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To describe the clinical implementation and optimization of magnetic resonance imaging (MRI) systems installed in a radiation oncology department for dedicated use in radiotherapy (RT) simulation and treatment planning for pediatric patients.
NASA’s Europa Clipper mission will investigate the Jovian icy moon Europa with a sophisticated payload consisting of a suite of nine instruments. Clipper’s observations will help provide answers to a broad range of scientific objectives related to Europa’s habitability. As the project proceeds through Phase C, we are building confidence in the system’s ability to achieve these science goals by implementing a rigorous payload verification and validation (V&V) program. This paper details the planned structure and implementation of the Europa Clipper payload V&V program as it exists leading up to the project critical design review (CDR), before the bulk of instrument- or payload- level V&V activities have begun. We first explain the context for payload V&V on Europa Clipper, including its interfaces with other parts of the project system. We then describe the taxonomy of V&V concepts and their interrelationships, followed by a discussion on how this framework allows us to codify interfaces, processes, and ideas that are key to a successful V&V program. We focus on key aspects of the planning phases of V&V, especially establishing a complete set of verification items and accurately mapping them into appropriate verification activities. The second half of the paper describes the logistics of implementing this framework onto our actual payload system, including the processes and tools we use to manage and communicate agreements, changes, and risks across the project. We conclude with a reflection on the unique drivers and challenges of the V&V program concept development so far and the work that is planned for phase D implementation.
The U.S. Department of Energy Office of Nuclear Energy (DOE-NE), Office of Fuel Cycle Technology, has established the Used Fuel Disposition Campaign (UFDC) to conduct the research and development activities related to storage, transportation, and disposal of used nuclear fuel and high-level radioactive waste. The mission of the UFDC is to identify alternatives and conduct scientific research and technology development to enable storage, transportation and disposal of used nuclear fuel (UNF) and wastes generated by existing and future nuclear fuel cycles. The UFDC Storage and Transportation staffs are responsible for addressing issues regarding the extended or long-term storage of UNF and its subsequent transportation. The near-term objectives of the Storage and Transportation task are to use a science-based approach to develop the technical bases to support the continued safe and secure storage of UNF for extended periods, subsequent retrieval, and transportation. While low burnup fuel [that characterized as having a burnup of less than 45 gigawatt days per metric tonne uranium (GWD/MTU)] has been stored for nearly three decades, the storage of high burnup used fuels is more recent. The DOE has funded a demonstration project to confirm the behavior of used high burnup fuel under prototypic conditions. The Electric Power Research Institute (EPRI) is leading a project team to develop and implement the Test Plan to collect this data from a UNF dry storage system containing high burnup fuel. The Draft Test Plan for the demonstration outlines the data to be collected; the high burnup fuel to be included; the technical data gaps the data will address; and the storage system design, procedures, and licensing necessary to implement the Test Plan. To provide data that is most relevant to high burnup fuel in dry storage, the design of the test storage system must closely mimic real conditions high burnup SNF experiences during all stages of dry storage: loading, cask drying, inert gas backfilling, and transfer to an Independent Spent Fuel Storage Installation (ISFSI) for multi-year storage. To document the initial condition of the used fuel prior to emplacement in a storage system, “sister ” fuel rods will be harvested and sent to a national laboratory for characterization and archival purposes. This report supports the demonstration by describing how sister rods will be shipped and received at a national laboratory, and recommending basic nondestructive and destructive analyses to assure the fuel rods are adequately characterized for UFDC work. For this report, a hub-and-spoke model is proposed, with one location serving as the hub for fuel rod receipt and characterization. In this model, fuel and/or clad would be sent to other locations when capabilities at the hub were inadequate or nonexistent. This model has been proposed to reduce DOE-NE’s obligation for waste cleanup and decontamination of equipment.
The Demand Response (DR) Dispatch Tool uses price profiles to dispatch demand response resources and create load modifying profiles. These annual profiles are used as inputs to production cost models and regional planning tools (e.g., PROMOD). The tool has been effectively implemented in transmission planning studies conducted by the Western Electricity Coordinating Council via its Transmission Expansion Planning and Policy Committee. The DR Dispatch Tool can properly model the dispatch of DR resources for both reliability and economic conditions.
