Static Images Research Articles

Imaging simulation analysis of space targets by different observed orbits

Abstract For most optical simulations of space targets, static imaging characteristics are studied with a pre-set angle and attitude which are less consistent with the actual situation for satellite detectors’ dynamic image. Especially when the detector and the target are in different orbits, the imaging angles and attitudes also vary. In this article, two kinds of observed orbits are selected to simulate the detector image results, and the observed attitude and angle are updated over time through the simulation process. Furthermore, a temperature field of the space target is also calculated as preconditioned data to be taken into account in the optical simulation, instead of roughly estimating the temperature. The result of the study reveals that when the satellite detector and target operate at coplanar orbits, closer distances (ranging from 236 km to 28 km) allow for the acquisition of more specific details regarding the target’s characteristics. This research may offer a new approach to selecting orbits to obtain high-quality imaging data.

Event-horizon-scale Imaging of M87* under Different Assumptions via Deep Generative Image Priors

Reconstructing images from the Event Horizon Telescope (EHT) observations of M87*, the supermassive black hole at the center of the galaxy M87, depends on a prior to impose desired image statistics. However, given the impossibility of directly observing black holes, there is no clear choice for a prior. We present a framework for flexibly designing a range of priors, each bringing different biases to the image reconstruction. These priors can be weak (e.g., impose only basic natural-image statistics) or strong (e.g., impose assumptions of black hole structure). Our framework uses Bayesian inference with score-based priors, which are data-driven priors arising from a deep generative model that can learn complicated image distributions. Using our Bayesian imaging approach with sophisticated data-driven priors, we can assess how visual features and uncertainty of reconstructed images change depending on the prior. In addition to simulated data, we image the real EHT M87* data and discuss how recovered features are influenced by the choice of prior.

Influence of Age, Gender and BMI on Normal Abdominal Aorta Diameter taken on Abdominal Sonography in Healthy Asymptomatic Pakistani Population

Objective: To evaluate the abdominal aorta diameter in asymptomatic Pakistani population to determine the associations between age, gender and BMI and abdominal aortic diameter measured by ultrasonography. Study Design: Case series. Place and Duration of Study: Department of Radiology, Combined Military Hospital, Lahore, Pakistan, from Jun to Dec 2021. Methodology: A total of ninety-four healthy asymptomatic subjects of both genders, between 18-80 years of age, were enrolled for the study. Aortic diameters were measured (inner to inner method) using electronic calipers on static images. The Anteroposterior and Transverse (TR) diameters were measured at three levels: the first at the aortic hiatus, which was directly below the abdominal aortic commencement, the second at the suprarenal (mid-point), and the third at the aortic bifurcation (lower level). Results: Males had significantly larger (p-value<0.001) anteroposterior and transverse abdominal aorta diameters than females, with abdominal aorta diameter values found to be significantly higher (p-value 0.001) in age group of greater than 40 years except anteroposterior distal abdominal aorta diameter. Similarly, a significant difference (p-value <0.001) was noted in abdominal aorta diameter among patients with different BMI groups other than distal abdominal aorta diameter. Conclusion: Abdominal aorta diameters vary greatly depending on age, gender and BMI. Clinicians must know the usual diameter of the abdominal aorta in order to recognize an aneurysm at an early stage.

Predictive pixel-wise optical encoding: towards single-shot high dynamic range moving object recognition

Conventional low dynamic range (LDR) imaging devices fail to preserve much information for further vision tasks because of the saturation effect. Thus, high dynamic range (HDR) imaging is an important imaging technology in extreme illuminance conditions, which enables a wide range of applications, including photography, autonomous driving, and robotics. Mainstream approaches require multi-shot methods because the conventional camera can only control the exposure globally. Although they perform well on static HDR imaging, they face a challenge with real-time HDR imaging for motional scenes because of the artifact and time latency caused by multi-shot and post-processing. To this end, we propose a framework, termed POE-VP, which achieves single-shot HDR imaging via a pixel-wise optical encoder driven by video prediction. We use highlighted motional license plate recognition as a downstream vision task to demonstrate the performance of POE-VP. From the results of simulation and real scene experiments, we validate that POE-VP outperforms conventional LDR cameras by more than 5 times in recognition accuracy and by more than 200% in information entropy. The dynamic range could reach 120 dB, and the captured data size is verified to be lower than mainstream multi-shot methods by 67%. The running time of POE-VP is also validated to satisfy the needs of high-speed HDR imaging.

