Characterizing and Monitoring Suspected Underground Nuclear Sites with VideoSAR.
Abstract not provided.
Dauphin, Stephen Michael↗
SEARCH · Engineering Papers
Results for “SUSPECT”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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A New Mask for An Old Suspect: Testing the Sensitivity of the Galactic Center Excess to the Point Source Mask
The Fermi-LAT collaboration has recently released a new point source catalog, referred to as 4FGL. For the first time, we perform a template fit using information from this new catalog and find that the Galactic center excess is still present. On the other hand, we find that a wavelet-based search for point sources is highly sensitive to the use of the 4FGL catalog: no excess of bright regions on small angular scales is apparent when we mask out 4FGL point sources. We postulate that the 4FGL catalog contains the large majority of bright point sources that have previously been suggested to account for the excess in gamma rays detected at the Galactic center in Fermi-LAT data. Furthermore, after identifying which bright sources have no known counterpart, we place constraints on the luminosity function necessary for point sources to explain the smooth emission seen in the template fit.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Notification of Newly-Identified or Suspected Release at Sandia National Laboratories New Mexico (SNL/NM).
Abstract not provided.
Reiser, Anita S.↗
Assessment Report on the Newly-Identified or Suspected Release of Hazardous Waste at Building 897.
Abstract not provided.
Reiser, Anita S.↗
Assessment Report on the Newly-Identified or Suspected Release of Hazardous Waste at Building 897 Sandia National Laboratories/New Mexico (SNL/NM).
Abstract not provided.
Reiser, Anita S.↗
Modeling the use of mobile modular gas samplers in near-field detection
The Wireless Independent Noble Gas Sampler (WINGS) is a mobile, modular gas sampling system designed for use in low infrastructure environments. In the case of a suspected underground nuclear explosion (UNE), WINGS units could be deployed to detect noble gases emanating from the suspected explosion site or identify gases originating from another source entering the local area from offsite. In conclusion, this work uses the atmospheric transport modeling tool inline WRF-HYSPLIT to test the effectiveness of WINGS units around a suspected UNE site as a function of sampler density and distance from the emission point of gases from a UNE.
Air sampling↗
Attitudes Toward Blinding of Peer Review and Perceptions of Efficacy Within a Small Biomedical Specialty
Purpose: Peer reviewers' knowledge of author identity may influence review content, quality, and recommendations. Therefore, the International Journal of Radiation Oncology, Biology, Physics (“Red Journal”) implemented double-blinded peer review in 2011. Given the relatively small size of the specialty and the high frequency of preliminary abstract presentations, we sought to evaluate attitudes, the efficacy of blinding, and the potential impact on the disposition of submissions. Methods and Materials: In May through August 2012, all Red Journal reviewers and 1 author per manuscript completed questionnaires regarding demographics, attitudes, and perceptions of success of blinding. We also evaluated correlates of the outcomes of peer review. Results: Questionnaires were received from 408 authors and 519 reviewers (100%). The majority of respondents favored double blinding; 6% of authors and 13% of reviewers disagreed that double blinding should continue in the Red Journal. In all, 50% of the reviewers did not suspect the identity of the author of the paper that they reviewed; 19% of reviewers believed that they could identify the author(s), and 31% suspected that they could. Similarly, 23% believed that they knew the institution(s) from which the paper originated, and 34% suspected that they did. Among those who at least suspected author identity, 42% indicated that prior presentations served as a clue, and 57% indicated that literature referenced did so. Of those who at least suspected origin and provided details (n=133), 13% were entirely incorrect. Rejection was more common in 2012 than 2011, and submissions from last authors with higher H-indices (>21) were more likely to survive initial review, without evidence of interactions between submission year and author gender or H-index. Conclusions: In a relatively small specialty in which preliminary research presentations are common and occur in a limited number of venues, reviewers are often familiar with research findings and suspect author identity even when manuscript review is blinded. Nevertheless, blinding appears to be effective in many cases, and support for continuing blinding was strong.
