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At least 307 records · Page 17

TU-EF-204-03: Task-Based KV and MAs Optimization for Radiation Dose Reduction in CT: From FBP to Statistical Model-Based Iterative Reconstruction (MBIR)

Purpose: The introduction of the highly nonlinear MBIR algorithm to clinical CT systems has made CNR an invalid metric for kV optimization. The purpose of this work was to develop a task-based framework to unify kV and mAs optimization for both FBP- and MBIR-based CT systems. Methods: The kV-mAs optimization was formulated as a constrained minimization problem: to select kV and mAs to minimize dose under the constraint of maintaining the detection performance as clinically prescribed. To experimentally solve this optimization problem, exhaustive measurements of detectability index (d’) for a hepatic lesion detection task were performed at 15 different mA levels and 4 kV levels using an anthropomorphic phantom. The measured d’ values were used to generate an iso-detectability map; similarly, dose levels recorded at different kV-mAs combinations were used to generate an iso-dose map. The iso-detectability map was overlaid on top of the iso-dose map so that for a prescribed detectability level d’, the optimal kV-mA can be determined from the crossing between the d’ contour and the dose contour that corresponds to the minimum dose. Results: Taking d’=16 as an example: the kV-mAs combinations on the measured iso-d’ line of MBIR are 80–150 (3.8), 100–140 (6.6), 120–150 (11.3), and 140–160 (17.2), where values in the parentheses are measured dose values. As a Result, the optimal kV was 80 and optimal mA was 150. In comparison, the optimal kV and mA for FBP were 100 and 500, which corresponded to a dose level of 24 mGy. Results of in vivo animal experiments were consistent with the phantom results. Conclusion: A new method to optimize kV and mAs selection has been developed. This method is applicable to both linear and nonlinear CT systems such as those using MBIR. Additional dose savings can be achieved by combining MBIR with this method. This work was partially supported by an NIH grant R01CA169331 and GE Healthcare. K. Li, D. Gomez-Cardona, M. G. Lubner: Nothing to disclose. P. J. Pickhardt: Co-founder, VirtuoCTC, LLC Stockholder, Cellectar Biosciences, Inc. G.-H. Chen: Research funded, GE Healthcare; Research funded, Siemens AX.

60 APPLIED LIFE SCIENCES↗

TU-EF-210-04: AAPM Task Groups in Interventional Ultrasound Imaging and Therapy

The use of therapeutic ultrasound to provide targeted therapy is an active research area that has a broad application scope. The invited talks in this session will address currently implemented strategies and protocols for both hyperthermia and ablation applications using therapeutic ultrasound. The role of both ultrasound and MRI in the monitoring and assessment of these therapies will be explored in both pre-clinical and clinical applications. Katherine Ferrara: High Intensity Focused Ultrasound, Drug Delivery, and Immunotherapy Rajiv Chopra: Translating Localized Doxorubicin Delivery to Pediatric Oncology using MRI-guided HIFU Elisa Konofagou: Real-time Ablation Monitoring and Lesion Quantification using Harmonic Motion Imaging Keyvan Farahani: AAPM Task Groups in Interventional Ultrasound Imaging and Therapy Learning Objectives: Understand the role of ultrasound in localized drug delivery and the effects of immunotherapy when used in conjunction with ultrasound therapy. Understand potential targeted drug delivery clinical applications including pediatric oncology. Understand the technical requirements for performing targeted drug delivery. Understand how radiation-force approaches can be used to both monitor and assess high intensity focused ultrasound ablation therapy. Understand the role of AAPM task groups in ultrasound imaging and therapies. Chopra: Funding from Cancer Prevention and Research Initiative of Texas (CPRIT), Award R1308 Evelyn and M.R. Hudson Foundation; Research Support from Research Contract with Philips Healthcare; COI are Co-founder of FUS Instruments Inc Ferrara: Supported by NIH, UCDavis and California (CIRM and BHCE) Farahani: In-kind research support from Philips Healthcare.

