Tomography Imaging Techniques Research Articles

Using artifact suppression OCT based on polarization multiplexing for tomographic imaging of LCD screens

Defect detection in the inner layers of liquid crystal display (LCD) panels is crucial for the quality control of displays. Optical coherence tomography (OCT), a nondestructive, high-resolution tomographic imaging technique, has been applied in the inspection of display panels. However, the artifacts that arise in imaging multilayer samples remain a challenge. In this study, we propose and validate a method for artifact removal in coherent imaging of multilayer refractive samples. These samples exhibit complex autocorrelation artifacts due to self-interference and multiple reflections. Two orthogonally polarized reference beams with fixed phase shifts, combined with the proposed algorithm, are employed to suppress the autocorrelation in the sample light path. To address the issue of mirror artifacts caused by real spectrum signals, the intensity ratio of the two orthogonally polarized reference beams is adjusted, allowing distinction between real signals and mirror artifacts, thus achieving full-range imaging. Experiments were conducted to measure 3D images of multilayer quartz glass sheets, inclined ceramic blocks, and LCD panels, validating the reliability of the proposed approach and demonstrating its advantages in display defect detection.

ANMCO/GISE/SICOA Consensus document: Role of coronary computed tomography angiography in chronic coronary syndromes

Chronic coronary syndromes (CCS) are the most common clinical manifestation of coronary atherosclerosis. Coronary computed tomography angiography (CCTA) is a recent innovation in non-invasive cardiac imaging. It is the only anatomical imaging method that allows direct visualization of the coronary lumen, vessel walls, and atherosclerotic plaques, offering high sensitivity and a strong negative predictive value. CCTA is particularly useful in identifying or ruling out coronary atherosclerosis in the context of CCS and serves as an excellent filter for invasive coronary angiography. Compared to other non-invasive functional imaging tests (stress echocardiography, single photon emission computed tomography, magnetic resonance imaging, positron emission tomography), CCTA provides detailed characterization of both obstructive and non-obstructive plaques, enabling accurate risk stratification and guiding therapy. Recent advances in computed tomography technology and imaging techniques further extend the use of CCTA beyond plaque and stenosis evaluation, offering also functional lesion information. This consensus document aims to detail the technical aspects of CCTA and illustrate its role in optimizing CCS diagnostic and therapeutic management, enhancing precision medicine and personalized patient care.

Effect of tracer size distribution on magnetic particle imaging performance

Abstract Magnetic particle imaging (MPI) is a tracer-based tomographic imaging technique utilized in applications such as lung perfusion imaging, cancer diagnosis, stem cell tracking, etc. The goal of translating MPI to clinical use has prompted studies on further improving the spatial-temporal resolutions of MPI through various methods, including image reconstruction algorithm, scanning trajectory design, magnetic field profile design, and tracer design. Iron oxide magnetic nanoparticles (MNPs) are favored for MPI and magnetic resonance imaging (MRI) over other materials due to their high biocompatibility, low cost, and ease of preparation and surface modification. For core–shell MNPs, the tracers’ magnetic core size and non-magnetic coating layer characteristics can significantly affect MPI signals through dynamic magnetization relaxations. Most works to date have assumed an ensemble of MNP tracers with identical sizes, ignoring that artificially synthesized MNPs typically follow a log-normal size distribution, which can deviate theoretical results from experimental data. In this work, we first characterize the size distributions of four commercially available iron oxide MNP products and then model the collective magnetic responses of these MNPs for MPI applications. For an ensemble of MNP tracers with size standard deviations of σ, we applied a stochastic Langevin model to study the effect of size distribution on MPI imaging performance. Under an alternating magnetic field (AMF), i.e., the excitation field in MPI, we collected the time domain dynamic magnetizations (M-t curves), magnetization-field hysteresis loops (M-H curves), point-spread functions (PSFs), and higher harmonics from these MNP tracers. The intrinsic MPI spatial resolution, which is related to the full width at half maximum (FWHM) of the PSF profile, along with the higher harmonics, serve as metrics to provide insights into how the size distribution of MNP tracers affects MPI performance.