62 RADIOLOGY AND NUCLEAR MEDICINE↗
Value of Surveillance Studies for Patients With Stage I to II Diffuse Large B-Cell Lymphoma in the Rituximab Era
Background: The role of surveillance studies in limited-stage diffuse large B-cell lymphoma (DLBCL) in the rituximab era has not been well defined. We sought to evaluate the use of imaging (computed tomography [CT] and positron emission tomography [PET]-CT) scans and lactate dehydrogenase (LDH) in surveillance of patients with stage I to II DLBCL. Methods: A retrospective analysis was performed of patients who received definitive treatment between 2000 and 2013. Results: One hundred sixty-two consecutive patients with stage I to II DLBCL were treated with chemotherapy +/− rituximab, radiation, or combined modality therapy. The 5-year rates of overall survival (OS) and freedom from progression (FFP) were 81.2% and 80.8%, respectively. Of the 162 patients, 124 (77%) were followed up with at least 1 surveillance PET scan beyond end-of-treatment scans; of those, 94 of 124 (76%) achieved a complete metabolic response on PET scan after completion of chemotherapy, and this was associated with superior FFP (P=.01, HR=0.3) and OS (P=.01, HR 0.3). Eighteen patients experienced relapse after initial response to therapy. Nine relapses were initially suspected by surveillance imaging studies (8 PET, 1 CT), and 9 were suspected clinically (5 by patient-reported symptoms and 4 by symptoms and physical examination). No relapses were detected by surveillance LDH. The median duration from initiation of treatment to relapse was 14.3 months among patients with relapses suspected by imaging, and 59.8 months among patients with relapses suspected clinically (P=.077). There was no significant difference in OS from date of first therapy or OS after relapse between patients whose relapse was suspected by imaging versus clinically. Thirteen of 18 patients underwent successful salvage therapy after relapse. Conclusions: A complete response on PET scan immediately after initial chemotherapy is associated with superior FFP and OS in stage I to II DLBCL. The use of PET scans as posttreatment surveillance is not associated with a survival advantage. LDH is not a sensitive marker for relapse. Our results argue for limiting the use of posttreatment surveillance in patients with limited-stage DLBCL.
62 RADIOLOGY AND NUCLEAR MEDICINE↗
Conical ultrashort echo time (UTE) MRI in the evaluation of pediatric acute appendicitis
Purpose: Magnetic resonance imaging (MRI) sequences with conical k-space trajectories are able to decrease motion artifacts while achieving ultrashort echo times (UTE). We assessed the performance of free-breathing conical UTE MRI in the evaluation of the pediatric pelvis for suspected appendicitis. Methods: Our retrospective review of 84 pediatric patients who underwent MRI for suspected appendicitis compared three contrast-enhanced sequences: free-breathing conical UTE, breath-hold three-dimensional (3D) spoiled gradient echo (BH-SPGR), and free-breathing high-resolution 3D SPGR (FB-SPGR). Two radiologists performed blinded and independent evaluations of each sequence for image quality (four point scale), anatomic delineation (four point scale), and diagnostic confidence (five point scale). Subsequently, the three sequences were directly compared for overall image quality (− 3 to + 3 scale). Scores were compared using Kruskal–Wallis and Wilcoxon signed-rank tests. Results: UTE demonstrated significantly better perceived signal-to-noise ratio (SNR) and fewer artifacts than BH-SPGR and FB-SPGR (means of 3.6 and 3.4, 3.4 and 3.2, 3.1 and 2.7, respectively; p < 0.0006). BH-SPGR and FB-SPGR demonstrated significantly better contrast than UTE (means of 3.6, 3.4, and 3.2, respectively; p < 0.03). In the remaining categories, UTE performed significantly better than FB-SPGR (p < 0.00001), while there was no statistical difference between UTE and BH-SPGR. Direct paired comparisons of overall image quality demonstrated the readers significantly preferred UTE over both BH-SPGR (mean + 0.5, p < 0.00001) and FB-SPGR (mean + 1.2, p < 0.00001). Conclusions: In the evaluation of suspected appendicitis, free-breathing conical UTE MRI performed better in the assessed metrics than FB-SPGR. When compared to BH-SPGR, UTE demonstrated superior perceived SNR and fewer artifacts.
