived materials as well as stabilization of the clusters by residual ligands of the pristine MOF. This work offers a new insight into steering product selectivity of Cu by an electrochemical processing method.

Hyperspectral image processing for the identification and quantification of lentiviral particles in fluid samples

2021-01-01T00:00:00Z

Hyperspectral image processing for the identification and quantification of lentiviral particles in fluid samples Gomez-Gonzalez, Emilio; Fernandez-Muñoz, Beatriz; Barriga-Rivera, Alejandro; Navas-Garcia, Jose Manuel; Fernandez-Lizaranzu, Isabel; Munoz-Gonzalez, Francisco Javier; Parrilla-Giraldez, Ruben; Requena-Lancharro, Desiree; Guerrero-Claro, Manuel; Gil-Gamboa, Pedro; Rosell-Valle, Cristina; Gomez-Gonzalez, Carmen; Mayorga-Buiza, Maria Jose; Martin-Lopez, Maria; Muñoz, Olga; Martin, Juan Carlos Gomez; Lopez, Maria Isabel Relimpio; Aceituno-Castro, Jesus; Perales-Esteve, Manuel A.; Puppo-Moreno, Antonio; Cozar, Francisco Jose Garcia; Olvera-Collantes, Lucia; de los Santos-Trigo, Silvia; Gomez, Emilia; Pernaute, Rosario Sanchez; Padillo-Ruiz, Javier; Marquez-Rivas, Javier Optical spectroscopic techniques have been commonly used to detect the presence of biofilm-forming pathogens (bacteria and fungi) in the agro-food industry. Recently, near-infrared (NIR) spectroscopy revealed that it is also possible to detect the presence of viruses in animal and vegetal tissues. Here we report a platform based on visible and NIR (VNIR) hyperspectral imaging for non-contact, reagent free detection and quantification of laboratory-engineered viral particles in fluid samples (liquid droplets and dry residue) using both partial least square-discriminant analysis and artificial feed-forward neural networks.

Clinical Implications of IL-32, IL-34 and IL-37 in Atherosclerosis: Speculative Role in Cardiovascular Manifestations of COVID-19

2021-01-01T00:00:00Z

Clinical Implications of IL-32, IL-34 and IL-37 in Atherosclerosis: Speculative Role in Cardiovascular Manifestations of COVID-19 Law, Ching Chee; Puranik, Rajesh; Fan, Jingchun; Fei, Jian; Hambly, Brett D.; Bao, Shisan Atherosclerosis, which is a primary cause of cardiovascular disease (CVD) deaths around the world, is a chronic inflammatory disease that is characterised by the accumulation of lipid plaques in the arterial wall, triggering inflammation that is regulated by cytokines/chemokines that mediate innate and adaptive immunity. This review focuses on IL-32, -34 and -37 in the stable vs. unstable plaques from atherosclerotic patients. Dysregulation of the novel cytokines IL-32, -34 and -37 has been discovered in atherosclerotic plaques. IL-32 and -34 are pro-atherogenic and associated with an unstable plaque phenotype; whereas IL-37 is anti-atherogenic and maintains plaque stability. It is speculated that these cytokines may contribute to the explanation for the increased occurrence of atherosclerotic plaque rupture seen in patients with COVID-19 infection. Understanding the roles of these cytokines in atherogenesis may provide future therapeutic perspectives, both in the management of unstable plaque and acute coronary syndrome, and may contribute to our understanding of the COVID-19 cytokine storm.

