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Applying Machine Learning and Bayesian Inference to Identify and Locate Moving Anthropogenic Sources Using Distributed Acoustic Sensing Data

Distributed acoustic sensing (DAS) systems, which use existing telecommunication fibers, offer high‐resolution capabilities ideal for recording anthropogenic sources. However, the complexity of urban environments and the large amount of data recorded by DAS require automated methods to efficiently detect and categorize anthropogenic sources. Here, we evaluate how well three machine learning models (k‐nearest neighbor [k‐NN], convolutional neural networks, and recurrent‐convolutional neural networks) can identify various anthropogenic sources recorded by DAS. Our findings reveal that both k‐NN and neural network methods perform well in high signal‐to‐noise ratio (SNR) settings. However, their accuracy decreases at SNRs <4. We also use Kalman filtering, a form of Bayesian inference, on backprojected locations of these sources to recover locations that generally fall within standard smartphone Global Positioning System errors. By combining machine learning and Kalman filter results, we calculate a multidimensional model of moving anthropogenic sources. These results demonstrate the potential of DAS data in urban seismology for accurately identifying and locating such sources. Depending on the research objectives, these sources can be further studied or filtered out to improve the quality of seismic data for earthquake studies. Such methods provide a valuable tool for urban seismology and seismic hazard analysis.

Luckie, Thomas William [Sandia National Laboratori↗

A Risk Analysis Tool for Estimating the Risk of Electrical Failures Due to Human Induced Defects

Aerospace electrical systems are required to withstand and adequately operate in extremely harsh environments that include, for example, high radiation exposure, temperature extremes, intense vibrational stress and drastic temperature cycling. The nature of aerospace electronics also demands high reliability since, with very few exceptions, there is no chance for hardware servicing or repairs. Common risk mitigation techniques for this type of situation are to perform a Reliability Analysis of the system throughout the development cycle, and to use electrical components that are regarded as “high reliability” because of additional controls and requirements applied in their design, manufacturing and testing. Unfortunately, studies have shown that even though these techniques are used, many systems fail to meet mission requirements well before the predicted lifetimes. This paper presents the analysis of failures of electrical parts, experienced during various stages of system development, at NASA Goddard Space Flight Center, Greenbelt MD, between the years 2001 and 2013. These components were subjected to qualification, screening and testing in which the goal was to ensure that the components would survive the stresses of the mission. The analysis categorizes failures by part type and failure mechanisms. One of the results of the analysis was the realization that a surprising proportion of failures experienced during system integration and testing were caused by human error (i.e. human induced defect). Further analysis included the determination of root failure mechanisms and any influencing factors contributing to these failures. The major causes of these defects were attributed to electrostatic damage (ESD), electrical overstress (EOS), mechanical overstress (MOS), and thermal overstress (TOS). Finally, the study proposes a risk analysis tool which incorporates these major causes for the failures, termed error-producing conditions (EPCs), and a proportionality factor representing the number of each type of failure that has occurred at the facility under study. These factors are quantified and used to communicate the risk of human induced defects for the assembly, integration and testing of space hardware based on the system’s electrical parts list. The new risk identification can trigger risk-mitigating actions more effectively, based on the presence of component categories or other hazardous conditions that have a history of failure due to human error.

Majewicz, Peter J.↗

Assessing the Viability of Using GEOS-Forecast Product for Landslides Forecasting: A Step Toward Early Warning System

Landslides across the globe are mostly triggered by extreme rainfall events affecting infrastructure, transportation and livelihoods. The risks are rarely quantified due to lack of data, analytical skills and limited modeling techniques. Knowledge of local to global scale landslide risks provides communities and national agencies the ability to adapt disaster management practices to mitigate and recover from these hazards. In order to minimize the risks and improve characterization of community resilience to landslides, it is vital to have reliable information about the factors triggering landslides such as rainfall, well ahead in time. Forecasting potential landslide activity and impacts can be achieved through reliable precipitation forecast models. However, it is challenging because of the temporal and spatial variability of precipitation, an important factor in triggering landslides. Evaluation of the precipitation field, associated errors, and sampling uncertainties is integral for development of efficient and reliable landslide forecasting and early warning system. This study develops a methodology to assess the viability of using a precipitation field provided by a global model and its potential integration in the landslide forecasting system. The study focuses on the comparison between the IMERG (Integrated Multi-satellitE Retrievals for Global Precipitation Mission) and GEOS (NASA Goddard Earth Observing System)-Forecast product over contiguous United States (CONUS). GEOS model assimilates new observations every 6 hours, at 00, 06, 12, and 18 UTC. The framework is tested on the GEOS-Forecast Model initialized at 00 UTC using daily IMERG early product as reference using both categorical and continuous statistics. The categorical statistics includes the probability of detection (POD), success ratio (SR), critical success index (CSI), and the hit bias. Continuous statistics such as correlation, normalized standard deviation, and root-mean-square error are also evaluated. Overall, GEOS-Forecast precipitation field over the analysis period (~1 year) show underestimation with respect to IMERG early for the daily accumulated rainfall. However, the probability distribution function and cumulative distribution function of both show similar patterns. In terms of correlations, POD, SR, CSI, hit bias, the performance varies with respect to the rainfall threshold used.