Dual-domain Wasserstein Generative Adversarial Network with Hybrid Loss for Low-dose CT Imaging

Objective.Low-dose computed tomography (LDCT) has gained significant attention in hospitals and clinics as a popular imaging modality for reducing the risk of x-ray radiation. However, reconstructed LDCT images often suffer from undesired noise and artifacts, which can negatively impact diagnostic accuracy. This study aims to develop a novel approach to improve LDCT imaging performance.Approach.A dual-domain Wasserstein generative adversarial network (DWGAN) with hybrid loss is proposed as an effective and integrated deep neural network (DNN) for LDCT imaging. The DWGAN comprises two key components: a generator (G) network and a discriminator (D) network. TheGnetwork is a dual-domain DNN designed to predict high-quality images by integrating three essential components: the projection-domain denoising module, filtered back-projection-based reconstruction layer, and image-domain enhancement module. TheDnetwork is a shallow convolutional neural network used to differentiate between real (label) and generated images. To prevent the reconstructed images from becoming excessively smooth and to preserve both structural and textural details, a hybrid loss function with weighting coefficients is incorporated into the DWGAN.Main results.Numerical experiments demonstrate that the proposed DWGAN can effectively suppress noise and better preserve image details compared with existing methods. Moreover, its application to head CT data confirms the superior performance of the DWGAN in restoring structural and textural details.Significance.The proposed DWGAN framework exhibits excellent performance in recovering structural and textural details in LDCT images. Furthermore, the framework can be applied to other tomographic imaging techniques that suffer from image distortion problems.

New Frontiers in Asthma Chest Imaging.

Modern pulmonary imaging can reveal underlying pathological and pathophysiological changes in the lungs of people with asthma, with important clinical implications. A multitude of imaging modalities are now used to examine underlying structure/function relationships including computed tomography, magnetic resonance imaging, optical coherence tomography, and endobronchial ultrasound. Imaging-based biomarkers from these techniques, including airway dimensions, blood vessel volumes, mucus scores, ventilation defect extent and air trapping extent, often have increased sensitivity compared to traditional lung function measurements, and are increasingly used as endpoints in clinical trials. Imaging has been crucial to recent improvements in our understanding of relationships between T2-inflammation, eosinophilia, and mucus extent. With the advent of effective anti-T2 biologic therapies, computed tomography and magnetic resonance imaging techniques can identify not just which patients benefit from therapy, but why they benefit. Clinical trials have begun to assess the utility of imaging to prospectively plan airway therapy targets in bronchial thermoplasty and have potential to direct future bronchoscopic therapies. Together, imaging techniques provide a diverse set of tools to investigate how spatially-distributed airway, blood, and parenchymal abnormalities shape disease heterogeneity in patients with asthma.

Neural-field-based image reconstruction for bioluminescence tomography

Deep learning (DL)-based image reconstruction methods have garnered increasing interest in the last few years. Numerous studies demonstrate that DL-based reconstruction methods function admirably in optical tomographic imaging techniques, such as bioluminescence tomography (BLT). Nevertheless, nearly every existing DL-based method utilizes an explicit neural representation for the reconstruction problem, which either consumes much memory space or requires various complicated computations. In this paper, we present a neural field (NF)-based image reconstruction scheme for BLT that uses an implicit neural representation. The proposed NF-based method establishes a transformation between the coordinate of an arbitrary spatial point and the source value of the point with a relatively light-weight multilayer perceptron, which has remarkable computational efficiency. Another simple neural network composed of two fully connected layers and a 1D convolutional layer is used to generate the neural features. Results of simulations and experiments show that the proposed NF-based method has similar performance to the photon density complement network and the two-stage network, while consuming fewer floating point operations with fewer model parameters.

Cadaveric validation of markerless tracking using weightbearing computed tomography versus conventional computed tomography imaging techniques

This study aimed to validate the use of weightbearing computed tomography against conventional computed tomography and against bead tracking for markerless tracking of key foot and ankle bones. A left cadaveric limb was implanted with tantalum beads and underwent conventional computed tomography and weightbearing computed tomography scanning, followed by biplane fluoroscopy motion capture to simulate gait. Bone models from conventional computed tomography and weightbearing computed tomography were compared for surface differences and kinematic analysis across six joints. Results showed the average surface distance difference across all weightbearing computed tomography bones were a fraction of a voxel smaller than the conventional computed tomography bones on average. Additionally, the absolute mean and standard deviation of the mean angle differences across all trials, joints, and planes was less than one degree. Weightbearing computed tomography demonstrated comparable accuracy to conventional computed tomography and to bead tracking, confirming its utility in dynamic biomechanical analysis with reduced radiation exposure and the ability to image under load. This validation supports weightbearing computed tomography's broader adoption in clinical and research settings for enhanced foot and ankle diagnostics and treatment.