Preoperative Immersive Virtual Reality (iVR) Applied to Percutaneous Nephrolithotomy: A Prospective Randomized Clinical Study of Surgical Planning and Clinical Outcomes.

Percutaneous nephrolithotomy (PCNL) is the procedure of choice for the management of complex or large renal stones. A major challenge for the surgeon, however, is the need to assimilate the nearly 2000 static images from a CT scan into a functional mental image to enable surgical planning. Accordingly, we investigated the potential of immersive virtual reality (iVR) to enhance surgical planning and its impact on the outcomes among patients undergoing PCNL. Between 2019-2023, 175 patients undergoing PCNL were pre-operatively randomized into a CT-only group (N=89) or a CT+iVR group (N=86). CT scans were rendered into iVR models that allowed the surgeon not only to visualize and manipulate each patient's relevant anatomy, but also simulate the percutaneous approach to the proposed calyx. Post-operative CT scans were defined as absolute stone-free, <2mm remnants or 2.1-4mm remnants. Pre-operative visualization of the iVR model resulted in a changed calyx of entry in 30% of cases. The CT+iVR group had a significant improvement in absolute stone-free rate (33.70% vs. 20.22%, p=0.043) and overall <4mm remnant rate (62.79% vs. 48.20%, p=0.044). Clavien-Dindo II+IIIa complications were less in the iVR group (3.48% vs. 12.30%, p=0.03). The results were independent of the surgeon's years of PCNL experience. Pre-operative iVR model visualization benefited surgeons and patients alike. From a surgical standpoint, viewing the iVR model resulted in a safer, more effective percutaneous stone removal procedure.

E Pur Si Move! Motion-Based Illusions, Perception and Depiction

ABSTRACT Can static pictures depict motion and temporal properties? This is an open question that is becoming increasingly discussed in both aesthetics and the philosophy of mind. Theorists working on this issue have mainly focused on static pictures of dynamic scenes and streaky images—such as futurists’ paintings or long-exposure photographs. And yet, we could ask: if there is some success in creating an illusory impression of movement in a static image—as is the case in optical illusions of movement, such as Bridget Riley’s Fall (1963: Tate, London), or Kitaoka’s Rotating Snakes Illusion—is this to say that such static images depict movement? As far as I know, no one working on the depiction of motion has specifically and systematically tackled motion-based illusions nor tried to answer this question. This paper considers two cases of optical illusions of movement and concludes that one of them is involved in the depiction of movement. While the declared goal of my analysis is to answer a quite circumscribed question, it is also the occasion to tackle motion-based illusions tout court—to account for the complex visual experiences they elicit and related phenomenology. Moreover, this account has interesting consequences for theorizing depiction and pictorial experience in general. In particular, it constitutes a counterexample to resemblance theories of depiction.

Kinetic Analysis and Metabolism of Poly(Adenosine Diphosphate-Ribose) Polymerase-1-Targeted 18F-Fluorthanatrace PET in Breast Cancer.