Sana Khan↗

Estimation of breast percent density in raw and processed full field digital mammography images via adaptive fuzzy c-means clustering and support vector machine segmentation

Purpose: The amount of fibroglandular tissue content in the breast as estimated mammographically, commonly referred to as breast percent density (PD%), is one of the most significant risk factors for developing breast cancer. Approaches to quantify breast density commonly focus on either semiautomated methods or visual assessment, both of which are highly subjective. Furthermore, most studies published to date investigating computer-aided assessment of breast PD% have been performed using digitized screen-film mammograms, while digital mammography is increasingly replacing screen-film mammography in breast cancer screening protocols. Digital mammography imaging generates two types of images for analysis, raw (i.e., 'FOR PROCESSING') and vendor postprocessed (i.e., 'FOR PRESENTATION'), of which postprocessed images are commonly used in clinical practice. Development of an algorithm which effectively estimates breast PD% in both raw and postprocessed digital mammography images would be beneficial in terms of direct clinical application and retrospective analysis. Methods: This work proposes a new algorithm for fully automated quantification of breast PD% based on adaptive multiclass fuzzy c-means (FCM) clustering and support vector machine (SVM) classification, optimized for the imaging characteristics of both raw and processed digital mammography images as well as for individual patient and image characteristics. Our algorithm first delineates the breast region within the mammogram via an automated thresholding scheme to identify background air followed by a straight line Hough transform to extract the pectoral muscle region. The algorithm then applies adaptive FCM clustering based on an optimal number of clusters derived from image properties of the specific mammogram to subdivide the breast into regions of similar gray-level intensity. Finally, a SVM classifier is trained to identify which clusters within the breast tissue are likely fibroglandular, which are then aggregated into a final dense tissue segmentation that is used to compute breast PD%. Our method is validated on a group of 81 women for whom bilateral, mediolateral oblique, raw and processed screening digital mammograms were available, and agreement is assessed with both continuous and categorical density estimates made by a trained breast-imaging radiologist. Results: Strong association between algorithm-estimated and radiologist-provided breast PD% was detected for both raw (r= 0.82, p < 0.001) and processed (r= 0.85, p < 0.001) digital mammograms on a per-breast basis. Stronger agreement was found when overall breast density was assessed on a per-woman basis for both raw (r= 0.85, p < 0.001) and processed (0.89, p < 0.001) mammograms. Strong agreement between categorical density estimates was also seen (weighted Cohen's {kappa}{>=} 0.79). Repeated measures analysis of variance demonstrated no statistically significant differences between the PD% estimates (p > 0.1) due to either presentation of the image (raw vs processed) or method of PD% assessment (radiologist vs algorithm). Conclusions: The proposed fully automated algorithm was successful in estimating breast percent density from both raw and processed digital mammographic images. Accurate assessment of a woman's breast density is critical in order for the estimate to be incorporated into risk assessment models. These results show promise for the clinical application of the algorithm in quantifying breast density in a repeatable manner, both at time of imaging as well as in retrospective studies.

60 APPLIED LIFE SCIENCES↗

Impact of Neoadjuvant Prostate-Specific Antigen Kinetics on Biochemical Failure and Prostate Cancer Mortality: Results From a Prospective Patient Database