62 RADIOLOGY AND NUCLEAR MEDICINE↗
Using Multiple Geophysical Methods to Refine a Stratigraphic Conceptual Site Model at a Nuclear Waste Site
At contaminated sites, there is a critical reliance on conceptual site models of which a key component is the geologic framework model (GFM), which is used to build predictive fate and transport modeling in support of remediation goals. Here, we detail an ongoing study at a nuclear waste site (Hanford Site, Washington, USA) where surface geophysical methods were used to complement existing borehole information and to help site new boreholes to update and refine the GFM. Ground-based electrical resistivity tomography (ERT), time-domain electromagnetics (TEM), and seismic data was acquired on the Hanford Site’s Central Plateau, where the presence of a hydraulically transmissive subsurface feature, or paleochannel, was suspected but uncertain based on contaminant concentrations at sparsely located boreholes. To assess and compare ERT, TEM, and seismic geophysical datasets, co-located data was acquired in an area where the existing GFM was more certain. Surrounding the suspected paleochannel, ERT and seismic refraction tomography showed similar subsurface structures consistent with a channelized feature. While TEM interpretation was limited in the suspected paleochannel area due to a thick resistive top layer and high electromagnetic noise, TEM showed greater utility in a different area where these factors were less prevalent. Based on the results of quasi-3D ERT inversions, we propose updates to the GFM, including identifying a paleochannel. Further, we evaluate the utility of geophysical methods and examine lessons learned that will be used as a basis for continued characterization efforts to support site management decisions and implementation efforts.
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Ten-Year Outcomes: The Clinical Utility of Single Photon Emission Computed Tomography/Computed Tomography Capromab Pendetide (Prostascint) in a Cohort Diagnosed With Localized Prostate Cancer
Purpose: To evaluate the clinical utility of capromab pendetide imaging with single photon emission computed tomography coregistration with computed tomography (SPECT/CT) in primary prostate cancer (CaP) for pretreatment prognostic staging and localization of biologic target volumes (BTV) for individualized image-guided radiotherapy dose escalation (IGRT-DE). Methods and Materials: Patients consecutively presenting for primary radiotherapy (February 1997 to December 2002), having a clinical diagnosis of localized CaP, were evaluated for tumor stage using conventional staging and SPECT/CT (N = 239). Distant metastatic uptake (mets) were identified by SPECT/CT in 22 (9.2%). None of the suspected mets could be clinically confirmed. Thus, all subjects were followed without alteration in disease management. The SPECT/CT pelvic images defined BTV for IGRT-DE (+150% brachytherapy dose) without (n = 150) or with (n = 89) external radiation of 45 Gy. The National Comprehensive Cancer Network criteria defined risk groups (RG). The median survivor follow-up was 7 years. Biochemical disease-free survival (bDFS) was reported by clinical nadir +2 ng/mL (CN+2) criteria. Statistical analyses included Kaplan-Meier, multivariate analysis, and Concordance-index models. Results: At 10-year analyses, overall survival was 84.8% and bDFS was 84.6%. With stratification by RG, CN+2 bDFS was 93.5% for the low-RG (n = 116), 78.7% for the intermediate-RG (n = 94), and 68.8% for the high-RG (n = 29), p = 0.0002. With stratification by pretreatment SPECT/CT findings, bDFS was 65.5% in patients with suspected mets (n = 22) vs. 86.6% in patients with only localized uptake (n = 217), p = 0.0014. CaP disease-specific survival (DSS) was 97.7% for the cohort. With stratification by SPECT/CT findings, DSS was 86.4% (with suspected mets) vs. 99.0% (localized only), p = 0.0001. Using multivariate analysis, the DSS hazard ratio for SPECT/CT findings (mets vs. localized) was 3.58 (p = 0.0026). Concordance-index tests, based on all data, by CN+2 bDFS criteria were 0.710 for RG alone and 0.773 for SPECT/CT + RG. Conclusions: Through long-term outcomes we demonstrate statistically significant bDFS and DSS predictive value for pretreatment capromab pendetide SPECT/CT imaging in primary CaP. Dual clinical utility is demonstrated, using SPECT/CT to define BTV for individualized IGRT-DE.
62 RADIOLOGY AND NUCLEAR MEDICINE↗
Malware analysis and recovery
A system and method detects malware by processing notifications from an intrusion detection system and baseline snapshots from an image capture utility. The image capture utility constructs an image of the suspected malware intrusion and links the suspected malware intrusion to the baseline snapshots. The system and method propagates the image of the suspected malware intrusion across multiple networks before it distinguishes malicious code, device state, and files from benign code, device state, and files. Some systems and methods include a malware recovery system that executes machine learning instructions and heuristics to revert a client and/or a remote server to one or more baseline snapshots.