The poly(adenosine diphosphate-ribose) polymerase inhibitors (PARPi) have demonstrated efficacy in ovarian, breast, and prostate cancers, but current biomarkers do not consistently predict clinical benefit. 18F-fluorthanatrace (18F-FTT) is an analog to rucaparib, a clinically approved PARPi, and is a candidate biomarker for PARPi response. This study intends to characterize 18F-FTT pharmacokinetics in breast cancer and optimize image timing for clinical trials. A secondary aim is to determine whether 18F-FTT uptake in breast cancer correlates with matched frozen surgical specimens as a reference standard for PARP-1 protein. Methods: Thirty prospectively enrolled women with a new diagnosis of breast cancer were injected with 18F-FTT and imaged dynamically 0-60 min after injection over the chest, with an optional static scan over multiple bed positions starting around 70 min. Kinetic analysis of lesion uptake was performed using blood-pool activity with population radiometabolite corrections. Normal breast and normal muscle reference tissue models were compared with PARP-1 protein expression in 10 patients with available tissue. Plasma radiometabolite concentrations and uptake in tumor and normal muscle were investigated in mouse xenografts. Results: Pharmacokinetics of 18F-FTT were well fit by Logan plot reference region models of reversible binding. However, fits of 2-tissue compartment models assuming negligible metabolite uptake were unstable. Rapid metabolism of 18F-FTT was demonstrated in mice, and similar uptake of radiometabolites was found in tumor xenografts and normal muscle. Tumor 18F-FTT distribution volume ratios relative to normal muscle reference tissue correlated with tissue PARP-1 expression (P < 0.02, n = 10). The tumor-to-normal muscle ratio from a 5-min frame between 50 and 60 min after injection, a potential static scan protocol, closely corresponded to the distribution volume ratio relative to normal muscle and correlated to PARP-1 expression (P < 0.02, n = 10). Conclusion: This study of PARPi analog 18F-FTT showed that uptake kinetics invivo corresponded to expression of PARP-1 and that 18F-FTT quantitation is influenced by radiometabolites that are increasingly present late after injection. Radiometabolites can be controlled by using optimal image acquisition timing or normal muscle reference tissue modeling in dynamic imaging or a tumor-to-normal muscle ratio. Optimal image timing for tumor-to-normal muscle quantification in humans appears to be between 50 and 60 min after injection. Therefore, a clinically practical static imaging protocol commencing 45-55 min after injection may sufficiently balance 18F-FTT uptake with background clearance and radiometabolite interference for quantitative interpretation of PARP-1 expression invivo.

ZnO Nanowire Cold Cathode Hemispherical X‐Ray Sources

AbstractCurved or spherical X‐ray sources are significant for use in intraoperative radiotherapy, adaptive static medical imaging, and high‐throughput industrial inspection, but they are hard to achieve using traditional thermionic cathode point electron sources. In this study, copper (Cu)‐doped zinc oxide (ZnO) nanowires grown on a brass substrate with a designed shape are proposed to achieve cold cathode hemispherical X‐ray sources. The strain‐driven solid–liquid growth model of Cu‐doped ZnO nanowires is proposed, and the oxidation temperature‐dependent and time‐dependent growth characteristics are investigated to optimize the morphologies of ZnO nanowire cold cathodes with a typical turn‐on field of 7.36 MV m−1, a maximum current of 12.54 mA (4.93 mA cm−2) and a uniform field emission image with an area of 2.54 cm2. Hemispherical X‐ray sources formed by Cu‐doped ZnO nanowire field emitters grown on spherical brass alloy and an Al thin film transmission anode target deposited on a hemispherical quartz glass are successfully fabricated, achieving an operating voltage of 39 kV, a dose rate of 240 µGyair s−1 and a projection X‐ray imaging resolution of 2.8 lp mm−1, demonstrating their promising use in a variety of applications.

Radiographic Indicators of Craniocervical Instability: Analyzing Variance of Normative Supine and Upright Imaging in a Healthy Population.

Single-institution retrospective review. To establish baseline ranges and variability of 7 radiographic measurements of the cervical spine in a healthy patient population as potential diagnostic tools for craniocervical instability. Craniocervical instability, common in patients with connective tissue disease such as Ehlers-Danlos Syndrome, often presents with a wide range of symptoms, including neck pain. Current diagnostic methods employ a range of clinical and radiographic features, but diagnostic challenges remain due to missed indications on static imaging and a lack of standardized measurement values and normalized variance. Seventy-two healthy patients with cervical imaging were analyzed. Surgimap software was used to annotate supine computed tomography images, flexion, extension, and neutral x-ray images for measurement. These measurements included the atlanto-dental interval, clival-axial angle, basion-dens interval, basion-axis interval, perpendicular basion to the inferior aspect of C2, also known as Grabb Oakes measurement, and the hard palate to C1 and hard palate to C2. Statistical analysis assessed differences among imaging modalities, and coefficients of variation were calculated for each measurement. Our cohort consisted of a total of 72 patients with a mean age of 64 (SD: 13.54). All measurements except for the basion-axial interval and atlanto-dental interval demonstrated a significant difference between extension and flexion x-ray measurements. clivo-axial angle, hard palate to C1, and hard palate to C2 demonstrated the lowest coefficients of variance across imaging modalities. Understanding normal variance in cervical measurements is invaluable for accurate CCI diagnosis. Using a cohort of healthy patients, this study delineates the distribution and spread of 7 cervical measurements, delineating reference values and variability in these key measurements and highlighting their potential for use as imaging markers for CCI. Level III.