Purpose: To confirm findings from an earlier report showing that neoadjuvant (NA) prostate-specific antigen (PSA) halving time (PSAHT) impacts biochemical failure (BF) rates, and to examine its association with prostate cancer-specific survival (PCSS), in a large prospective cohort of patients. Methods and Materials: A total of 502 patients were selected from a prospective database, who had localized prostate adenocarcinoma treated with 2-12 months of neoadjuvant androgen deprivation therapy (N-ADT) followed by external beam radiation therapy (EBRT) between 1994 and 2000, and had at least 2 NA PSA values. Seventy-four percent of patients had high-risk prostate cancer. Median initial PSA value, N-ADT duration, total ADT duration, and radiation therapy dose were 14 ng/mL, 6.9 months, 10.8 months, and 68 Gy, respectively. Results: At a median follow-up of 9.9 years, 210 patients have had a BF. Median PSAHT was 18 days. On univariate analysis, PSAHT was not shown to predict for BF (P=.69) or PCSS (P=.28). However, NA nadir PSA (nanPSA) and post-therapy nadir PSA (ptnPSA), when analyzed as continuous or categoric variables, predicted for BF (P<.001) and PCSS (P<.001). On multivariate analysis, nanPSA (P=.037) and ptnPSA (P<.001) continued to be significantly associated with BF. However, N-ADT duration lost significance (P=.67), and PSAHT remained a nonsignificant predictor (P=.97). For PCSS, multivariate analysis showed nanPSA (P=.049) and ptnPSA (P<.001) to be significant. Again PSAHT (P=.49) remained nonsignificant. Conclusions: In this large, prospective cohort of patients, NA PSA kinetics, expressed as PSAHT, did not predict BF or PCSS. However, nadir PSAs, in both the NA and post-therapy settings, were significant predictors of BF and PCSS. Optimization of therapy could potentially be based on early PSA response, with shorter durations of ADT for those predicted to do favorably, and intensification of therapy for those likely to have poorer outcomes.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Using A Guided Interview to Create an Individual Exposure Profile for The Lifetime Surveillance of Astronaut Health (LSAH)

BACKGROUND To support NASA’s Lifetime Surveillance of Astronaut Health (LSAH) project, Individual Exposure Profiles (IEPs) were developed to record an astronaut’s pre-, in-, and post-NASA exposures. NASA astronauts were invited to participate in a one-time guided interview to review known hazard exposures and medical history documented in NASA records and to add new information not otherwise reported. The purpose of the IEP project was to determine if any significant information was gained from these interviews and identify potential trends in long-term health. METHODOLOGY The pre-filled exposure profile data was extracted from several sources including medical records, biographies, and LSAH records. The information that was pre-filled before the interview included occupational exposures prior to selection to the Astronaut Corps, during active astronaut career (e.g., EVA and ground-based training, on-orbit exposures), and after active career. The IEPs also contained relevant medical history (e.g., audiometry, illnesses, injuries) and significant non-occupational exposures. 189 interviews were conducted from 2012-2014. A Microsoft Access database was created to store the information collected in the IEPs before and after the interviews. The database houses the information from the IEPs to track the updates made to the original data. By analyzing which astronauts supplied additional information and which kinds of data were consistently added, potential gaps and trends in missing data may be identified. In designing the database, an efficient structure was implemented for ease of inputting data and to create variables that would generate quantifiable data. Creating standardized variables within the structure helped ease the process of inputting, organizing data, and analyzing data. Additional updates/data were denoted and were categorized by type of update. The categories identified were “Confirmed”, “Confirmed & Supplemented”, “Supplemented”, “Denied”, “Denied & Supplemented”, and “Other”. STATISTICAL ANALYSIS AND RESULTS To assess frequency of exposure updates, descriptive statistics will be generated and stratified by relevant factors such as astronaut selection decade, age at selection, and program/era. Hypothesis testing will be performed to understand the associations between updates to exposure information and population characteristics.

Astronaut health↗

The Relationship Between Local Recurrence and Radiotherapy Treatment Volume for Soft Tissue Sarcomas Treated With External Beam Radiotherapy and Function Preservation Surgery