60 APPLIED LIFE SCIENCES↗

Monte Carlo reference data sets for imaging research: Executive summary of the report of AAPM Research Committee Task Group 195

The use of Monte Carlo simulations in diagnostic medical imaging research is widespread due to its flexibility and ability to estimate quantities that are challenging to measure empirically. However, any new Monte Carlo simulation code needs to be validated before it can be used reliably. The type and degree of validation required depends on the goals of the research project, but, typically, such validation involves either comparison of simulation results to physical measurements or to previously published results obtained with established Monte Carlo codes. The former is complicated due to nuances of experimental conditions and uncertainty, while the latter is challenging due to typical graphical presentation and lack of simulation details in previous publications. In addition, entering the field of Monte Carlo simulations in general involves a steep learning curve. It is not a simple task to learn how to program and interpret a Monte Carlo simulation, even when using one of the publicly available code packages. This Task Group report provides a common reference for benchmarking Monte Carlo simulations across a range of Monte Carlo codes and simulation scenarios. In the report, all simulation conditions are provided for six different Monte Carlo simulation cases that involve common x‐ray based imaging research areas. The results obtained for the six cases using four publicly available Monte Carlo software packages are included in tabular form. In addition to a full description of all simulation conditions and results, a discussion and comparison of results among the Monte Carlo packages and the lessons learned during the compilation of these results are included. This abridged version of the report includes only an introductory description of the six cases and a brief example of the results of one of the cases. This work provides an investigator the necessary information to benchmark his/her Monte Carlo simulation software against the reference cases included here before performing his/her own novel research. In addition, an investigator entering the field of Monte Carlo simulations can use these descriptions and results as a self‐teaching tool to ensure that he/she is able to perform a specific simulation correctly. Finally, educators can assign these cases as learning projects as part of course objectives or training programs.

Sechopoulos, Ioannis↗

Ongoing quality control in digital radiography: Report of AAPM Imaging Physics Committee Task Group 151

Quality control (QC) in medical imaging is an ongoing process and not just a series of infrequent evaluations of medical imaging equipment. The QC process involves designing and implementing a QC program, collecting and analyzing data, investigating results that are outside the acceptance levels for the QC program, and taking corrective action to bring these results back to an acceptable level. The QC process involves key personnel in the imaging department, including the radiologist, radiologic technologist, and the qualified medical physicist (QMP). The QMP performs detailed equipment evaluations and helps with oversight of the QC program, the radiologic technologist is responsible for the day-to-day operation of the QC program. The continued need for ongoing QC in digital radiography has been highlighted in the scientific literature. The charge of this task group was to recommend consistency tests designed to be performed by a medical physicist or a radiologic technologist under the direction of a medical physicist to identify problems with an imaging system that need further evaluation by a medical physicist, including a fault tree to define actions that need to be taken when certain fault conditions are identified. The focus of this final report is the ongoing QC process, including rejected image analysis, exposure analysis, and artifact identification. These QC tasks are vital for the optimal operation of a department performing digital radiography.

60 APPLIED LIFE SCIENCES↗

Accuracy and calibration of integrated radiation output indicators in diagnostic radiology: A report of the AAPM Imaging Physics Committee Task Group 190

Due to the proliferation of disciplines employing fluoroscopy as their primary imaging tool and the prolonged extensive use of fluoroscopy in interventional and cardiovascular angiography procedures, “dose-area-product” (DAP) meters were installed to monitor and record the radiation dose delivered to patients. In some cases, the radiation dose or the output value is calculated, rather than measured, using the pertinent radiological parameters and geometrical information. The AAPM Task Group 190 (TG-190) was established to evaluate the accuracy of the DAP meter in 2008. Since then, the term “DAP-meter” has been revised to air kerma-area product (KAP) meter. The charge of TG 190 (Accuracy and Calibration of Integrated Radiation Output Indicators in Diagnostic Radiology) has also been realigned to investigate the “Accuracy and Calibration of Integrated Radiation Output Indicators” which is reflected in the title of the task group, to include situations where the KAP may be acquired with or without the presence of a physical “meter.” To accomplish this goal, validation test protocols were developed to compare the displayed radiation output value to an external measurement. These test protocols were applied to a number of clinical systems to collect information on the accuracy of dose display values in the field.