Smith, Jared M.↗
Tau Positron Emission Tomography for Predicting Dementia in Individuals With Mild Cognitive Impairment
An accurate prognosis is especially pertinent in mild cognitive impairment (MCI), when individuals experience considerable uncertainty about future progression. To evaluate the prognostic value of tau positron emission tomography (PET) to predict clinical progression from MCI to dementia. This was a multicenter cohort study with external validation and a mean (SD) follow-up of 2.0 (1.1) years. Data were collected from centers in South Korea, Sweden, the US, and Switzerland from June 2014 to January 2024. Participant data were retrospectively collected and inclusion criteria were a baseline clinical diagnosis of MCI; longitudinal clinical follow-up; a Mini-Mental State Examination (MMSE) score greater than 22; and available tau PET, amyloid-β (Aβ) PET, and magnetic resonance imaging (MRI) scan less than 1 year from diagnosis. A total of 448 eligible individuals with MCI were included (331 in the discovery cohort and 117 in the validation cohort). None of these participants were excluded over the course of the study. Exposures included Tau PET, Aβ PET, and MRI. Positive results on tau PET (temporal meta–region of interest), Aβ PET (global; expressed in the standardized metric Centiloids), and MRI (Alzheimer disease [AD] signature region) was assessed using quantitative thresholds and visual reads. Clinical progression from MCI to all-cause dementia (regardless of suspected etiology) or to AD dementia (AD as suspected etiology) served as the primary outcomes. The primary analyses were receiver operating characteristics. In the discovery cohort, the mean (SD) age was 70.9 (8.5) years, 191 (58%) were male, the mean (SD) MMSE score was 27.1 (1.9), and 110 individuals with MCI (33%) converted to dementia (71 to AD dementia). Only the model with tau PET predicted all-cause dementia (area under the receiver operating characteristic curve [AUC], 0.75; 95% CI, 0.70-0.80) better than a base model including age, sex, education, and MMSE score (AUC, 0.71; 95% CI, 0.65-0.77; P = .02), while the models assessing the other neuroimaging markers did not improve prediction. In the validation cohort, tau PET replicated in predicting all-cause dementia. Compared to the base model (AUC, 0.75; 95% CI, 0.69-0.82), prediction of AD dementia in the discovery cohort was significantly improved by including tau PET (AUC, 0.84; 95% CI, 0.79-0.89; P < .001), tau PET visual read (AUC, 0.83; 95% CI, 0.78-0.88; P = .001), and Aβ PET Centiloids (AUC, 0.83; 95% CI, 0.78-0.88; P = .03). In the validation cohort, only the tau PET and the tau PET visual reads replicated in predicting AD dementia. In this study, tau-PET showed the best performance as a stand-alone marker to predict progression to dementia among individuals with MCI. This suggests that, for prognostic purposes in MCI, a tau PET scan may be the best currently available neuroimaging marker.
59 BASIC BIOLOGICAL SCIENCES↗
Reader agreement and accuracy of ultrasound features for hepatic steatosis
Purpose: The purpose of the study is to assess the reader agreement and accuracy of eight ultrasound imaging features for classifying hepatic steatosis in adults with known or suspected hepatic steatosis. Methods: This was an IRB-approved, HIPAA-compliant prospective study of adult patients with known or suspected hepatic steatosis. All patients signed written informed consent. Ultrasound images (Siemens S3000, 6C1HD, and 4C1 transducers) were acquired by experienced sonographers following a standard protocol. Eight readers independently graded eight features and their overall impression of hepatic steatosis on ordinal scales using an electronic case report form. Duplicated images from the 6C1HD transducer were read twice to assess intra-reader agreement. Intra-reader, inter-transducer, and inter-reader agreement were assessed using intraclass correlation coefficients (ICC). Features with the highest intra-reader agreement were selected as predictors for dichotomized histological steatosis using Classification and Regression Tree (CART) analysis, and the accuracy of the decision rule was compared to the accuracy of the radiologists’ overall impression. Results: 45 patients (18 males, 27 females; mean age 56 ± 12 years) scanned from September 2015 to July 2016 were included. Mean intra-reader ICCs ranged from 0.430 to 0.777, inter-transducer ICCs ranged from 0.228 to 0.640, and inter-reader ICCs ranged from 0.014 to 0.561. The CART decision rule selected only large hepatic vein blurring and achieved similar accuracy to the overall impression (74% to 75% and 68% to 72%, respectively). Conclusions: Large hepatic vein blurring, liver–kidney contrast, and overall impression provided the highest reader agreement. Large hepatic vein blurring may provide the highest classification accuracy for dichotomized grading of hepatic steatosis.