The Deep Space Network (DSN) Tracking System provides highly precise measurements of spacecraft Doppler and range. It was recently extensively modified as part of the Mark 4-A implementation. The DSN Tracking System as currently implemented, its performance in support of Voyager 2, and plans for new implementation are described.
The Midcourse Space Experiment (MSX) satellite, sponsored by BMDO, is intended to gather broad-band phenomenology data on missiles, plumes, naturally occurring earthlimb backgrounds and deep space backgrounds. In addition the MSX will be used to conduct functional demonstrations of space-based space surveillance. The JHU/Applied Physics Laboratory (APL), located in Laurel, MD, is the integrator and operator of the MSX satellite. APL will conduct all operations related to the MSX and is charged with the detailed operations planning required to implement all of the experiments run on the MSX except the space surveillance experiments. The non-surveillance operations are generally amenable to being defined months ahead of time and being scheduled on a monthly basis. Lincoln Laboratory, Massachusetts Institute of Technology (LL), located in Lexington, MA, is the provider of one of the principle MSX instruments, the Space-Based Visible (SBV) sensor, and the agency charged with implementing the space surveillance demonstrations on the MSX. The planning timelines for the space surveillance demonstrations are fundamentally different from those for the other experiments. They are generally amenable to being scheduled on a monthly basis, but the specific experiment sequence and pointing must be refined shortly before execution. This allocation of responsibilities to different organizations implies the need for a joint mission planning system for conducting space surveillance demonstrations. This paper details the iterative, joint planning system, based on passing responsibility for generating MSX commands for surveillance operations from APL to LL for specific scheduled operations. The joint planning system, including the generation of a budget for spacecraft resources to be used for surveillance events, has been successfully demonstrated during ground testing of the MSX and is being validated for MSX launch within the year. The planning system developed for the MSX forms a model possibly applicable to developing distributed mission planning systems for other multi-use satellites.
Over the course of my internship in the Flight Projects Office of NASA's Launch Services Program (LSP), I worked on two major projects, both of which dealt with updating current systems to make them more accurate and to allow them to operate more efficiently. The first project dealt with the Mission Integration Reporting System (MIRS), a web-accessible database application used to manage and provide mission status reporting for the LSP portfolio of awarded missions. MIRS had not gone through any major updates since its implementation in 2005, and it was my job to formulate a recommendation for the improvement of the system. The second project I worked on dealt with the Mission Plan, a document that contains an overview of the general life cycle that is followed by every LSP mission. My job on this project was to update the information currently in the mission plan and to add certain features in order to increase the accuracy and thoroughness of the document. The outcomes of these projects have implications in the orderly and efficient operation of the Flight Projects Office, and the process of Mission Management in the Launch Services Program as a whole.
A computer program implements stochastic evolutionary algorithms for planning and optimizing collision-free paths for robots and their jointed limbs. Stochastic evolutionary algorithms can be made to produce acceptably close approximations to exact, optimal solutions for path-planning problems while often demanding much less computation than do exhaustive-search and deterministic inverse-kinematics algorithms that have been used previously for this purpose. Hence, the present software is better suited for application aboard robots having limited computing capabilities (see figure). The stochastic aspect lies in the use of simulated annealing to (1) prevent trapping of an optimization algorithm in local minima of an energy-like error measure by which the fitness of a trial solution is evaluated while (2) ensuring that the entire multidimensional configuration and parameter space of the path-planning problem is sampled efficiently with respect to both robot joint angles and computation time. Simulated annealing is an established technique for avoiding local minima in multidimensional optimization problems, but has not, until now, been applied to planning collision-free robot paths by use of low-power computers.
