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Objectives: To describe the findings of incidental asymptomatic COVID-19 infection on FDG PET-CT using a case–control design. Methods: Incidental pulmonary findings suspicious of asymptomatic COVID-19 infection on FDG PET-CT were classified as a confirmed (positive RT-PCR test) or suspected case (no/negative RT-PCR test). Control cases were identified using a 4:1 control:case ratio. Pulmonary findings were re-categorised by two reporters using the BSTI classification. SUV metrics in ground glass opacification (GGO)/consolidation (where present), background lung, intrathoracic nodes, liver, spleen and bone marrow were measured. Results: 7/9 confirmed and 11/15 suspected cases (COVID-19 group) were re-categorised as BSTI 1 (classic/probable COVID-19) or BSTI 2 (indeterminate COVID-19); 0/96 control cases were categorised as BSTI 1. Agreement between two reporters using the BSTI classification was almost perfect (weighted κ = 0.94). SUVmax GGO/consolidation (5.1 vs 2.2; p < 0.0001) and target-to-background ratio, normalised to liver SUVmean (2.4 vs 1.0; p < 0.0001) were higher in the BSTI 1 & 2 group vs BSTI 3 (non-COVID-19) cases. SUVmax GGO/consolidation discriminated between the BSTI 1 & 2 group vs BSTI 3 (non-COVID-19) cases with high accuracy (AUC = 0.93). SUV metrics were higher (p < 0.05) in the COVID-19 group vs control cases in the lungs, intrathoracic nodes and spleen. Conclusion: Asymptomatic COVID-19 infection on FDG PET-CT is characterised by bilateral areas of FDG avid (intensity > x2 liver SUVmean) GGO/consolidation and can be identified with high interobserver agreement using the BSTI classification. There is generalised background inflammation within the lungs, intrathoracic nodes and spleen. Advances in knowledge: Incidental asymptomatic COVID-19 infection on FDG PET-CT, characterised by bilateral areas of ground glass opacification and consolidation, can be identified with high reproducibility using the BSTI classification. The intensity of associated FDG uptake (>x2 liver SUVmean) provides high discriminative ability in differentiating such cases from pulmonary findings in a non-COVID-19 pattern. Asymptomatic COVID-19 infection causes a generalised background inflammation within the mid-lower zones of the lungs, hilar and central mediastinal nodal stations, and spleen on FDG PET-CT.

Purpose\ud\udEarly and accurate localization of lesions in patients with biochemical recurrence (BCR) of prostate cancer may guide salvage therapy decisions. The present study, 18F-Fluciclovine PET/CT in biochemicAL reCurrence Of Prostate caNcer (FALCON; NCT02578940), aimed to evaluate the effect of 18F-fluciclovine on management of men with BCR of prostate cancer.\udMethods and Materials\ud\udMen with a first episode of BCR after curative-intent primary therapy were enrolled at 6 UK sites. Patients underwent 18F-fluciclovine positron emission tomography/computed tomography (PET/CT) according to standardized procedures. Clinicians documented management plans before and after scanning, recording changes to treatment modality as major and changes within a modality as other. The primary outcome measure was record of a revised management plan postscan. Secondary endpoints were evaluation of optimal prostate specific antigen (PSA) threshold for detection, salvage treatment outcome assessment based on 18F-fluciclovine-involvement, and safety.\udResults\ud\ud18F-Fluciclovine was well tolerated in the 104 scanned patients (median PSA = 0.79 ng/mL). Lesions were detected in 58 out of 104 (56%) patients. Detection was broadly proportional to PSA level; ≤1 ng/mL, 1 out of 3 of scans were positive, and 93% scans were positive at PSA >2.0 ng/mL. Sixty-six (64%) patients had a postscan management change (80% after a positive result). Major changes (43 out of 66; 65%) were salvage or systemic therapy to watchful waiting (16 out of 66; 24%); salvage therapy to systemic therapy (16 out of 66; 24%); and alternative changes to treatment modality (11 out of 66, 17%). The remaining 23 out of 66 (35%) management changes were modifications of the prescan plan: most (22 out of 66; 33%) were adjustments to planned brachytherapy/radiation therapy to include a 18F-fluciclovine-guided boost. Where 18F-fluciclovine guided salvage therapy, the PSA response rate was higher than when 18F-fluciclovine was not involved (15 out of 17 [88%] vs 28 out of 39 [72%]).\udConclusions\ud\ud18F-Fluciclovine PET/CT located recurrence in the majority of men with BCR, frequently resulting in major management plan changes. Incorporating 18F-fluciclovine PET/CT into treatment planning may optimize targeting of recurrence sites and avoid futile salvage therapy.