Retraction Note: Three-dimensional face reconstruction of static images and computer standardization issues

Retraction Note: Three-dimensional face reconstruction of static images and computer standardization issues

An Investigation of Metaphoric Perceptions about the Concept of Creative Drama

Purpose: The purpose of this study is to determine whether the perceptions of the participants selected from English teachers about creative drama reflect the general characteristics of creative drama by using metaphor method. Design/Methodology/Approach: Phenomenological research is concerned with how people experience the world at a given time and in a specific context. In other words, phenomenological research aims to describe, understand and interpret the structure of phenomena arising in mind as a result of the interaction of the individuals with the World. “A metaphor form” was used as the data collection tool to determine the perceptions of the teachers about the concept of creative drama. In the form, there is an expression “ creative drama is (a)... because.....”. the participant selection was based on purposive sampling and particiapants were sixty English teacher. Findings: The obtained data were analyzed through content analysis. Results showed that there occured 30 metaphoric expressions and 7 categories. These metaphors were based on game, roleplaying, several themes, creativity, real life, its developmental aspect and wasting time. Highlights: Metaphors direct, shed light and guide our practices. This situation translates into “If a picture is worth a thousand words, a metaphor is worth a thousand pictures; Because a picture just presents a static image, a metaphor provides a mental framework for being about a phenomenon.” (Shuell, 1990) is also clearly reflected. This quote effectively reveals how metaphors are a powerful tool in recording and indicating the general distribution of the human profile and especially the educators themselves.

Report on the AAPM grand challenge on deep generative modeling for learning medical image statistics.

The findings of the 2023 AAPM Grand Challenge on Deep Generative Modeling for Learning Medical Image Statistics are reported in this SpecialReport. The goal of this challenge was to promote the development of deep generative models for medical imaging and to emphasize the need for their domain-relevant assessments via the analysis of relevant imagestatistics. As part of this Grand Challenge, a common training dataset and an evaluation procedure was developed for benchmarking deep generative models for medical image synthesis. To create the training dataset, an established 3D virtual breast phantom was adapted. The resulting dataset comprised about 108000 images of size 512 512. For the evaluation of submissions to the Challenge, an ensemble of 10000 DGM-generated images from each submission was employed. The evaluation procedure consisted of two stages. In the first stage, a preliminary check for memorization and image quality (via the Fréchet Inception Distance [FID]) was performed. Submissions that passed the first stage were then evaluated for the reproducibility of image statistics corresponding to several feature families including texture, morphology, image moments, fractal statistics, and skeleton statistics. A summary measure in this feature space was employed to rank the submissions. Additional analyses of submissions was performed to assess DGM performance specific to individual feature families, the four classes in the training data, and also to identify various artifacts. Fifty-eight submissions from 12 unique users were received for this Challenge. Out of these 12 submissions, 9 submissions passed the first stage of evaluation and were eligible for ranking. The top-ranked submission employed a conditional latent diffusion model, whereas the joint runners-up employed a generative adversarial network, followed by another network for image superresolution. In general, we observed that the overall ranking of the top 9 submissions according to our evaluation method (i) did not match the FID-based ranking, and (ii) differed with respect to individual feature families. Another important finding from our additional analyses was that different DGMs demonstrated similar kinds ofartifacts. This Grand Challenge highlighted the need for domain-specific evaluation to further DGM design as well as deployment. It also demonstrated that the specification of a DGM may differ depending on its intendeduse.

What am I looking at? Graduate student accuracy in identification of anatomic structures/landmarks on swallow imaging.