Comparative Analysis of Ocular Morphology in Dromedary Camels: Insights from Ultrasound and Computed Tomography Imaging Techniques

Comparative Analysis of Ocular Morphology in Dromedary Camels: Insights from Ultrasound and Computed Tomography Imaging Techniques

Optical Coherence Tomography Image Analysis for Detection of Alzheimer’s Disease: A Comprehensive Structured Review

Optical Coherence Tomography (OCT) has emerged as a promising non-invasive imaging modality for the early detection of Alzheimer’s Disease (AD). This systematic literature review aims to consolidate current research on OCT image analysis for AD detection, addressing the growing need for early and accurate diagnostic tools. Despite the advances in neuroimaging, early diagnosis of AD remains challenging due to its asymptomatic nature in initial stages and the invasiveness of traditional methods. To achieve this, we conducted an extensive search of related articles from reputable databases (Scopus and Web of Science), focusing on studies published between 2022-2024. The flow of study was based on PRISMA framework. The database found (n = 29) final primary data. This review was divided into three themes, (1) retinal and ocular biomarkers for AD, (2) optical coherence tomography angiography (OCTA) and imaging techniques, and (3) machine learning and computational approaches for Alzheimer’s disease diagnosis. Key findings include the enlargement of the periarteriole capillary-free zone and changes in retinal nerve fibre layer thickness as potential AD biomarkers. Based on the review, the implementation of image analysis for OCT images have shown substantial potential for AD detection. By evaluating the past studies, gaps for the current research were discovered including the need for larger, more diverse cohorts and longitudinal studies to validate these biomarkers. In summary, detection of AD is possible through thorough OCT image analysis, but further research could be suggested to enhance its clinical applicability and reliability.

Radiosynthesis, Quality Control, and Small Animal Positron Emission Tomography Imaging of 68Ga-labelled Nano Molecules.

Small animal Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT) imaging techniques are crucial in preclinical cancer research, necessitating meticulous attention to radiotracer synthesis, quality assurance, and in vivo injection protocols. This study presents a comprehensive workflow tailored to enhance the robustness and reproducibility of small animal PET experiments. The synthesis process in the radiochemistry laboratory using 68Ga is detailed, highlighting stringent quality control and assurance protocols for each radiotracer production. Parameters such as concentration, molar activity, pH, and purity are rigorously monitored, aligning with standards applicable to human studies. This methodology introduces streamlined syringe preparation and a custom-designed 30G cannula for precise intravenous injections into mice. Monitoring of animal health during scanning, including temperature and heart rate, ensures their well-being throughout the procedure. Dosages for PET and SPECT scans are predetermined to balance data acquisition with minimizing radiation exposure to animals and researchers. Similarly, CT scans employ pre-programmed settings to limit radiation exposure, especially pertinent in long-term studies assessing treatment effects. By optimizing these steps, the workflow aims to standardize procedures, reduce variability, and enhance the quality of small animal PET/SPECT/CT imaging. This resource provides valuable insights for researchers seeking to improve the accuracy and reliability of preclinical investigations in molecular imaging, ultimately advancing the field.

Recent Advancement of Indocyanine Green Based Nanotheranostics for Imaging and Therapy of Coronary Atherosclerosis.

Atherosclerosis is a vascular intima condition in which any part of the circulatory system is affected, including the aorta and coronary arteries. Indocyanine green (ICG), a theranostic compound approved by the FDA, has shown promise in the treatment of coronary atherosclerosis after incorporation into nanoplatforms. By integration of ICG with targeting agents such as peptides or antibodies, it is feasible to increase its concentration in damaged arteries, hence increasing atherosclerosis detection. Nanotheranostics offers cutting-edge techniques for the clinical diagnosis and therapy of atherosclerotic plaques. Combining the optical properties of ICG with those of nanocarriers enables the improved imaging of atherosclerotic plaques and targeted therapeutic interventions. Several ICG-based nanotheranostics platforms have been developed such as polymeric nanoparticles, iron oxide nanoparticles, biomimetic systems, liposomes, peptide-based systems, etc. Theranostics for atherosclerosis diagnosis use magnetic resonance imaging (MRI), computed tomography (CT), near-infrared fluorescence (NIRF) imaging, photoacoustic/ultrasound imaging, positron emission tomography (PET), and single photon emission computed tomography (SPECT) imaging techniques. In addition to imaging, there is growing interest in employing ICG to treat atherosclerosis. In this review, we provide a conceptual explanation of ICG-based nanotheranostics for the imaging and therapy of coronary atherosclerosis. Moreover, advancements in imaging modalities such as MRI, CT, PET, SPECT, and ultrasound/photoacoustic have been discussed. Furthermore, we highlight the applications of ICG for coronary atherosclerosis.