60 APPLIED LIFE SCIENCES↗

TH-A-BRC-00: New Task Groups for External Beam QA: An Overview

AAPM TG-135U1 QA for Robotic Radiosurgery - Sonja Dieterich Since the publication of AAPM TG-135 in 2011, the technology of robotic radiosurgery has rapidly developed. AAPM TG-135U1 will provide recommendations on the clinical practice for using the IRIS collimator, fiducial-less real-time motion tracking, and Monte Carlo based treatment planning. In addition, it will summarize currently available literature about uncertainties. Learning Objectives: Understand the progression of technology since the first TG publication Learn which new QA procedures should be implemented for new technologies Be familiar with updates to clinical practice guidelines AAPM TG-178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance - Steven Goetsch Purpose: AAPM Task Group 178 Gamma Stereotactic Radiosurgery Dosimetry and Quality Assurance was formed in August, 2008. The Task Group has 12 medical physicists, two physicians and two consultants. Methods: A round robin dosimetry intercomparison of proposed ionization chambers, electrometer and dosimetry phantoms was conducted over a 15 month period in 2011 and 2012 (Med Phys 42, 11, Nov, 2015). The data obtained at 9 institutions (with ten different Elekta Gamma Knife units) was analyzed by the lead author using several protocols. Results: The most consistent results were obtained using the Elekta ABS 16cm diameter phantom, with the TG-51 protocol modified as recommended by Alfonso et al (Med Phys 35, 11, Nov 2008). A key white paper (Med Phys, in press) sponsored by Elekta Corporation, was used to obtain correction factors for the ionization chambers and phantoms used in this intercomparison. Consistent results were obtained for both Elekta Gamma Knife Model 4C and Gamma Knife Perfexion units as measured with each of two miniature ionization chambers. Conclusion: The full report gives clinical history and background of gamma stereotactic radiosurgery, clinical examples and history, quality assurance recommendations and outline of possible dosimetry protocols. The report will be reviewed by the AAPM Working Group on Recommendations for Radiotherapy External Beam Quality Assurance and then by the AAPM Science Council before publication in Medical Physics Survey of possible calibration protocols for calibration of Gamma Stereotactic Radiosurgery (GSR) devices Overview of modern Quality Assurance techniques for GSR AAPM TG-218 Tolerance Levels and Methodologies for IMRT Verification QA - Moyed Miften Patient-specific IMRT QA measurement is a process designed to identify discrepancies between calculated and delivered doses. Error tolerance limits are not well-defined or consistently applied across centers. The AAPM TG-218 report has been prepared to improve the understanding and consistency of this process by providing recommendations for methodologies and tolerance limits in patient-specific IMRT QA. Learning Objectives: Review measurement methods and methodologies for absolute dose verification Provide recommendations on delivery methods, data interpretation, the use of analysis routines and choice of tolerance limits for IMRT QA Sonja Dieterich has a research agreement with Sun Nuclear Inc. Steven Goetsch is a part-time consultant for Elekta.

60 APPLIED LIFE SCIENCES↗

TH-AB-207A-09: Tailoring TCM Schemes to a Task: Evaluating the Impact of Customized TCM Profiles On Detection of Lung Nodules in Simulated CT Lung Cancer Screening

Purpose: Recent work has shown that current TCM profile designs boost detection of low-contrast lung lesions in the lung apices, but yield reduced detection performance in the mid and lower lung regions relative to fixed tube current cases. This observed imbalance suggests that the TCM scheme might be tailored in new ways to maximize nodule detection throughout the entire lung. In this work, we begin a preliminary investigation into custom TCM profiles in an attempt to achieve uniform lesion detection throughout the extent of the lung. Methods: Low-contrast (25HU), 6mm nodules representing ground glass opacities were simulated at 1mm intervals over the length the lungs in a voxelized model of the XCAT phantom, one nodule per lung, per simulated scan. Voxel values represented attenuation values at 80keV. CT projection data was created by simulating a finite focal spot and using Joseph’s method for forward projection; scanner geometry was that of the Siemens Sensation 64 and the X-ray source was simulated as an 80keV monochromatic beam. Noise realizations were created using Poisson statistics, a realistic bowtie filter and varying tube current. 500 noise realizations were created for the custom TCM designs. All reconstruction was done with FreeCT-wFBP. An SKE/BKE task was used in conjunction with a 2D Hotelling Observer to calculate area-under-the-curve (AUC) as a proxy for “detectability.” AUC was plotted as a function of nodule Z-location to create a “detectability map.” The detectability map for the custom TCM curve was qualitatively assessed relative to previous results for the fixed TC and clinical TCM cases for uniformity. Results: Detection uniformity was improved throughout the mid and lower lungs, however detection remained disproportionately high in the upper lung region. Conclusion: Detection uniformity was improved with a custom TC profile. Future work will incorporate an analytic, task-specific approach to optimize the TC scheme for nodule detection. J. Hoffman: Part-time intern, Toshiba Medical Research Institute; M. McNitt-Gray: Institutional research agreement, Siemens Healthcare; Past recipient, research grant support, Siemens Healthcare; Consultant, Toshiba America Medical Systems; Consultant, Samsung Electronics; F. Noo: Institutional research agreement, Siemens Healthcare; Receives research funding from Siemens Healthcare.