3069 Background: Over-expression the human epidermal growth factor receptor-2 (HER2) is seen in 20% of breast cancers; this is an adverse prognostic factor and used to guide therapy selection. At present HER2 expression can only be determined using biopsy material using immunohistochemistry or fluorescence in situ hybridisation. Heterogeneous expression of HER2 is now being recognised as a cause of treatment resistance but is difficult to characterise. A non-invasive method for determining HER2 expression could have several advantages and help select appropriate therapy for patients. GE-226 is a novel radiolabelled GE-Affibody radioligand which binds to the HER2 receptor with high affinity at a different epitope than trastuzumab. Methods: Patients with locally advanced or metastatic breast cancer were recruited and scanned for 65 mins after iv injection of 200MBq of GE-226 (mean activity injected for each patient 202MBq (range 164-223MBq, mean radiochemical purity 94%) of radioligand, over one bed position for dynamic imaging, followed by a half-body scan. Blood sampling was used to measure metabolism of the tracer. Safety was assessed. HER2-extracellular domain (ECD) domain was measured in blood. Tumoural uptake was quantified by semi-quantitative and fquantitative parameters in HER2 positive and HER2 negative tumours. Patients had routine baseline FDG imaging. Results: Twenty patients completed the study. GE-226 scans were well tolerated. There were no serious adverse events. GE-226 was slowly metabolised into a single metabolite in the liver; 97% of parent remained at 60 minutes post injection (range 82-100). There was a significant difference in tumoural radioligand uptake between biopsy proven HER2 positive and HER2 negative tumoural patients as measured by SUVmean and SUVmax (p < 0.001). Comparing HER2 positive to HER2 negative cases, there was also a significant difference between tumour to normal tissue uptake ratios SUVmean. Heterogeneous uptake was observed in three patients, two with interlesional uptake variation and one with intralesional heterogeneity. Tumoural uptake increased over time. Normal physiological uptake in salivary glands and the thyroid gland was noted. GE-226 was able to differentiate between lymphadenopathy due to sarcoidosis and cancer in one patient and was superior to FDG which had shown widespread uptake in the benign and malignant nodes. Conclusions: [18F]GE-226 imaging is well tolerated and shows promise for imaging of HER2 positive breast cancer. Further studies with this agent are now planned. Clinical trial information: NCT03827317.

Early and accurate localization of lesions in patients with biochemical recurrence (BCR) of prostate cancer may guide salvage therapy decisions. The present study,Men with a first episode of BCR after curative-intent primary therapy were enrolled at 6 UK sites. Patients underwent

The aim of this study was to evaluate the role of image heterogeneity analysis of standard care magnetic resonance imaging (MRI) in patients with anal squamous cell carcinoma (ASCC) to predict chemoradiotherapy (CRT) outcome. The ability to predict disease recurrence following CRT has the potential to inform personalized radiotherapy approaches currently being explored in novel clinical trials.An IRB waiver was obtained for retrospective analysis of standard care MRIs from ASCC patients presenting between 2010 and 2014. Whole tumor 3D volume-of-interest (VOI) was outlined on T2-weighted (T2w) and diffusion weighted imaging (DWI) of the pre- and post-treatment scans. Independent imaging features most predictive of disease recurrence were added to the baseline clinico-pathological model and the predictive value of respective extended models was calculated using net reclassification improvement (NRI) algorithm. Cross-validation analysis was carried out to determine percentage error reduction with inclusion of imaging features to the baseline model for both endpoints.Forty patients who underwent 1.5 T pelvic MRI at baseline and following completion of CRT were included. A combination of two baseline MR heterogeneity features (baseline T2w energy and DWI coefficient of variation) was most predictive of disease recurrence resulting in significant NRI (p = 0 0.001). This was confirmed in cross-validation analysis with 34.8% percentage error reduction for the primary endpoint and 18.1% reduction for the secondary endpoint with addition of imaging variables to baseline model.MRI heterogeneity analysis offers complementary information, in addition to clinical staging, in predicting outcome of CRT in anal SCC, warranting validation in larger datasets.