Optimizing pulmonary carcinoma detection through image segmentation using evolutionary algorithms

<span lang="EN-US">This paper’s goal is to suggest an image segmentation technique for use with medical images, specifically computer tomography scan images, to aid doctors in understanding the images. To address a variety of picture segmentation issues, it is necessary to investigate and apply novel evolutionary algorithms. The study focuses on pulmonary carcinoma, which is the cancer that affects males the most frequently across the globe. For proper treatment and life-saving measures, early identification of lung cancer is essential. To identify lung cancer, doctors frequently employ the computed tomography imaging technique. In order to extract tumours from lung scans, the study analyses the effectiveness of three optimization algorithms: k-means clustering, particle swarm optimization, and modified guaranteed convergence particle swarm optimization. The study also examines the pre-processing performance of four filters, namely the mean, bilateral, gaussian, and laplacian filters, shows that the bilateral filter is best suited for CT scans of the body. To test the proposed technique on 30 examples of lung scans. The proposed algorithm is tested on 30 sample lung images. The results show that the modified guaranteed convergence particle swarm optimization algorithm has the highest accuracy of 96.01%.</span>

Comparison of the Effectiveness of Computed Tomography and Magnetic Resonance Imaging Techniques in Patient Groups Aged under and over 65 Years and Diagnosed with Ischemic Stroke in the Emergency Department

Objectives: Stroke is a condition with high morbidity and mortality. This study aims to investigate whether the effectiveness of Computed Tomography (CT) and diffusion-weighted Magnetic Resonance Imaging (MRI), the techniques that have a significant place in the diagnosis of ischemic stroke, the most common form of stroke, are affected by the physiological changes of advanced age. Methods: A total of 436 patients were included in the study. The study population was divided into two groups depending on age: those above 65 and those under 65. Medical files, both the emergency department and clinical ward files, of the patients who were admitted to the emergency department in nine months and admitted to the neurology clinic with the diagnosis of ischemic stroke were retrospectively analyzed. The time from admission to imaging was determined depending on patient files and the Hospital Management Information System (HBYS). The CT and MRI reports interpreted by radiologists were also reviewed. While recording the data, the presence of a lesion, its direction, and localization were also noted. Results: CT positivity was 21.3%, and the positivity of diffusion-weighted imaging was 82.1% in the study population. The time was shorter in the group of patients with positive CT results than in the group with negative CT results. In subjects under 65, the time between onset and imaging was shorter in the group with positive CT results than in the group with negative CT results. In subjects over 65, the time with positive CT results was not different from the group with negative CT results. It was determined that the mean time was shorter in the group with positive MRI results than in the group with negative results. In both the groups under the age of 65 and over the age of 65, the time interval was shorter in the patients with positive MRI results compared to those with negative MRI results. Conclusions: Regardless of the positivity or negativity of CT and MRI results, the mean time from symptom onset to imaging was shorter in the group under 65 years of age compared to the group over 65 years. Aging prolongs the time to admission and the neuroradiological response of geriatric patients.

Contemporary multimodality non-invasive cardiac imaging protocols for tetralogy of Fallot.

Tetralogy of Fallot is the most prevalent cyanotic congenital heart disease, requiring lifelong multimodality non-invasive cardiac imaging, such as echocardiography, cardiothoracic computed tomography, and cardiac magnetic resonance imaging. As imaging techniques continuously evolve and are gradually integrated into clinical practice, there is a critical need to update multimodality imaging protocols. Over the last two decades, cardiothoracic computed tomography imaging techniques have advanced remarkably, significantly enhancing its role in evaluating patients with tetralogy of Fallot. In this review, we describe contemporary multimodality non-invasive cardiac imaging protocols for tetralogy of Fallot, emphasizing the expanding role of cardiothoracic computed tomography. Additionally, we present standardized reporting forms designed to facilitate the clinical adoption of these protocols.