Feasibility of marker-free motion tracking for motion-corrected MRI and PET-MRI

2016-01-01T00:00:00Z

Feasibility of marker-free motion tracking for motion-corrected MRI and PET-MRI Kyme, Andre; Maclaren, Julian; Aksoy, Murat; Bammer, Roland Prospective motion correction is a very promising compensation approach for magnetic resonance imaging (MRI) studies impacted by motion. It has the advantage over retrospective methods of being applicable to any pulse sequence. In prospective motion correction of brain studies, the magnetic field gradients and radio frequency waveforms are adjusted in real time in response to motion of the head, thereby maintaining a fixed frame of reference for the brain inside the scanner. A key requirement of this approach is accurate and rapidly sampled head pose information. Optical motion tracking is typically used to obtain these pose estimates, however current methods are limited by the need to attach physical markers to the skin. This readily leads to decoupling of the head and marker motion, reducing the effectiveness of correction. In this work we investigate the feasibility and initial performance of an optical motion tracking method which does not require any attached markers. The method relies on detecting natural features or amplified features (from skins stamps on the forehead) using multiple cameras, and estimates pose using a 3D-2D registration between a growing database of known 3D locations on the forehead and these features. We have performed out-of-bore and in-bore experiments to test the accuracy performance of this marker-free method for very small feature patches consistent with the limited visibility afforded by head coils used during imaging. The results showed excellent agreement between the marker-free method and our current ground truth method based on wireless MR-sensitive markers.

Silhouette-based markerless motion estimation of awake rodents in PET

2017-01-01T00:00:00Z

Silhouette-based markerless motion estimation of awake rodents in PET Kyme, Andre; Strenge, Paul; Lee, Felicity; Meikle, Steven The ability to image the brain of a freely moving rodent using motion-compensated PET presents many exciting possibilities for exploring the links between brain function and behavior. Markerless optical approaches for pose estimation have several potential advantages over marker-based methods: improved accuracy and increased range of detectable motion; no `decoupling' of marker and head motion; and no acclimatization of the animals to attached markers. Our aim in this work was to describe and validate a silhouette-based multi-camera method for estimating the pose of a rat. Random-walk and K-means clustering approaches were very adaptable to uneven lighting and generally provided excellent object segmentations. In obtaining a high quality rat model, shape-from-silhouette and laser scanning both resulted in useful models; laser scanning provided sub-millimeter resolution with very few artifacts and was the method of choice. In our experimental validation, the 3D-2D (model-silhouette) optimization clearly converged to sub-degree and sub-millimeter alignment of the measured and estimated silhouettes. The average discrepancy between test points transformed using the estimated versus ground-truth poses was 0.94 mm ± 0.51 mm. This investigation focused on rigid motion of a rat phantom as a proof-of-principle of the technique. Future work will focus on investigating the potential of designing a non-rigid rodent body model in order to apply the method to a freely moving animal during PET imaging.

An optimized feature detector for markerless motion tracking in motion-compensated neuroimaging

2017-01-01T00:00:00Z

An optimized feature detector for markerless motion tracking in motion-compensated neuroimaging Henry, David; Yao, Yidi; Fulton, Roger R.; Kyme, Andre Head movements during PET and MRI scans can have a detrimental effect on image quality and quantitative measurements. For both modalities, motion correction methods exist that rely on accurate characterization of head motion. In the case of prospective correction in MRI, the motion estimates also need to be delivered in real-time. Motion tracking methods that rely on attached markers are susceptible to decoupling of the head and marker, hinder clinical workflow, and have line of sight issues due to the geometry of the bore and headcoil. In this study, we aim to optimize a methodology that measures head motion by detecting and tracking SIFT features native to the forehead. These features can be extracted and described in many ways, with different algorithms offering varying levels of computational efficiency and robustness to scene changes. A phantom study was performed to assess the accuracy and speed performance of five different feature detectors: SIFT, SURF, ORB, BRISK and AKAZE. Except for ORB, position estimates obtained using the different feature detectors showed similar agreement (error <;0.4 mm) with the ground-truth robot measurements. Processing time varied, with SURF, BRISK and AKAZE offering a substantial speed increase over SIFT while maintaining similar accuracy. We conclude that SURF, BRISK and AKAZE appear to be suitable alternative feature detectors to SIFT for prospective motion correction in MRI and MRI-PET.