Speech-language pathologists need to accurately identify structures/landmarks on swallow imaging. Foundational learning begins in graduate training. This study aimed to determine graduate student accuracy at identifying anatomical structures/landmarks during swallow evaluations and to determine if accuracy was predicted by type of imaging, anatomical structure, case type (i.e., normal/abnormal). Researchers recruited first-year graduate speech-language pathology students. Each participant reviewed five static images from lateral radiographic swallow studies and five static images from endoscopic swallow studies across 10 cases. Participants identified key anatomic structures and landmarks by clicking on the structure/landmark within a web-based platform. Two experienced speech-language pathologists reviewed and coded participant responses for accuracy. Sixteen graduate speech-language pathology students participated in a within-subjects design. Overall participant accuracy in identification of structure/landmarks was 69% (range 46%-88%). Binomial logistic regression was performed to study the effects of anatomical structure, case type (i.e., normal/abnormal), and image type on likelihood of participant accuracy in identifying anatomical structures (X2(4) = 143.65, p < 0.001). Only anatomical structure was statistically significant (X2(4) = 187.729, p < 0.001). The model explained 23.2% (Nagelkerke's R squared) of the variance in accuracy and correctly classified 78.4% of cases. Sensitivity was 92.1%, specificity was 47.3%, positive predictive value was 79.84%, and negative predictive value was 72.50%. The area under the ROC curve was 0.754, 95% CI [0.716, 0.791]. Graduate student's ability to correctly identify structures/landmarks overall was lower than desired and accuracy varied per structure. Results have implications for improving graduate student training for identification of structures/landmarks on swallow imaging.

Erosion of the temporal bone by vestibular schwannoma: morphometrics and predictive modeling.

To perform a comprehensive morphometric analysis of vestibular schwannomas (VS) using multimodal imaging, focusing on the relationship between tumor characteristics and internal acoustic canal (IAC) changes. We analyzed a cohort of patients undergoing radiosurgery for VS, utilizing high-definition MRI and bone CT for detailed anatomical assessment. Image co-registration and fusion techniques were employed to examine VS and IAC dimensions. Advanced statistical methods, including logistic regression, were applied to identify patterns of IAC dilation and establish predictive indicators for these morphological changes. The study included 659 patients (51.1% female, mean age 56.37years) with evenly distributed tumor lateralization. Koos grades were I (22.9%), II (29.9%), III (38.2%), IVa (8.9%), and IVb (0.3%). Most tumors (90.9%) extended both inside and outside the IAC. Ipsilateral IAC (IIAC) dimensions were significantly larger than contralateral, with IIAC volume 49% greater (p < .0001). Higher Koos grades correlated with increased intra-canalicular lesion volume (icLV), which was strongly associated with IIAC size. Logistic regression identified icLV as the strongest predictor of IIAC dilation (AUC = 0.7674, threshold = 137.52 mm3). The icLV appears central to the pathophysiological development of VS and its impact on IAC anatomy. While limited by a selective patient base and static imaging data, these findings enhance the understanding of VS-IAC interactions, offering insights for improved clinical management and further research.

Quantitative anatomy of the infraspinatus muscle in the human fetus.

The study presents one of the six scapulohumeral muscles, which occupies most of the osteofibrous infraspinatus compartment. Along with the supraspinatus, teres minor and subscapularis muscles, the infraspinatus muscle contributes to the rotator cuff. It protects the posterior aspect of the articular capsule of the shoulder joint, adducts and externally rotates the arm. The aim of the study was to perform the quantitative analysis of the infraspinatus muscle in human fetuses and to elaborate growth dynamics for its morphometric parameters. Using anatomical dissection, digital image analysis (NIS Elements AR3.0) and statistics (Student's t-test, regression analysis), the vertical, transverse and oblique diameters, muscle circumference and projection surface area of the infraspinatus muscle were measured in 36human fetuses of both sexes (17♂, 19♀) aged 18-30weeks. The infraspinatus muscle revealed neither sex nor laterality differences. All examined morphometric parameters of the infraspinatus muscle increased commensurately in accordance with the following linear functions: y=-4.024 + 0.903×Age ± 0.621 (R²=0.96) for transverse diameter, y=-3.089 + 1.321×Age ± 0.897 (R²=0.97) for vertical diameter, y=-1.161 + 0.632×Age ± 0.444 (R²=0.97) for oblique diameter, y=-13.575 + 3.851×Age ± 1.938 (R²=0.98) for muscle circumference and y=-293.512 + 23.228×Age ±19.650 (R²=0.95) for projection surface area.