60 APPLIED LIFE SCIENCES↗

Extensive cellular multi-tasking within Bacillus subtilis biofilms

Bacillus subtilis is a soil-dwelling bacterium that can form biofilms, or communities of cells surrounded by a self-produced extracellular matrix. In biofilms, genetically identical cells often exhibit heterogeneous transcriptional phenotypes, so that subpopulations of cells carry out essential yet costly cellular processes that allow the entire population to thrive. Surprisingly, the extent of phenotypic heterogeneity and the relationships between subpopulations of cells within biofilms of even in well-studied bacterial systems like B. subtilis remains largely unknown. To determine relationships between these subpopulations of cells, we created 182 strains containing pairwise combinations of fluorescent transcriptional reporters for the expression state of 14 different genes associated with potential cellular subpopulations. We determined the spatial organization of the expression of these genes within biofilms using confocal microscopy, which revealed that many reporters localized to distinct areas of the biofilm, some of which were co-localized. We used flow cytometry to quantify reporter co-expression, which revealed that many cells “multi-task,” simultaneously expressing two reporters. These data indicate that prior models describing B. subtilis cells as differentiating into specific cell types, each with a specific task or function, were oversimplified. Only a few subpopulations of cells, including surfactin and plipastatin producers, as well as sporulating and competent cells, appear to have distinct roles based on the set of genes examined here. These data will provide us with a framework with which to further study and make predictions about the roles of diverse cellular phenotypes in B. subtilis biofilms.

59 BASIC BIOLOGICAL SCIENCES↗

A Comparison of Neuromorphic Classification Tasks

A variety of neural network models and machine learning techniques have arisen over the past decade, and their successes with image classification have been stunning. With other classification tasks, selecting and configuring a neural network solution is not straightforward. In this paper, we evaluate and compare a variety of neural network models, trained by a variety of machine learning techniques, on a variety of classification tasks. While Deep Learning typically exhibits the best classification accuracy, we note the promise of Reservoir Computing, and evolutionary optimization on spiking neural networks. In many cases, these technologies perform as well as, or better than Deep Learning, and the resulting networks are much smaller than their Deep Learning counterparts.

Reynolds, John↗

LabVIEW Task Manager v. 1.10.0

LabVIEW Task Manager is a debugging tool for use during code development in the National Instruments (NI) LabVIEW® IDE. While providing a dynamic & big-picture view of running code, an expandable/collapsible tree diagram displays detailed information (both static and dynamic) on all VIs in memory, belonging to a selected project/target. It allows for interacting with single or multiple selected VIs at a time, providing significant benefits while troubleshooting, and has the following features: Look & Feel similar to Windows® Task Manager; Selection of project/target; Lists all VIs in memory, grouped by class/library; Searches for and enumerates clones in memory; DropIn VI for including dynamically referenced clones (Clone Beacon); 'Refresh Now' (F5) re-reads all VIs in memory and adds new ones to the tree; Displays VI name, owning class/library, state, path, data size & code size; Displays VI FP Behavior, Reentrant?, Reentrancy Type, Paused? & Highlight?; Sort by any column, including by library name; Filter by item types vi, ctl, and vit/ctt; Filter out vi.lib and global VIs; Tracking of, and ability to toggle, execution highlighting on multiple selected VIs; Tracking of paused VIs with ability to Pause/Resume/TogglePause multiple selected VIs; DropIn VI for pausing on a condition; If a clone initiates a pause, a different pause symbol is used for all clones of that same reentrant original VI; Select multiple VIs and open or close their FPs or BDs; Double Click a VI from the tree to bring the BD (first choice) or FP to front, if already open; and Select multiple top-level VIs and Abort them.