Purpose: To examine the geometric relationship between local recurrence (LR) and external beam radiotherapy (RT) volumes for soft-tissue sarcoma (STS) patients treated with function-preserving surgery and RT. Methods and Materials: Sixty of 768 (7.8%) STS patients treated with combined therapy within our institution from 1990 through 2006 developed an LR. Thirty-two received preoperative RT, 16 postoperative RT, and 12 preoperative RT plus a postoperative boost. Treatment records, RT simulation images, and diagnostic MRI/CT data sets of the original and LR disease were retrospectively compared. For LR location analysis, three RT target volumes were defined according to the International Commission on Radiation Units and Measurements 29 as follows: (1) the gross tumor or operative bed; (2) the treatment volume (TV) extending 5 cm longitudinally beyond the tumor or operative bed unless protected by intact barriers to spread and at least 1-2 cm axially (the TV was enclosed by the isodose curve representing the prescribed target absorbed dose [TAD] and accounted for target/patient setup uncertainty and beam characteristics), and (3) the irradiated volume (IRV) that received at least 50% of the TAD, including the TV. LRs were categorized as developing in field within the TV, marginal (on the edge of the IRV), and out of field (occurring outside of the IRV). Results: Forty-nine tumors relapsed in field (6.4% overall). Nine were out of field (1.1% overall), and 2 were marginal (0.3% overall). Conclusions: The majority of STS tumors recur in field, indicating that the incidence of LR may be affected more by differences in biologic and molecular characteristics rather than aberrations in RT dose or target volume coverage. In contrast, only two patients relapsed at the IRV boundary, suggesting that the risk of a marginal relapse is low when the TV is appropriately defined. These data support the accurate delivery of optimal RT volumes in the most precise way using advanced technology and image guidance.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Emerging Per- and Polyfluoroalkyl Substances in Tap Water from the American Healthy Homes Survey II

Humans experience widespread exposure to anthropogenic per- and polyfluoroalkyl substances (PFAS) through various media, which can lead to a wide range of negative health impacts. Tap water is an important source of exposure in communities with any degree of contamination but routine or large-scale PFAS monitoring often depends on targeted analytical methods limited to measuring specific PFAS. We analyzed 680 tap water samples from the American Healthy Homes Survey II for PFAS using non-targeted analysis (NTA) to expand the range of detectable PFAS. Based on detection frequency and relative abundance, about half of the identified PFAS were found only by NTA. We identified (with varying degrees of confidence) 75 distinct PFAS, including 57 exclusively detected by NTA. The identified PFAS are members of seven structural subclasses differentiated by their head groups and degree of fluorination. Clustering analysis categorized the PFAS into four coabundance groups dominated by specific PFAS subclasses. One group uniquely identified by NTA contains zwitterionic PFAS and other PFAS transformation products which are likely associated with aqueous firefighting foam contaminants in a small number of spatially correlated samples. These results help further characterize the scope of exposure to emerging PFAS experienced by the U.S. population via tap water and augment nationwide targeted-PFAS monitoring programs.

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTAN↗

Aging Hanford Nuclear Waste Using Carbon Dioxide to Evaluate Corrosion at Lower pH Limits - 18467

Samples of Hanford Nuclear Reservation (HNR) tank waste and simulated Hanford tank waste were exposed to carbon dioxide gas (CO{sub 2}) in the laboratory in order to decrease the pH of the solution. Sodium hydroxide is required to be added to some tanks according to waste handling specifications to keep tanks protected from pitting corrosion, but the maximum-allowed volume in some tanks is currently approaching capacity. Decreasing the pH of tank solutions using CO{sub 2} gas mimics the environmental exposure chemistry, does not add sodium, and allows for testing on solutions currently categorized as out-of-specification according to technical waste handling documents. Legacy alloy A537 Class 1 carbon steel was used to construct the AN tanks on the HNR and was utilized for this testing. The planned testing of three solutions included a simulant for feasibility and a waste solution from Tank 241-AN-102 (AN-102), taken in 2013, which was run in duplicate. The solutions were evaluated for corrosion potential using cyclic potentiodynamic polarization (CPP) scans to determine the propensity for stress corrosion cracking and pitting corrosion. Results in all solutions showed that pitting potential was low when the pH was above 11 and temperatures were below 40 deg. C. As solution pHs dipped into the 10- 10.5 range, there were mixed results. CPP scans were initially run at the higher temperature of 50 deg. C, accelerating corrosion rates. Solution pHs that did not indicate corrosion were further exposed to CO{sub 2}. Solutions with mixed or positive pitting results were rerun at 40 deg. C. The first failed run on the tank solution was seen when testing the duplicate sample at 50 deg. C and a pH of 13.01. When this solution was retested at 40 deg. C, the CPP scan did not show corrosion. A mixed corrosion result was obtained from a scan run at the final pH of 10 when tested at 50 deg. C. Upon completion of testing a visual inspection of the coupon did not show corrosion products on its surface. These results provide assurance that tanks containing slightly reduced pHs are still protected from pitting corrosion. Tank integrity assurance at a lower pH limit in Tank AN-102 could slow sodium addition and the rising volume of hazardous waste. Other benefits of reducing the pH specification would be reduced costs associated with retrieving and storing smaller volumes of hazardous waste, a reduced number of radiation exposure events (required for pH modification of tank waste), and a potential for a decreased volume required to be immobilized for long-term storage in a vitrified (glass) phase. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