62 RADIOLOGY AND NUCLEAR MEDICINE↗
Ultrasound versus computed tomography for the detection of ureteral calculi in the pediatric population: a clinical effectiveness study
Objective: To determine the diagnostic performance of ultrasound for diagnosing ureteral calculi in children using a clinical effectiveness approach. Methods: Billing records and imaging reports were used to identify children (≤ 18 years old) evaluated for suspected urolithiasis using ultrasound between March 2012 and March 2017. Patients without unenhanced CT within 24 h (reference standard) were excluded. Imaging (ultrasound and CT) reports were reviewed for presence, number, size, and location of calculi. Diagnostic performance of ultrasound (versus CT) was calculated on an individual ureter basis both by direct calculus visualization as well as direct visualization combined with suspected presence of ureteral stone based on indirect ultrasound findings. Results: 41 ureteral calculi were present in 38 of 69 (55.1%) patients. Mean patient age was 14.7 ± 3.6 years, and 35 of 69 (51%) patients were boys. Based on direct calculus visualization, ultrasound had a sensitivity of 12.8% (95% CI 5.6–26.7%), specificity of 100% (95% CI 96.3–100%), positive predictive value (PPV) of 100% (95% CI 56.6–100%), and negative predictive value (NPV) of 74.4% (95% CI 66.4–81.1%). When ultrasound examinations reported as suspicious for ureteral calculi based on indirect findings also were considered positive, ultrasound had a sensitivity of 41.0% (95% CI 27.1–56.6%), specificity of 95.0% (95% CI 88.7–97.8%), PPV of 76.2% (95% CI 54.9–89.4%), and NPV of 80.3% (95% CI 72.2–86.5%). Conclusions: In clinical practice, ultrasound has low sensitivity for directly visualizing ureteral calculi subsequently identified by CT, although sensitivity improves when considering suspicious examinations as positive.
62 RADIOLOGY AND NUCLEAR MEDICINE↗
Molecular Imaging of Cardiac Amyloidosis
Purpose of Review: The aim of this review is to give an update on the molecular imaging tools currently available as well as to discuss the potential roles and limitations of molecular imaging in cardiac amyloidosis. Recent Findings: Molecular imaging plays a central role in the evaluation of patients with suspected cardiac amyloidosis. It can be used to diagnose and distinguish between the different types of cardiac amyloidosis. The diagnostic properties of bone scintigraphy are such that it allows reliable diagnosis of transthyretin cardiac amyloidosis without the need of endomyocardial biopsy in a significant proportion of patients. Furthermore, molecular tracers assessing amyloid plaque burden and sympathetic innervation may be useful for the non-invasive evaluation diagnosis and risk stratification of patients with suspected cardiac amyloidosis. Summary: Cardiac amyloidosis is an under-recognized cause of left ventricular hypertrophy and heart failure in the elderly. The role of molecular imaging in cardiac amyloidosis is expected to grow considering the arrival of new therapies and molecular imaging probes.
62 RADIOLOGY AND NUCLEAR MEDICINE↗
A multifunctional CT technology: Reality or illusion for patient risk assessment?
A high-speed, multi-slice coronary computed tomography (CT) imaging has emerged as a promising or clinically available multifunctional technique for the assessment of myocardial ischemia, viability, ischemia-induced cardiac dysfunction, and coronary atherosclerotic alterations in patients with suspected or known coronary artery disease. Despite several technical issues remain to be resolved, cardiac CT imaging will have a reality as a multifunctional modality for guiding physicians in better decision-making for favorable clinical outcomes in patients with suspected coronary artery disease, provided that this imaging technology can contribute to characterization and localization of high-risk coronary atherosclerosis in combination with the quantitative evaluation of functional myocardial ischemia.
62 RADIOLOGY AND NUCLEAR MEDICINE↗