Close-range feature-based head motion tracking for MRI and PET-MRI

2018-01-01T00:00:00Z

Close-range feature-based head motion tracking for MRI and PET-MRI Henry, David; Fulton, Roger R.; Maclaren, Julian; Aksoy, Murat; Bammer, Roland; Kyme, Andre Optical motion tracking systems are effective in measuring head motion during MRI and PET scans. However, most systems rely on tracking attached markers which can slip or move relative to the head. In this study, we aimed to validate a methodology which uses a stereo-optical camera system to track small feature patches on the forehead. This approach has the advantage that tracked features `native' to the skin can be tracked at very close range (<;5cm), making it ideal for use inside an MR scanner bore. 15 volunteers were instructed to perform 6 degree of freedom head motions while simultaneously being tracked by two systems - our feature-based tracking system, and a ground-truth multi-view optical system relying on passive IR-reflective markers attached to the back of the head. Sub-millimeter agreement between the two systems was achieved when head motion was purely rigid. In the case of non-rigid movement of the skin with respect to the head, large spikes in the motion traces derived from the feature-based algorithm were observed. This experiment provides a valuable dataset to benchmark future improvements and optimizations of the feature-based tracking algorithm, such as techniques to handle non-rigid motion.

Deep learning-based motion estimation for uninterrupted tracking of awake rodents in PET

2018-01-01T00:00:00Z

Deep learning-based motion estimation for uninterrupted tracking of awake rodents in PET Zhang, Shisheng; Balamurali, Mehala; Kyme, Andre The ability to image the brain of awake rodents using motion-compensated positron emission tomography (PET) presents many exciting possibilities for exploring the links between brain function and behavior. A key requirement of this approach is obtaining accurate estimates of animal pose throughout a scan. Our present motion tracking approach suffers crucial line-of-sight limitations which leads to tracking "dropout" and subsequent loss of motion information that can be used for motion correction. The proportion of a scan affected can range anywhere from 5% for sedentary subjects up to >50% for highly active subjects. The aim of this work was to investigate the feasibility of augmenting optical motion tracking with a video-based deep learning motion estimation method to mitigate the impact of tracking drop-out.A deep convolutional neural network (CNN) based regression approach for estimating six rigid-body motion parameters is proposed. We tested our model using multi-view camera images of a rat phantom under robotic control. The commanded robot motion provided the labels for our data. We compared the performance of deep learning-based motion estimation for simulated gaps in the motion sequence against the robot ground truth. We also compared deep learning to naïve linear interpolation of motion across the gaps. Deep learning provided promising alignment with the ground truth motion, in many cases sub-degree/sub-mm. The root mean square error for the deep learning and interpolation methods versus ground-truth was 1.26° and 23.64° (y-axis rotation) and 0.77 mm and 6.57 mm (z-position), respectively.Deep learning-based rigid-body motion estimation from multi-view video appears promising as a solution for augmenting optical tracking. Future work will focus on (i) the use of a Long Short-Term Memory (LSTM) unit to better model temporal information in the motion trace and (ii) incorporation of the known camera calibration to further constrain pose estimates.

Non-rigid motion detection for motion tracking of the head

2019-01-01T00:00:00Z

Non-rigid motion detection for motion tracking of the head Henry, David; Fulton, Roger R.; Maclaren, Julian; Aksoy, Murat; Bammer, Roland; Kyme, Andre Optical motion tracking systems are effective tools for measuring head motion during MRI and PET scans in order to correct for motion. Most systems rely on the attachment of fiducial markers which can slip or become decoupled from the head, causing erroneous motion estimates which can introduce further image artifacts. In this work, we investigated two methods of detecting non-rigid motion, both of which can be easily incorporated into a stereo-optical feature-based motion tracking system. The tracking system tracks detected features on small patches of the forehead. By monitoring these features, surface deformations on parts of the face that deform non-rigidly with respect to the rest of the head can be detected and potentially characterized. We investigated two methods of detecting non-rigid deformations: one involved measuring distances between detected landmarks and comparing these distances to previous frames; the other used a neural network to classify a group of landmarks as either `rigid' or `non-rigid'. A simulation tool was also developed to aid in the characterization of non-rigid motion and its effects. Landmark distance discrepancies were found to be correlated closely with pose measurement errors in the feature-based motion tracking system, suggesting it is a useful metric for detecting non-rigid motion. The trained neural network was able to classify a collection of landmarks as 'rigid' with 99.8 % accuracy and classified the `non-rigid' case with 93.3 % accuracy.