SU-F-I-77: Radiation Dose in Cardiac Catheterization Procedures: Impact of a Systematic Reduction in Pulsed Fluoroscopy Frame Rate

Purpose: To evaluate whether one small systematic reduction in fluoroscopy frame rate has a significant effect on the total air kerma and/or dose area product for diagnostic and interventional cardiac catheterization procedures. Methods: The default fluoroscopy frame rate (FFR) was lowered from 15 to 10 fps in 5 Siemens™ Axiom Artis cardiac catheterization labs (CCL) on July 1, 2013. A total of 7212 consecutive diagnostic and interventional CCL procedures were divided into two study groups: 3602 procedures from 10/1/12 –6/30/13 with FFR of 15 fps; and 3610 procedures 7/1/13 – 3/31/14 at 10 fps. For each procedure, total air kerma (TAK), fluoroscopy skin dose (FSD), total/fluoroscopy dose area products (TAD, FAD), and total fluoroscopy time (FT) were recorded. Patient specific data collected for each procedure included: BSA, sex, height, weight, interventional versus diagnostic; and elective versus emergent. Results: For pre to post change in FFR, each categorical variable was compared using Pearson’s Chi-square test, Odds ratios and 95% confidence intervals. No statistically significant difference in BSA, height, weight, number of interventional versus diagnostic, elective versus emergent procedures was found between the two study groups. Decreasing the default FFR from 15 fps to 10 fps in the two study groups significantly reduced TAK from 1305 to 1061 mGy (p<0.0001), FSD from 627 to 454 mGy (p<0.0001), TAD from 8681 to 6991 uGy × m{sup 2}(p<0.0001), and FAD from 4493 to 3297 uGy × m{sup 2}(p<0.0001). No statistically significant difference in FT was noted. Clinical image quality was not analyzed, and reports of noticeable effects were minimal. From July 1, 2013 to date, the default FFR has remained 10 fps. Conclusion: Reducing the FFR from 15 to 10 fps significantly reduced total air kerma and dose area product which may decrease risk for potential radiation-induced skin injuries and improve patient outcomes.

60 APPLIED LIFE SCIENCES↗

Aspirin and Statin Nonuse Associated With Early Biochemical Failure After Prostate Radiation Therapy

Purpose: To present the largest retrospective series investigating the effect of aspirin and statins, which are hypothesized to have antineoplastic properties, on biochemical failure (nadir plus 2 ng/mL) after prostate radiation therapy (RT). Methods and Materials: Between 1989 and 2006, 2051 men with clinically localized prostate cancer received definitive RT alone (median dose, 76 Gy). The rates of aspirin use and statin use (defined as any use at the time of RT or during follow-up) were 36% and 34%, respectively. The primary endpoint of the study was an interval to biochemical failure (IBF) of less than 18 months, which has been shown to be the single strongest predictor of distant metastasis, prostate cancer survival, and overall survival after RT. Patient demographic characteristics and tumor staging factors were assessed with regard to associations with the endpoint. Univariate analysis was performed with the {chi}{sup 2} test for categorical variables and the Wilcoxon test for continuous variables. Multivariable analysis was performed with a multiple logistic regression. Results: The median follow-up was 75 months. Univariate analysis showed that an IBF of less than 18 months was associated with aspirin nonuse (P<.0001), statin nonuse (P<.0001), anticoagulant nonuse (P=.0006), cardiovascular disease (P=.0008), and prostate-specific antigen (continuous) (P=.008) but not with Gleason score, age, RT dose, or T stage. On multivariate analysis, only aspirin nonuse (P=.0012; odds ratio, 2.052 [95% confidence interval, 1.328-3.172]) and statin nonuse (P=.0002; odds ratio, 2.465 [95% confidence interval, 1.529-3.974]) were associated with an IBF of less than 18 months. Conclusions: In patients who received RT for prostate cancer, aspirin or statin nonuse was associated with early biochemical failure, a harbinger of distant metastasis and death. Further study is needed to confirm these findings and to determine the optimal dosing and schedule, as well as the relative benefits and risks, of both therapies in combination with RT.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

An Approach for Assessing Consequences of Potential Supply Chain and Insider Contributed Cyber Attacks on Nuclear Power Plants