Stereotactic body radiation therapy (SBRT) treatment planning and delivery can be accomplished using a variety of techniques that achieve highly conformal dose distributions. Herein, we describe a template-based automated treatment field approach that enables rapid delivery of more than 20 coplanar fields. A case study is presented to demonstrate how modest adaptations to traditional SBRT planning can be implemented to take clinical advantage of this technology. Treatment was planned for a left-sided lung lesion adjacent to the chest wall using 25 coplanar treatment fields spaced at 11° intervals. The plan spares the contralateral lung and is in compliance with the conformality standards set forth in Radiation Therapy and Oncology Group protocol 0915, and the dose tolerances found in the report of the American Association of Physicists in Medicine Task Group 101. Using a standard template, treatment planning was accomplished in less than 20 minutes, and each 10 Gy fraction was delivered in approximately 5.4 minutes. For those centers equipped with linear accelerators capable of automated treatment field delivery, the use of more than 20 coplanar fields is a viable SBRT planning approach and yields excellent conformality and quality combined with rapid planning and treatment delivery. Although the case study discusses a laterally located lung lesion, this technique can be applied to centrally located tumors with similar results.
This document establishes the Configuration and Data Management Plan for the Thermophysics Facilities Branch (TSF) and describes the implementation of the plan within the organization. Its intent is to control and document changes to facility hardware, software, and facility operating procedures; to control changes to Quality System documents; to ensure that all documents and drawings are current; and to provide for quick retrieval of facility information and documentation while safeguarding original records and documents.
To present a Monte Carlo (MC) beam model and its implementation in a clinical treatment planning system (TPS, Varian Eclipse) for a modified ultrahigh dose-rate electron FLASH radiation therapy (eFLASH-RT) linear accelerator (LINAC) using clinical accessories and geometry.
Purpose: To implement an end-to-end QA test of the radiation therapy imaging, planning and delivery process, aimed to assess the dosimetric agreement accuracy between planned and delivered treatment, in order to identify and correct possible sources of deviation. To establish an internal standard for machine commissioning acceptance. Methods: A test involving all steps of the radiation therapy: imaging, planning and delivery process was designed. The test includes analysis of point dose and planar dose distributions agreement between TPS calculated and measured dose. An ad hoc 16 cm diameter PMMA phantom was constructed with one central and four peripheral bores that can accommodate calibrated electron density inserts. Using Varian Eclipse 10.0 and Elekta XiO 4.50 planning systems, IMRT, RapidArc and 3DCRT with hard and dynamic wedges plans were planned on the phantom and tested. An Exradin A1SL chamber is used with a Keithley 35617EBS electrometer for point dose measurements in the phantom. 2D dose distributions were acquired using MapCheck and Varian aS1000 EPID.Gamma analysis was performed for evaluation of 2D dose distribution agreement using MapCheck software and Varian Portal Dosimetry Application.Varian high energy Clinacs Trilogy, 2100C/CD, 2000CR and low energy 6X/EX where tested.TPS-CT# vs. electron density table were checked for CT-scanners used. Results: Calculated point doses were accurate to 0.127% SD: 0.93%, 0.507% SD: 0.82%, 0.246% SD: 1.39% and 0.012% SD: 0.01% for LoX-3DCRT, HiX-3DCRT, IMRT and RapidArc plans respectively. Planar doses pass gamma 3% 3mm in all cases and 2% 2mm for VMAT plans. Conclusion: Implementation of a simple and reliable quality assurance tool was accomplished. The end-to-end proved efficient, showing excellent agreement between planned and delivered dose evidencing strong consistency of the whole process from imaging through planning to delivery. This test can be used as a first step in beam model acceptance for clinical use.