Characterization of the Intel RealSense D415 Stereo Depth Camera for Motion-Corrected CT Imaging

2019-01-01T00:00:00Z

Characterization of the Intel RealSense D415 Stereo Depth Camera for Motion-Corrected CT Imaging Dashtbani Moghari, Mahdieh; Noonan, Philip; Henry, David; Fulton, Roger R.; Young, Noel; Kyme, Andre A combination of non-contrast CT (NCCT) and CT Perfusion (CTP) imaging is the most common regime for evaluation of acute ischemic stroke patients. CTP-based image analysis is known to be compromised by patient head motion. However, there is currently no technique to compensate for intra-frame head motion during CTP acquisition. In this work, we investigated the feasibility of using the small form factor Intel RealSense D415 stereo depth camera to obtain accurate head pose estimates for intra-frame motion correction in CTP. First, we quantitatively evaluated head movement in a cohort of 72 acute stroke cases. Then we characterized the performance of the Intel D415 against ground-truth robotic motion and the clinically validated OptiTrack marker-based motion tracking system. The results showed that head motion during CTP imaging of acute stroke of patients is extremely common, with around 50% of patients moving > 5 mm and 1 deg and around 20% moving 10-100 mm and rotating 3-20 deg. The pose accuracy of the Intel for controlled robotic motion was approximately 5 mm and 2 deg. For translations and rotations, respectively. For human head motion using the OptiTrack as ground truth, the accuracy was approximately 4 mm (except for lateral motion) and 1.25 deg, respectively. Although poorer than what is needed clinically, there is a lot of potential to optimize performance and potentially achieve an accuracy consistently around 1 mm and 1 deg.

Markerless motion estimation for motion-compensated clinical brain imaging

2018-01-01T00:00:00Z

Markerless motion estimation for motion-compensated clinical brain imaging Kyme, Andre; Se, Stephen; Meikle, Steven R.; Fulton, Roger R. Motion-compensated brain imaging can dramatically reduce the artifacts and quantitative degradation associated with voluntary and involuntary subject head motion during positron emission tomography (PET), single photon emission computed tomography (SPECT) and computed tomography (CT). However, motion-compensated imaging protocols are not in widespread clinical use for these modalities. A key reason for this seems to be the lack of a practical motion tracking technology that allows for smooth and reliable integration of motion-compensated imaging protocols in the clinical setting. We seek to address this problem by investigating the feasibility of a highly versatile optical motion tracking method for PET, SPECT and CT geometries. The method requires no attached markers, relying exclusively on the detection and matching of distinctive facial features. We studied the accuracy of this method in 16 volunteers in a mock imaging scenario by comparing the estimated motion with an accurate marker-based method used in applications such as image guided surgery. A range of techniques to optimize performance of the method were also studied. Our results show that the markerless motion tracking method is highly accurate (<2 mm discrepancy against a benchmarking system) on an ethnically diverse range of subjects and, moreover, exhibits lower jitter and estimation of motion over a greater range than some marker-based methods. Our optimization tests indicate that the basic pose estimation algorithm is very robust but generally benefits from rudimentary background masking. Further marginal gains in accuracy can be achieved by accounting for non-rigid motion of features. Efficiency gains can be achieved by capping the number of features used for pose estimation provided that these features adequately sample the range of head motion encountered in the study. These proof-of-principle data suggest that markerless motion tracking is amenable to motion-compensated brain imaging and holds good promise for a practical implementation in clinical PET, SPECT and CT systems.