The Stuxnet attack at the Natanz facility is an example of a targeted and successful cyber attack on a nuclear facility. Snowden's release of National Security Agency documents demonstrated the consequences of the insider threat. More recently, the United States tried to attack North Korea but failed, South Korea was attempting to attack North Korea, and both applied Stuxnet-like approaches. These sophisticated targeted attacks differ from web-site hacking events that are reported almost daily in the news mainly because targeted attacks require detailed design and operation information of the systems attacked and/or are often carried out by insiders. For instance, in order to minimize disruption of facilities around the world, Stuxnet remained idle until it recognized the specific configuration of the Natanz facility, demonstrating that the attackers possessed extremely detailed information about the facility. Such targeted cyber attacks could become a national-level military weapon and be used in coercion of hostile countries. While U.S. nuclear power plants (NPPs) are well designed and protected and not easily attacked through internet hacking, there have been a few digital-system-related incidents. For example, in 2003, the Slammer worm breached the private network of the Davis Besse plant and disabled a safety monitoring system for almost five hours. The breach did not pose a safety hazard because the plant was offline, but it demonstrates the vulnerability of NPP systems. The worm did not enter the plant systems directly; it began by entering the systems of a Davis Besse contractor, and entered through the T1 line bridging the contractor's computer and Davis Besse's corporate networks. The T1 line was not protected by the plant's firewall. The success of the Stuxnet-Natanz case demonstrates that supply-chain level attack (i.e., physically tampering with digital systems to install undetectable malware for the purpose of bringing harm to a player further down the supply chain network) plays a crucial role in a successful attack. Although attacking an NPP naturally requires more complex strategies and tactics than internet hacking, NPP's have a variety of sophisticated and possibly sensitive systems that may be attacked. Previous studies, for example, Baylon, have identified and confirmed that such attack strategies and tactics can be designed and could produce severe damage to an NPP. Current NPPs were designed according to design basis accidents that predate use of the internet by the general public and did not take into consideration potential cyber attacks that could be carried out by state-sponsored attackers and malicious insiders. To date, no detailed engineering analysis has been performed to realistically examine the consequences these attacks may have on the plants. In this paper, we discuss an approach for assessing the potential consequences of Stuxnet type of attacks. We will examine the engineering criteria used in designing the plants, develop possible attack scenarios in terms of the structures, components, and systems (SSCs) being controlled by digital systems at the NPPs, perform engineering analysis to determine if the attacks would impose conditions that are beyond design bases, and categorize the consequences of the potential accidents. (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

Waste Management Strategy for Dismantling Waste to Reduce Costs for Power Plant Decommissioning - 13543

Decommissioning of nuclear power plants generates large volumes of radioactive or potentially radioactive waste. The proper management of the dismantling waste plays an important role for the time needed for the dismantling phase and thus is critical to the decommissioning cost. An efficient and thorough process for inventorying, characterization and categorization of the waste provides a sound basis for the planning process. As part of comprehensive decommissioning studies for Nordic NPPs, Westinghouse has developed the decommissioning inventories that have been used for estimations of the duration of specific work packages and the corresponding costs. As part of creating the design basis for a national repository for decommissioning waste, the total production of different categories of waste packages has also been predicted. Studsvik has developed a risk based concept for categorization and handling of the generated waste using six different categories with a span from extremely small risk for radiological contamination to high level waste. The two companies have recently joined their skills in the area of decommissioning on selected market in a consortium named 'ndcon' to further strengthen the proposed process. Depending on the risk for radiological contamination or the radiological properties and other properties of importance for waste management, treatment routes are proposed with well-defined and proven methods for on-site or off-site treatment, activity determination and conditioning. The system is based on a graded approach philosophy aiming for high confidence and sustainability, aiming for re-use and recycling where found applicable. The objective is to establish a process where all dismantled material has a pre-determined treatment route. These routes should through measurements, categorization, treatment, conditioning, intermediate storage and final disposal be designed to provide a steady, un-disturbed flow of material to avoid interruptions. Bottle-necks in the process causes increased space requirements and will have negative impact on the project schedule, which increases not only the cost but also the dose exposure to personnel. For these reasons it is critical to create a process that transfers material into conditioned waste ready for disposal as quickly as possible. To a certain extent the decommissioning program should be led by the waste management process. With the objective to reduce time for handling of dismantled material at site and to efficiently and environmental-friendly use waste management methods (clearance for re-use followed by clearance for recycling), the costs for the plant decommissioning could be reduced as well as time needed for performing the decommissioning project. Also, risks for delays would be reduced with a well-defined handling scheme which limits surprises. Delays are a major cost driver for decommissioning projects. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Ecological risk assessment of elemental pollution in sediment from Tunku Abdul Rahman National Park, Sabah