High-resolution motion compensation for brain PET imaging using real-time electromagnetic motion tracking.

Substantial improvements in spatial resolution in brain positron emission tomography (PET) scanners have greatly reduced partial volume effect, making head movement the main source of image blur. To achieve high-resolution PET neuroimaging, precise real-time estimation of both head position and orientation is essential for accurate motion compensation. A high-resolution electromagnetic motion tracking (EMMT) system with an event-by-event motion correction is developed for PET-CTscanners. EMMT is comprised of a source, an array of sensors, and a readout electronic unit (REU). The source acts as a transmitter and emits an EM dipole field. It is placed in close proximity to the sensor array and detects changes in EM flux density due to sensor movement. The REU digitizes signals from each sensor and captures precise rotational and translational movements in real time. Tracked motion in the EMMT coordinate system is synchronized with the PET list-mode data and transformed into the scanner coordinate system by locating paired positions in both systems. The optimal rigid motion is estimated using singular value decomposition. The rigid motion and depth-of-interaction (DOI) parallax effect are corrected by event-by-event rebinning of mispositioned lines-of-response (LORs). We integrated the EMMT with our recently developed ultra-high resolution Prism-PET prototype brain scanner and a commercial Siemens Biograph mCT PET-CT scanner. We assessed the imaging performance of the Prism-PET/EMMT system using multi-frame motion of point sources and phantoms. The mCT/EMMT system was validated using a set of point sources attached to both a mannequin head and a human volunteer, for simulating multiframe and continuous motions, respectively. Additionally, a human subject for [18F]MK6240 PET imaging wasincluded. The tracking accuracy of the Prism-PET/EMMT system was quantified as a root-mean-square (RMS) error of 0.49 for 100 axial rotations, and an RMS error of 0.15 mm for 100 mm translations.The percent difference (%diff) in average full width at half maximum (FWHM) of point source between motion-corrected and static images, within a motion range of and 10 mm from the center of the scanner's field-of-view (FOV), was 3.9%. The measured recovery coefficients of the 2.5-mm diameter sphere in the activity-filled partial volume correction phantom were 23.9%, 70.8%, and 74.0% for the phantom with multi-frame motion, with motion and motion compensation, and without motion, respectively. In the mCT/EMMT system, the %diff in average FWHM of point sources between motion-corrected and static images, within a motion range of and 10 mm from the center of the FOV, was 14%. Applying motion correction to the [18F]MK6240 PET imaging reduced the motion-induced spill-in artifact in the lateral ventricle region, lowering its standardized uptake value ratio (SUVR) from 0.70 to 0.34. The proposed EMMT system is a cost-effective, high frame-rate, and none-line-of-sight alternative to infrared camera-based tracking systems and is capable of achieving high rotational and translational tracking accuracies for mitigating motion-induced blur in high-resolution brain dedicated PETscanners.

Feasibility of ultra-low activity 18F-FDG PET/CT imaging in children.

To investigate the feasibility of pediatric 18F-FDG total-body PET/CT imaging with an ultra-low activity and explore an optimized acquisition time range. A total of 38 pediatric patients were prospectively enrolled and underwent dynamic total-body PET/CT imaging using ultra-low 18F-FDG activity (0.37 MBq/kg). The 60-minute list-mode raw data were acquired and then reconstructed as static PET images by using 50-51, 50-52, 50-53, 50-54, 50-55, 50-58, 50-60, and 45-60 minutes data, which were noted as G1, G2, G3, G4, G5, G8, G10, and G15, respectively. Image qualities were subjectively evaluated using the Likert scale and were objectively evaluated by the quantitative metrics including standard uptake value (SUV), signal-to-noise ratio (SNR), target-to-background ratio (TBR), and contrast-to-noise ratio (CNR). The injected activity of FDG was 13.38 ± 5.68 MBq (4.40-28.16 MBq) and produced 0.58 ± 0.19 mSv (0.29-1.04 mSv) of effective dose. The inter-reader agreement of subjective image quality was excellent (kappa = 0.878; 95% CI, 0.845-0.910). The average scores of image quality for G1-G15 were 1.10 ± 0.20, 2.03 ± 0.26, 2.66 ± 0.35, 3.00 ± 0.27, 3.32 ± 0.34, 4.25 ± 0.30, 4.49 ± 0.36, and 4.70 ± 0.37, respectively. All image scores are above 3 and all lesions are detectable starting from G8. SNRs of backgrounds, TBRs, and CNRs were significant differences from the control group before G8 (all P < 0.05). The image quality of the 8 min acquisition for pediatric 18F-FDG total-body PET/CT with an ultra-low activity could meet the diagnostic requirements. This study confirms the feasibility of ultra-low dose PET imaging in children, and its methods and findings may guide clinical practice. pediatric patients will benefit from reduced radiation doses.