Open-field PET: Simultaneous brain functional imaging and behavioural response measurements in freely moving small animals

2019-01-01T00:00:00Z

Open-field PET: Simultaneous brain functional imaging and behavioural response measurements in freely moving small animals Kyme, Andre; Angelis, Georgios I.; Eisenhuth, John; Fulton, Roger R.; Zhou, Victor; Hart, Genevra; Popovic, Kata; Akhtar, Mahmood; Ryder, William J.; Clemens, Kelly J.; Balleine, Bernard W.; Parmar, Arvind; Pascali, Giancarlo; Perkins, Gary; Meikle, Steven R. A comprehensive understanding of how the brain responds to a changing environment requires techniques capable of recording functional outputs at the whole-brain level in response to external stimuli. Positron emission tomography (PET) is an exquisitely sensitive technique for imaging brain function but the need for anaesthesia to avoid motion artefacts precludes concurrent behavioural response studies. Here, we report a technique that combines motion-compensated PET with a robotically-controlled animal enclosure to enable simultaneous brain imaging and behavioural recordings in unrestrained small animals. The technique was used to measure in vivo displacement of [11C]raclopride from dopamine D2 receptors (D2R) concurrently with changes in the behaviour of awake, freely moving rats following administration of unlabelled raclopride or amphetamine. The timing and magnitude of [11C]raclopride displacement from D2R were reliably estimated and, in the case of amphetamine, these changes coincided with a marked increase in stereotyped behaviours and hyper-locomotion. The technique, therefore, allows simultaneous measurement of changes in brain function and behavioural responses to external stimuli in conscious unrestrained animals, giving rise to important applications in behavioural neuroscience.

Marker-free optical stereo motion tracking for in-bore MRI and PET-MRI application

2020-01-01T00:00:00Z

Marker-free optical stereo motion tracking for in-bore MRI and PET-MRI application Kyme, Andre; Aksoy, Murat; Henry, David; Bammer, Roland; Maclaren, Julian Purpose: Prospective motion correction is arguably the “silver bullet” solution for magnetic resonance imaging (MRI) studies impacted by motion, applicable to almost any pulse sequence and immune from the spin history artifacts introduced by a moving object. In prospective motion correction, the magnetic field gradients and radio frequency waveforms are adjusted in real time in response to measured head motion so as to maintain the head in a stationary reference frame relative to the scanner. Vital for this approach are accurate and rapidly sampled head pose measurements, which may be obtained optically using cameras. However, most optical methods are limited by the need to attach physical markers to the skin, which leads to decoupling of head and marker motion and reduces the effectiveness of correction. In this work we investigate the feasibility and initial performance of a stereo-optical motion tracking method which does not require any attached markers. Methods: The method relies on detecting distinctive natural features or amplified features (using skin stamps) directly on the forehead in multiple camera views, and then deriving pose estimates via a 3D-2D registration between the skin features and a database of forehead landmarks. To demonstrate the feasibility and potential accuracy of the marker-free method for discrete (step-wise) head motion, we performed out-of-bore and in-bore experiments using robotically and manually controlled phantoms in addition to in-bore testing on human volunteers. We also developed a convenient out-of-bore test bed to benchmark and optimize the motion tracking performance. Results: For out-of-bore phantom tests, the pose estimation accuracy (compared to robotic ground truth) was 0.14 mm and 0.23 degrees for incremental translation and rotation, respectively. For arbitrary motion, the pose accuracy obtained using the smallest forehead feature patch was equivalent to 0.21 0.11 mm positional accuracy in the striatum. For in-bore phantom experiments, the accuracy of rigid-body motion parameters (compared to wireless MR-sensitive markers) was 0.08–0.41 0.18 mm/0.05–0.3 0.12 deg and 0.14–0.16 0.12 mm/0.08-0.17 0.08 deg for the small and large feature patches, respectively. In vivo results in human volunteers indicated sub-millimeter and sub-degree pose accuracy for all rotations and translations except the depth direction (max error 1.8 mm) when compared to a registration-based approach. Conclusions: In both bench-top and in vivo experiments we demonstrate the feasibility of using very small feature patches directly on the skin to obtain high accuracy head pose measurements needed for motion-correction in MRI brain studies. The optical technique uses in-bore cameras and is consistent with the limited visibility of the forehead afforded by head coils used in brain imaging. Future work will focus on optimization of the technique and demonstration in prospective motion correction.