Eleven (11) surface sediment samples were collected from Tunku Abdul Rahman National Park, Sabah. The neutron activation analysis (NAA) and inductively coupled plasma-mass spectrometry (ICP-MS) techniques were applied for the determinations metal contents and their distributions in sediment samples. The results shown that Arsenic (As) concentrations are enriched at all sampling stations except for station TAR 09, with enrichment factor (EF) values ranged from 1.1 to 7.2. The elements such as Cd, Cr, Sb and U showed enrichment at a few stations and other elements (Cr, Cu, Pb, Th, Zn) shown as background levels in all stations. Degrees of contamination in this study were calculated base on concentrations of six elements (As, Cd, Cr, Cu, Pb, and Zn). TAR 11 station can be categorized as very high degree of contamination with degree of contamination value of 43.2. TAR 07 station can be categorized as a considerable degree of contamination (contamination value of 16.9). Six stations (TAR 01, 03, 04, 05, 06, 08, 10) showed moderate degree of contamination, with contamination values ranging from 8.0 to 16.0. TAR 02 and TAR 09 stations showed low degree of contaminations (< 8.0). TAR 11 showed very high ecological risk index (R{sub I}) with RI value is 916. TAR 07 and TAR 10 showed moderate ecological risk index with R{sub I} value 263 and 213, respectively. Other stations showed low ecological risk with RI values ranging from 42.3 to 117 (< 150). Very high ecological risk index could give an adverse effect to the benthic organism. The data obtained from the enrichment factor, degree of contamination and ecological risk index provided vital information, which can be used for future comparison. Information from the present study will be useful to the relevant government agencies and authorities in preparing preventive action to control direct discharge of heavy metals from industries, agro-base activities and domestic waste to the rivers and the sea.

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTAN↗

DMARD use is associated with a higher risk of dementia in patients with rheumatoid arthritis: A propensity score-matched case–control study

Background: Patients with rheumatoid arthritis (RA) exhibit an increased risk of dementia. Disease-modifying antirheumatic drugs (DMARDs) are commonly used to slow RA progression, but studies investigating the relationship between DMARDs and dementia in patients with RA are lacking. We investigated the relationship between DMARDs and dementia in patients with RA. Methods: Using the National Health Insurance Research Database, patients aged ≥ 20 years, who were newly diagnosed with RA between 2000 and 2011 were identified. Patients with RA who had dementia comprised the dementia group, and patients with RA who did not have dementia comprised the control group. The groups were matched at a 1:1 ratio by the propensity score. DMARDs were categorized into conventional synthetic DMARDs (csDMARDs) and biological DMARDs (bDMARDs). Logistic regression models were used to calculate the odds ratio and 95% confidence interval (CI) to evaluate the association between DMARD use and the risk of dementia in patients with RA. Results: A total of 957 patients with RA and dementia, and 957 patients with RA but not dementia, were enrolled. The risk of dementia was determined to be 1.63-fold higher in patients with RA with csDMARD use than in those without csDMARD use (95% CI = 1.33–2.00). No significant risk of dementia was observed in patients with RA who used bDMARDs compared with their counterparts. However, patients with RA who used hydroxychloroquine, methotrexate, and sulfasalazine exhibited significant risks of dementia, irrespective of cumulative exposure days. Conclusion: Patients with RA who used csDMARDs exhibit significant association with dementia. - Highlights: • Patients with RA who used csDMARDs exhibited a 1.63-fold higher risk of dementia than did those who did not use csDMARDs. • No significant risk of dementia was observed in patients with RA who used bDMARDs. • The use of csDMARDs was significantly associated with vascular dementia (OR = 1.78, 95% CI = 1.21–2.61).

60 APPLIED LIFE SCIENCES↗

Peripherally Inserted Central Catheter-Related Infections in a Cohort of Hospitalized Adult Patients