Immuno-PET Imaging of EGFR with 64Cu-NOTA Panitumumab in Subcutaneous and Metastatic Nonsmall Cell Lung Cancer Xenografts.

Objective: About 65-90% of nonsmall cell lung cancer (NSCLC) express the epithelial growth factor receptor (EGFR) as a transmembrane protein that is activated by binding of specific ligands, including epidermal growth factor and transforming growth factor α (TGFα). Identifying EGFR as an oncogene has led to the development of anticancer therapeutics directed against EGFR, including the full-length human IgG2 monoclonal antibody panitumumab. The main goal of the present study was to investigate 64Cu-labeled panitumumab with immuno-PET in subcutaneous and metastatic EGFR-positive NSCLC xenografts. Methods: Bifunctional chelating agent 2-S-(4-isothiocyanatobenzyl)-1,4,7-triazacyclo-nonane-1,4,7-triacetic acid (NOTA-NCS) was attached to panitumumab. The number of chelators per panitumumab was determined using matrix-assisted laser desorption/ionization (MALDI) mass spectroscopy. The incorporation efficiency of 64Cu into NOTA-panitumumab was measured by using radio-TLC. EGFR-expressing epithelial-like H1299-luc+ NSCLC cells were used for in vitro and in vivo experiments. Cell uptake of [64Cu]Cu-NOTA-panitumumab was measured in the presence and absence of panitumumab. Subcutaneous and metastatic H1299-luc tumor models were grown in male NSG mice. The presence of tumors at lung and metastatic sites was analyzed by [18F]FLT PET. Immuno-PET with [64Cu]Cu-NOTA-panitumumab was performed as static PET imaging at 2, 24, and 48 h postinjection in both tumor models. Proof-of-target was confirmed by blocking experiments with panitumumab. Detailed ex vivo biodistribution experiments were performed in both animal tumor models to confirm biodistribution profiles obtained by immuno-PET imaging. Results: MALDI analysis confirmed the attachment of ∼1.5 NOTA per antibody. Radiolabeling efficiency with [64Cu]CuCl2 was 93.8 ± 5.7% and a molar activity of 0.65 MBq/μg. Cellular uptake studies with [64Cu]Cu-NOTA-panitumumab in H1299 cells demonstrated increasing uptake over time, reaching 29.1 ± 2.9% radioactivity(Bq)/mg protein (n = 3) and plateauing at 45 min. Addition of 25 μg of panitumumab reduced radioligand uptake to 1.22 ± 0.06% radioactivity/mg protein (n = 3). PET imaging revealed high uptake of [64Cu]Cu-NOTA-panitumumab in subcutaneous tumors: Standardized uptake values (SUV)mean reached 4.70 ± 0.42 and 5.37 ± 0.40 (n = 5) after 24 and 48 h postinjection, respectively. Administration of 1 mg panitumumab reduced tumor uptake significantly to 1.94 ± 0.22 and 1.66 ± 0.08 (n = 4; p < 0.001). In the metastatic model, the following SUVmean were analyzed from liver and lung lesions: 5.55 ± 0.34 and 6.28 ± 0.46 (both n = 23 lesions from 6 mice) after 24 and 48 h postinjection, which was also significantly reduced to 2.53 ± 0.39 and 2.31 ± 0.15 (both n = 16 lesions from 4 mice; p < 0.001) after injection of 1 mg panitumumab. Detailed ex vivo biodistribution confirmed immuno-PET analysis in both models. Panitumumab reduced radioactivity uptake into subcutaneous tumors from 11.01 ± 0.72 (n = 4) to 3.67 ± 0.33% ID/g (n = 5; p < 0.001), and in metastatic liver lesions from 29.44 ± 8.14 (n = 4) to 8.35 ± 1.30% ID/g (n = 5; p < 0.001), respectively. Conclusions: [64Cu]Cu-NOTA-panitumumab was successfully used for immuno-PET imaging of EGFR-expressing subcutaneous and metastatic NSCLC tumors. This result represents the basis for developing radiotheranostics for targeting EGFR in cancers and for selecting the right patients for the right treatment at the right time.