Vargo, TimothyD.↗

Cyber-CHAMP Task Analysis Survey Tool

Cyber-CHAMP Task analysis survey tool is a web-hosted code platform for an individual to select their every day tasking, based on industry documentation and standards, and produce an education and training mapping to provide them the proper associated cyber competency level(s).

Stailey, ShaneD.↗

Simultaneously improving accuracy and computational cost under parametric constraints in materials property prediction tasks

Abstract Modern data mining techniques using machine learning (ML) and deep learning (DL) algorithms have been shown to excel in the regression-based task of materials property prediction using various materials representations. In an attempt to improve the predictive performance of the deep neural network model, researchers have tried to add more layers as well as develop new architectural components to create sophisticated and deep neural network models that can aid in the training process and improve the predictive ability of the final model. However, usually, these modifications require a lot of computational resources, thereby further increasing the already large model training time, which is often not feasible, thereby limiting usage for most researchers. In this paper, we study and propose a deep neural network framework for regression-based problems comprising of fully connected layers that can work with any numerical vector-based materials representations as model input. We present a novel deep regression neural network, iBRNet, with branched skip connections and multiple schedulers, which can reduce the number of parameters used to construct the model, improve the accuracy, and decrease the training time of the predictive model. We perform the model training using composition-based numerical vectors representing the elemental fractions of the respective materials and compare their performance against other traditional ML and several known DL architectures. Using multiple datasets with varying data sizes for training and testing, We show that the proposed iBRNet models outperform the state-of-the-art ML and DL models for all data sizes. We also show that the branched structure and usage of multiple schedulers lead to fewer parameters and faster model training time with better convergence than other neural networks. Scientific contribution: The combination of multiple callback functions in deep neural networks minimizes training time and maximizes accuracy in a controlled computational environment with parametric constraints for the task of materials property prediction.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Near-Zero Emissions Oxy-Combustion Flue Gas Purification Task 2: SOx/Nox/Hg Removal for High Sulfur Coal

The goal of this project is to develop a near-zero emissions flue gas purification technology for existing PC (pulverized coal) power plants that are retrofitted with oxy-combustion technology. The objective of Task 2 of this project was to evaluate an alternative method of SOx, NOx and Hg removal from flue gas produced by burning high sulfur coal in oxy-combustion power plants. The goal of the program was not only to investigate a new method of flue gas purification but also to produce useful acid byproduct streams as an alternative to using a traditional FGD and SCR for flue gas processing. During the project two main constraints were identified that limit the ability of the process to achieve project goals. 1) Due to boiler island corrosion issues >60% of the sulfur must be removed in the boiler island with the use of an FGD. 2) A suitable method could not be found to remove NOx from the concentrated sulfuric acid product, which limits sale-ability of the acid, as well as the NOx removal efficiency of the process. Given the complexity and safety issues inherent in the cycle it is concluded that the acid product would not be directly saleable and, in this case, other flue gas purification schemes are better suited for SOx/NOx/Hg control when burning high sulfur coal, e.g. this project's Task 3 process or a traditional FGD and SCR.

01 COAL, LIGNITE, AND PEAT↗

Report on Project Action Sheet PP05 task 3 between the U.S. Department of Energy and the Republic of Korea Ministry of Education, Science, and Technology (MEST)

This report documents the results of Task 3 of Project Action Sheet PP05 between the United States Department of Energy (DOE) and the Republic of Korea (ROK) Ministry of Education, Science, and Technology (MEST) for Support with Review of an ROK Risk Evaluation Process. This task was to have Sandia National Laboratories collaborate with the Korea Institute of Nuclear Nonproliferation and Control (KINAC) on several activities concerning how to determine the Probability of Neutralization, P N , and the Probability of System Effectiveness, P E , to include: providing descriptions on how combat simulations are used to determine P N and P E ; comparisons of the strengths and weaknesses of two neutralization models (the Neutralization.xls spreadsheet model versus the Brief Adversary Threat-Loss Estimator (BATLE) software); and demonstrating how computer simulations can be used to determine P N . Note that the computer simulation used for the demonstration was the Scenario Toolkit And Generation Environment (STAGE) simulation, which is a stand-alone synthetic tactical simulation sold by Presagis Canada Incorporated. The demonstration is provided in a separate Audio Video Interleave (.AVI) file.