Comparison of choroidal thickness in healthy pregnant and preeclamptic women in a tertiary eye care center in Central India: A cross-sectional study

Aim: To compare the Subfoveal Choroidal Thickness (SFCT) measured by Enhanced Depth Imaging (EDI) technique of Spectral Domain Optical Coherence Tomography (SD-OCT) in healthy pregnant and preeclamptic women. Methods: Our study was cross-sectional hospital-based study in which healthy pregnant women and women having preeclampsia were selected from Obstetrics and Gynecology department and enrolled in it. The guidelines of the American College of Obstetricians and Gynecologists were used to diagnose the cases of preeclampsia. The study included 100 women (200 eyes) which were grouped into 50 healthy pregnant women (group 1), i.e., n = 100 eyes and 50 preeclamptic women (group 2), i.e., n = 100 eyes. SFCT was measured using the EDI technique of SD-OCT and data were entered in a Microsoft Excel sheet. Statistical analysis was done using Epi Info. Software version 7.2.1.0 (Atlanta, Georgia, US) and the results of both the groups were compared. Results: The mean SFCT in both the eyes of the healthy pregnant group and the preeclamptic group was 318.12 ± 37.12 µm and 209.04 ± 26.73 µm, respectively, with a P-value 0.001 showing a statistically significant difference between both the groups. Conclusion: The SFCT is significantly decreased in preeclamptic pregnant women than in healthy pregnant women.

Hybrid Molecular and Functional Micro-CT Imaging Reveals Increased Myocardial Apoptosis Preceding Cardiac Failure in Progeroid Ercc1 Mice

PurposeIn this study, we explored the role of apoptosis as a potential biomarker for cardiac failure using functional micro-CT and fluorescence molecular tomography (FMT) imaging techniques in Ercc1 mutant mice. Ercc1 is involved in multiple DNA repair pathways, and its mutations contribute to accelerated aging phenotypes in both humans and mice, due to the accumulation of DNA lesions that impair vital DNA functions. We previously found that systemic mutations and cardiomyocyte-restricted deletion of Ercc1 in mice results in left ventricular (LV) dysfunction at older age.Procedures and ResultsHere we report that combined functional micro-CT and FMT imaging allowed us to detect apoptosis in systemic Ercc1 mutant mice prior to the development of overt LV dysfunction, suggesting its potential as an early indicator and contributing factor of cardiac impairment. The detection of apoptosis in vivo was feasible as early as 12 weeks of age, even when global LV function appeared normal, underscoring the potential of apoptosis as an early predictor of LV dysfunction, which subsequently manifested at 24 weeks.ConclusionsThis study highlights the utility of combined functional micro-CT and FMT imaging in assessing cardiac function and detecting apoptosis, providing valuable insights into the potential of apoptosis as an early biomarker for cardiac failure.

Skin characterization of diabetes mellitus revealed by polarization-sensitive optical coherence tomography imaging.

Diabetes can lead to the glycation of proteins and dysfunction of skin collagen. Skin lesions are a prevalent clinical symptom of diabetes mellitus (DM). Early diagnosis and assessing the efficacy of treatment for DM are crucial for patient health management. However, performing a non-invasive skin assessment in the early stages of DM is challenging. By using the polarization-sensitive optical coherent tomography (PS-OCT) imaging technique, it is possible to noninvasively assess the skin changes caused by diabetes. The PS-OCT was used to monitor the polarization characteristics of mouse skin at different stages of diabetes. Based on a multi-layered adhesive tape model, we found that the polarization characteristics (retardation, optic axis, and polarization uniformity) were sensitive to the microstructure changes in the samples. Through this method, we observed significant changes in the polarization states of the skin as diabetes progressed. This was in line with the detected microstructure changes in skin collagen fibers using scanning electron microscopy. This study presents a highly useful approach for non-invasive skin assessment of diabetes.

Challenges, limitations, and pitfalls of PET and advanced MRI in patients with brain tumors: A report of the PET/RANO group.