PurposeTo determine the incidence and the risks factors of peripherally inserted central catheter (PICC)-related infectious complications.Materials and MethodsMedical charts of every in-patient that underwent a PICC insertion in our hospital between January 2010 and October 2013 were reviewed. All PICC-related infections were recorded and categorized as catheter-related bloodstream infections (CR-BSI), exit-site infections, and septic thrombophlebitis.ResultsNine hundred and twenty-three PICCs were placed in 644 unique patients, mostly male (68.3 %) with a median age of 58 years. 31 (3.4 %) PICC-related infections occurred during the study period corresponding to an infection rate of 1.64 per 1000 catheter-days. We observed 27 (87.1 %) CR-BSI, corresponding to a rate of 1.43 per 1000 catheter-days, 3 (9.7 %) septic thrombophlebitis, and 1 (3.2 %) exit-site infection. Multivariate logistic regression analysis showed a higher PICC-related infection rate with chemotherapy (odds ratio (OR) 7.2–confidence interval (CI) 95 % [1.77–29.5]), auto/allograft (OR 5.9–CI 95 % [1.2–29.2]), and anti-coagulant therapy (OR 2.2–95 % [1.4–12]).ConclusionChemotherapy, auto/allograft, and anti-coagulant therapy are associated with an increased risk of developing PICC-related infections.Clinical AdvanceChemotherapy, auto/allograft, and anti-coagulant therapy are important predictors of PICC-associated infections. A careful assessment of these risk factors may be important for future success in preventing PICC-related infections.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

One Decade Later: Trends and Disparities in the Application of Post-Mastectomy Radiotherapy Since the Release of the American Society of Clinical Oncology Clinical Practice Guidelines

Purpose: In 2001 ASCO published practice guidelines for post mastectomy radiotherapy (PMRT). We analyzed factors that influence the receipt of radiotherapy therapy and trends over time. Methods and Materials: We analyzed 8889 women who underwent mastectomy as primary surgical treatment for stage II or III breast cancer between 1995 and 2008 using data from the Kentucky Cancer Registry. We categorized patients according to ASCO group: group 1, PMRT not routinely recommended (T2, N0); group 2, PMRT controversial/evidence insufficient (T1-2, N1); group 3, PMRT recommended or suggested (T3-4 or N2-3). Probability of receiving PMRT was assessed using logistic regression. Results: Overall, 24.0% of women received PMRT over the study period. The rates of PMRT for group 1, 2, and 3 were 7.5%, 19.5%, and 47.3%, respectively. Since 2001, there was an increase in the use of PMRT (from 21.1%-26.5%, P<.0001), which occurred mainly among group 3 members (from 40.8%-51.2%, P<.0001). The average rate remained constant in group 1 (from 7.1%-7.4%, P=.266) and decreased in group 2 (from 20.0%-18.1%, P<.0001). On multivariate analysis, the rate of PMRT was significantly lower for women aged >70 years (vs. younger), rural Appalachia (vs. non-Appalachia) populations, and Medicaid (vs. privately insured) patients. Conclusions: ASCO guidelines have influenced practice in an underserved state; however PMRT remains underused, even for highest-risk patients. Barriers exist for elderly, rural and poor patients, which independently predict for lack of adequate care. Updated guidelines are needed to clarify the use of PMRT for patients with T1-2, N1 disease.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Air pollution and emergency department visits for respiratory diseases: A multi-city case crossover study

Highlights: • Extensive research exists on the effects of ambient air pollution on respiratory diseases. • Emergency department visits for respiratory diseases increase after days with higher concentrations of air pollution. • Ambient pollution, even at low concentrations, appear to adversely affect the respiratory system. Increasing evidence suggests that ambient air pollution is a major risk factor for both acute and chronic respiratory disease exacerbations and emergencies. The objective of this study was to determine the association between ambient air pollutants and emergency department (ED) visits for respiratory conditions in nine districts across the province of Ontario in Canada. Health, air pollutant (PM{sub 2.5}, NO{sub 2}, O{sub 3}, and SO{sub 2}), and meteorological data were retrieved from April 2004 to December 2011. Respiratory diseases were categorized as: chronic obstructive pulmonary disease (COPD, including bronchiectasis) and acute upper respiratory diseases. A case-crossover design was used to test the associations between ED visits and ambient air pollutants, stratified by sex and season. For COPD among males, positive results were observed for NO{sub 2} with lags of 3–6 days, for PM{sub 2.5} with lags 1–8, and for SO{sub 2} with lags of 4–8 days. For COPD among females, positive results were observed for O{sub 3} with lags 2–4 days, and for SO{sub 2} among lags of 3–6 days. For upper respiratory disease emergencies among males, positive results were observed for NO{sub 2} (lags 5–8 days), for O{sub 3}, (lags 0–6 days), PM{sub 2.5} (all lags), and SO{sub 2} (lag 8), and among females, positive results were observed for NO{sub 2} for lag 8 days, for O{sub 3}, PM{sub 2.5} among all lags. Our study provides evidence of the associations between short-term exposure to air pollution and increased risk of ED visits for upper and lower respiratory diseases in an environment where air pollutant concentrations are relatively low.

54 ENVIRONMENTAL SCIENCES↗