Snell, Mark Kamerer↗

Regulatory Assistance, Stakeholder Outreach, and Coastal and Marine Spatial Planning Activities In Support Marine and Hydrokinetic Energy Deployment: Task 2.1.7 Permitting and Planning Fiscal Year 2012 Year-End Report

This fiscal year 2012 year-end report summarizes activities carried out under DOE Water Power task 2.1.7, Permitting and Planning. Activities under Task 2.1.7 address the concerns of a wide range of stakeholders with an interest in the development of the MHK industry, including regulatory and resource management agencies, tribes, NGOs, and industry.

54 ENVIRONMENTAL SCIENCES↗

Beryllium Dynamic Strength Measurements (Report on Task 1, Agreement #B590737)

Goal of the work under Agreement #B590737 is development of experimentally justified model of beryllium shear strength of American production ( Be S200F ) in the pressure range of ∼10÷60 GPa and strain rates up to $\dot{ε_i}$ ≈10 6 s -1 . The Be shear strength models, which are available in this range of parameters, have no sufficiently reliable experimental justification. Therefore it is planned to perform tests using the dynamic method of perturbations with shockless loading of the investigated Be S200F samples up to pressure P m ≈55 GPa. Growth of specified perturbations will be recorded by pulse X-ray radiography. The existing relaxation model of beryllium strength will be corrected basing on test results. Besides, the model should also describe the other published results of tests with investigation of dynamic properties of beryllium. Also it is planned to perform two tests with loading of beryllium samples up to pressure P∼50÷60 GPa with recovery followed by metallographic investigation. Goal of the metallographic investigation is determination of peculiarities of high-rate deformation of Be , determination of density of dislocations and twins in the loaded samples. These data will allow developing a more justified constitutive equation (the strength model). Objective of this Task of Agreement #B590737 consists of review of the published data on deformation and shear strength of Be , as well as numerical-theoretical justification of the tests, which will be performed under the frameworks of Task 3 of the Agreement. Besides, this report includes the earlier published data on measurements of velocities of vanadium liners accelerated by explosive two-stage device.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

Electric Vehicle Preparedness: Task 2, Identification of Vehicles for Installation of Data Loggers for Marine Corps Base Camp Lejeune

In Task 1, a survey was completed of the inventory of non-tactical fleet vehicles at the Marine Corps Base Camp Lejeune (MCBCL) to characterize the fleet. This information and characterization was used to select vehicles for further monitoring, which involves data logging of vehicle movements in order to identify the vehicle’s mission and travel requirements. Individual observations of these selected vehicles provide the basis for recommendations related to PEV adoption. It also identifies whether a battery electric vehicle or plug-in hybrid electric vehicle (collectively referred to as PEVs) can fulfill the mission requirements and provides observations related to placement of PEV charging infrastructure. This report provides the list of vehicles selected by MCBCL and Intertek for further monitoring and fulfills the Task 2 requirements.

33 ADVANCED PROPULSION SYSTEMS↗

Electric Vehicle Preparedness: Task 1, Assessment of Fleet Inventory for Marine Corps Base Camp Lejeune

Several U.S. Department of Defense-based studies were conducted to identify potential U.S. Department of Defense transportation systems that are strong candidates for introduction or expansion of plug-in electric vehicles (PEVs). Task 1 included a survey of the inventory of non-tactical fleet vehicles at the Marine Corps Base Camp Lejeune (MCBCL) to characterize the fleet. This information and characterization will be used to select vehicles for monitoring that takes place during Task 2. This monitoring involves data logging of vehicle operation in order to identify the vehicle’s mission and travel requirements. Individual observations of these selected vehicles provide the basis for recommendations related to PEV adoption. It also identifies whether a battery electric vehicle or plug-in hybrid electric vehicle (collectively referred to as PEVs) can fulfill the mission requirements and provides observations related to placement of PEV charging infrastructure.

33 ADVANCED PROPULSION SYSTEMS↗