Gaze behaviors during free viewing revealed differences in visual salience processing across four major psychiatric disorders: a mega-analysis study of 1012 individuals.

Aberrant salience processing has been proposed as a pathophysiological mechanism underlying psychiatric symptoms in patients with schizophrenia. The gaze trajectories of individuals with schizophrenia have been reported to be abnormal when viewing an image, suggesting anomalous visual salience as one possible pathophysiological mechanism associated with psychiatric diseases. This study was designed to determine whether visual salience is affected in individuals with schizophrenia, and whether this abnormality is unique to patients with schizophrenia. We examined the gaze behaviors of 1012 participants recruited from seven institutes (550 healthy individuals and 238, 41, 50 and 133 individuals with schizophrenia, bipolar disorder, major depressive disorder and autism spectrum disorder, respectively) when they looked at stationary images as they liked, i.e., free-viewing condition. We used an established computational model of salience maps derived from low-level visual features to measure the degree to which the gaze trajectories of individuals were guided by visual salience. The analysis revealed that the saliency at the gaze of individuals with schizophrenia were higher than healthy individuals, suggesting that patients' gazes were guided more by low-level image salience. Among the low-level image features, orientation salience was most affected. Furthermore, a general linear model analysis of the data for the four psychiatric disorders revealed a significant effect of disease. This abnormal salience processing depended on the disease and was strongest in patients with schizophrenia, followed by patients with bipolar disorder, major depressive disorder, and autism spectrum disorder, suggesting a link between abnormalities in salience processing and strength/frequency for psychosis of these disorders.

Bivariate BMM-based hybrid domain image watermark detector

Robustness, imperceptibility, and watermark capacity are three indispensable and contradictory properties for any image watermarking systems. It is a challenging work to achieve the balance among the three important properties. In this paper, by using the bivariate Beta mixture model (Bivariate BMM), we present a statistical image watermark scheme in nonsubsampled Contourlet transform (NSCT)-fractional order Jacobi Fourier moments (FJFMs) amplitude hybrid domain. The whole watermarking algorithm includes two parts: watermark embedding and detection. NSCT is firstly performed on host image to obtain the frequency subbands, and the NSCT subbands are divided into non overlapping blocks. Then, the significant NSCT domain blocks are selected using local binary patterns (LBP). Meanwhile, for each selected NSCT coefficient block, FJFMs are calculated to obtain the NSCT-FJFMs amplitude. Finally, watermark signals are inserted into the amplitude hybrid domain of NSCT-FJFMs. In order to detect accurately watermark signal, the statistical characteristics of NSCT-FJFMs magnitudes are analyzed in detail. Then, NSCT-FJFMs magnitudes are described statistically by Bivariate BMM, which can simultaneously capture the marginal distribution and strong dependencies of NSCT-FJFMs magnitudes. Also, Bivariate BMM parameters are estimated accurately by the rough-enhanced-Bayes mixture estimation & expectation–maximization (REBMIX&EM) approach. Finally, a statistical watermark detector based on the locally optimum (LO) decision rule and Bivariate BMM is developed in NSCT-FJFMs magnitude hybrid domain. Also, the closed-form expressions on the LO statistic is derived and the receiver operating characteristic (ROC) about our detector is analyzed. Extensive experimental results show the superiority of the proposed image watermark detector over some state-of-the-art statistical watermarking methods.