In early-stage breast cancer, the primary treatment option for most women is breast-conserving surgery (BCS). There is a clear need for more accurate techniques to assess resection margins intraoperatively, because on average 20% of patients require further surgery to achieve clear margins. Cerenkov luminescence imaging (CLI) combines optical and molecular imaging by detecting light emitted by

We propose the use of computerized process tracing (CPT) tools as an appropriate approach for monitoring the information acquisition and evaluation phase of specific decision processes. CPT tools are unobtrusive and seem particularly relevant for evaluating certain decision tasks that may be supported by decision support systems (DSS). CPT tools can be an important component of DSS development. An information systems research taxonomy developed by previous researchers [29] [36] is used to position research work involving the methodology of CPT. Using a critique suggested by Libby [28], CPT tools are evaluated and compared to alternative process tracing tools. A brief empirical example using CPT is provided, and future uses relative to DSS are suggested. The appendix includes an example of a specific CPT tool.

Understanding how people search through and combine information before making decisions is an important concern in the study of decision making and in the design of decision support systems (DSS). The purpose of this study is to examine DSS search strategies in relation to the body of empirical research on information load. Prior research is examined in relation to basic empirically-testable hypotheses and compared to the results of this study as a way of validating the procedures used here. The transfer of information load empirical research to a DSS scenario is confirmed statistically. Then, results of an analysis of information search patterns under DSS conditions are described. Finally, implications for DSS design are discussed in terms of possible search support mechanisms for specific search strategies.

We report on a two-part longitudinal study of computer-supported cooperative work. It focuses on the impact of coordinating and enabling technologies through an examination of computer-supported information exchange patterns. Colleagues were required to work together to complete a project within a specified time frame. The patterns of information exchange observed in this environment provide evidence as to which aspects of groupware are perceived as helpful by users, and provide an impetus for further research.The objectives of this research are to: 1) examine patterns of information exchange in order to provide descriptive data on the process of using groupware; and 2) identify factors that need to be considered for effective and efficient use of groupware in a CSCW environment. The two studies allow for an investigation of the difference between 1) small novice-user groups formed across class sections (locations) with each group responsible for developing a complete proposal and 2) a large experienced-user group formally divided into subgroups, with each subgroup responsible for developing a portion of a proposal.In the first study, participants were graduate students in an advanced information systems course. The research task was to develop a proposal for a company with inventory data control and other related problems (inefficient production layouts and machine utilization) in a simulated business information systems consulting environment. There were six teams with four or five participants on each team. Each team was split across two sections of the course. Differential information was provided to each section and team members were encouraged to use the groupware for communications concerning the project. The participants were novice users of the software.In the second study, participants were graduate students in a data communications and networking course. All nine had taken the previous course and were experienced with the groupware. The research task was a team network analysis and design project. Participants were encouraged to use the groupware for communications as in Study 1. They were divided into three teams of three, with one team responsible for the LAN portion of the proposal, the second team responsible for the WAN portion, and the third team responsible for the integration of the LAN and WAN material, and for the development of the proposal package. A graduate student who had previously taken the course acted as project manager.After participants had completed the two projects, the messages were categorized using a previously developed coding scheme. The message frequency and type yielded descriptive information regarding the impact of the technology on interactions among participants, and the relationship between decision outcomes and patterns of information exchange.The findings include: 1) the groupware used needs to be matched to the task, group structure, and environment; 2) minimal social use of the system occurred over time; 3) the message mix tended to shift from scheduling and coordinating efforts to task-related efforts as deadlines loomed; and 4) the system provided descriptive information on team work habits. These patterns and other qualitative data gathered from participants provide insight into the use of the groupware, group behavior, and the importance of group structure, task, and environment.

Software for supporting cooperative work, or groupware, is an approach for increasing project team productivity by changing the way team members work and communicate with each other. Since groupware use can be influenced by various individual, team, and organizational factors, empirical research is needed to "... study the flow of members' interaction to discover the impact the technology is having on the nature of the group's cognitions, actions, and feelings, and the relationship between these attributes of information exchange and decision outcomes (DeSanctis and Gallupe, 1987, p. 603)." The objective of this study is to examine patterns of computer-supported information exchange in a cooperative work environment. The environment requires colleagues to work together to complete a project within a specified time frame. The patterns of information exchange observed should provide insight into what aspects of groupware are perceived as helpful by users, and provide directions for further research.

The application of operational analog computers to simulate the dynamic behavior of an antenna is dis cussed. The structural model used is developed from modal as well as nodal equations. The model repre senting motor and control systems is derived from typical drive and control-system equations. The simulation is deliberately more detailed than neces sary in order to establish the effects of parameters that usually are neglected as higher-order effects. The validity of the simulation is achieved by com paring computer results with experimental results. The difficulties encountered in calculating adequate input data and correlating analytical and experimental results are noted.

Understanding how people search and combine information to make decisions is an important concern in the study of decision making because people tend to search information consistent with the decision process employed. Thus, analysis of these search strategies provides insight into the decision process, and into the design of computerbased aids for decision making.