Brain tumor diagnostics have significantly evolved with the use of positron emission tomography (PET) and advanced magnetic resonance imaging (MRI) techniques. In addition to anatomical MRI, these modalities may provide valuable information for several clinical applications such as differential diagnosis, delineation of tumor extent, prognostication, differentiation between tumor relapse and treatment-related changes, and the evaluation of response to anticancer therapy. In particular, joint recommendations of the Response Assessment in Neuro-Oncology (RANO) Group, the European Association of Neuro-oncology, and major European and American Nuclear Medicine societies highlighted that the additional clinical value of radiolabeled amino acids compared to anatomical MRI alone is outstanding and that its widespread clinical use should be supported. For advanced MRI and its steadily increasing use in clinical practice, the Standardization Subcommittee of the Jumpstarting Brain Tumor Drug Development Coalition provided more recently an updated acquisition protocol for the widely used dynamic susceptibility contrast perfusion MRI. Besides amino acid PET and perfusion MRI, other PET tracers and advanced MRI techniques (e.g. MR spectroscopy) are of considerable clinical interest and are increasingly integrated into everyday clinical practice. Nevertheless, these modalities have shortcomings which should be considered in clinical routine. This comprehensive review provides an overview of potential challenges, limitations, and pitfalls associated with PET imaging and advanced MRI techniques in patients with gliomas or brain metastases. Despite these issues, PET imaging and advanced MRI techniques continue to play an indispensable role in brain tumor management. Acknowledging and mitigating these challenges through interdisciplinary collaboration, standardized protocols, and continuous innovation will further enhance the utility of these modalities in guiding optimal patient care.

Anatomical studies on the PES region of Zebu cattle (Bos Taurus indicus) with special references to 3D computed tomography imaging technique

The 3D render volume reconstruction CT (3D-RVCT) produced detailed images of the PES region, determining its relationships with the surrounding structures. Despite extensive research in veterinary studies on the PES through gross anatomy and CT, there is a lack of studies on the PES of zebu cattle. The study aimed to analyze the PES of Zebu cattle using gross cross-sectional, radiographic, CT, and morphometric methods, with the use of 3D-RVCT to provide anatomical guidance for surgeons and students. The study was performed on sixteen PES regions to provide hard and soft tissues in CT images. Three are five tarsal bones and two large fused (III and IV) metatarsal bones that were completely fused except for their distal extremities, which were divided distally by the intertrochlear notch. The cortical thickness of the metatarsal bone was equal on both sides. The bony septum divided the medullary cavity between the two fused large metatarsal bones in the proximal distal half only and disappeared in the middle part. The reconstruction showed similar sizes in the right and left limbs, confirming the pes bones. The radiographic and CT images could be used as a normal reference for the interpretation of some clinical diseases in the PES. The 3D CT reconstruction of the pes bones was described by various CT oblique dorsal and plantar views. The study focuses on diagnosing PES disorders using CT imaging, improving medical interventions, improving Zebu cattle health outcomes, and empowering students to contribute to veterinary medicine research and advancements.

Towards limited-domain full waveform ambient noise inversion

SUMMARY Ambient noise tomography is a well-established tomographic imaging technique but the effect that spatially variable noise sources have on the measurements remains challenging to account for. Full waveform ambient noise inversion has emerged recently as a promising solution but is computationally challenging since even distant noise sources can have an influence on the interstation correlation functions and therefore requires a prohibitively large numerical domain, beyond that of the tomographic region of interest. We investigate a new strategy that allows us to reduce the simulation domain while still being able to account for distant contributions. To allow nearby numerical sources to account for distant true sources, we introduce correlated sources and generate a time-dependent effective source distribution at the boundary of a small region of interest that excites the correlation wavefield of a larger domain. In a series of 2-D numerical simulations, we demonstrate that the proposed methodology with correlated sources is able to successfully represent a far-field source that is simultaneously present with nearby sources and the methodology also successfully results in a robustly estimated noise source distribution. Furthermore, we show how beamforming results can be used as prior information regarding the azimuthal variation of the ambient noise sources in helping determine the far-field noise distribution. These experiments provide insight into how to reduce the computational cost needed to perform full waveform ambient noise inversion, which is key to turning it into a viable tomographic technique. In addition, the presented experiments may help reduce source-induced bias in time-dependent monitoring applications.