Cleanup and closure of DOE's Rocky Flats Site in Colorado, which was placed on the CERCLA National Priority List in 1989, was accomplished under CERCLA, RCRA, and the Colorado Hazardous Waste Act (CHWA). The physical cleanup work was completed in late 2005 and all buildings and other structures that composed the Rocky Flats industrial complex were removed from the surface, but remnants remain in the subsurface. Other remaining features include two landfills closed in place with covers, four groundwater treatment systems, and surface water and groundwater monitoring systems. Under the 2006 Corrective Action Decision/Record of Decision for Rocky Flats Plant (US DOE) Peripheral Operable Unit and the Central Operable Unit (CAD/ROD), the response actions selected for the Central Operable Unit (OU) are institutional controls (ICs), physical controls, and continued monitoring and maintenance. The objectives of these ICs were to prevent unacceptable exposure to remaining subsurface contamination and to prevent contaminants from mobilizing to surface water and to prevent interfering with the proper functioning of the engineered components of the remedy. An amendment in 2011 of the 2006 CAD/ROD clarified the ICs to prevent misinterpretation that would prohibit work to manage and maintain the Central OU property. The 2011 amendment incorporated a protocol for a Soil Disturbance Review Plan for work subject to ICs that requires approval from the State and public notification by DOE prior to conducting approved soil-disturbing work. (authors)
In November of 1996, NASA made the decision to fully integrate several areas of robotic and human Mars exploration study and planning. As a result of this decision, requirements for unmanned robotic missions to support human Mars exploration were identified and a plan to meet these requirements was developed. Concrete progress in the implementation of this plan has been made. Three experiments have been selected and are in development for the Mars Surveyor Program 2001 Orbiter and Lander missions which will provide critical data for the planning of human missions to Mars. An Announcement of Opportunity for the Mars Surveyor Program 2003 Lander mission has recently been released which solicited proposals related to planning for a human mission. In order to define HEDS objectives for Mars robotic missions, it is important to understand what information is required as a foundation for mounting a program of exploration of this magnitude. We identify areas of research on robotic missions that will enable future human missions. These areas include Site Selection for Human Missions, Hazards to Human Explorers, Living off the Land, and Testing Critical Technologies in the Mars Environment.
Nearly all data acquired by vehicles on the surface of Mars are returned to Earth via Mars orbiters – more than 1.7 terabits so far. Successful communication between the various spacecraft is achieved via the careful implementation of internationally recognized CCSDS telecommunications protocols and the use of planning and coordination services provided by NASA’s Mars Program Office and the Multimission Ground Systems and Services (MGSS) Program at the Jet Propulsion Laboratory in Pasadena, CA. This modern Mars relay network has evolved since its inception in 2004 with the addition and loss of several missions, but it has fundamentally remained unchanged. Ground interfaces between the various spacecrafts’ mission operations centers on Earth remain largely unique for each participant, each mission maintains its own interfaces with deep space communications networks (e.g. DSN, ESTRACK), which are similar but still unique; and relay sessions at Mars require careful ground planning, coordination, and implementation. This paper will discuss the existing architecture and consider how several technologies may be applied to the next generation of relay services at Mars. Ultimately, these are expected to lead to the implementation of a delay and disruption tolerant network at Mars, a precursor to becoming a major element in an emerging Solar System Internet.
As energy utilities implement climate change mitigation policies, system planners require strategies for achieving affordable emissions reductions. Coordinated planning of electric power and natural gas systems will allow synergistic investments to address cross-sector operational constraints, competing uses for net-zero emissions fuels, and shifts in energy demands across energy carriers. In this study, we develop a novel optimization program that finds the cost-minimizing mix of infrastructure expansion or reduction across gas and electric systems to satisfy sector-specific emissions constraints. Alongside energy supply resources, our framework allows for central-planning of end-use equipment stocks to allow switching between gas and electric appliances upon failure or premature replacement. The proposed model is used to simulate case study scenarios for a benchmark 24-pipe gas network coupled to a 24-node power system test network. We find that electrification of greater than 80% of core gas demands is a component of the least-cost solution for modeled energy systems. Despite this substitution, the gas system is maintained to service difficult-to-electrify customers and to deliver net-zero emissions gas to electricity generators in times of peak electricity demand. Restricting electrification of gas appliances increases reliance on power- to-gas technologies and increases annual costs by 15% in 2040. Neglecting constraints on pipeline blending of hydrogen can produce a misleading result that relies on hydrogen blend fractions of greater than 50%. In all cases, we find the average costs of delivered gas increase nearly 5-fold across the decarbonization transition, highlighting the importance of future work investigating cost-allocation strategies for ensuring an equitable energy transition.
As part of the U.S. Agency for International Development (USAID)-National Renewable Energy Laboratory (NREL) Young Leaders Workforce Training Program in Colombia, participants from Colombia's Energy and Gas Regulatory Commission (CREG) leveraged their training and professional experience to develop a regulatory roadmap for the interconnection and interoperability of increasing integration of distributed energy resources (DERs). CREG was one of four teams selected by the training program development team to receive continued technical assistance and strategic advisory support from the USAID-NREL Partnership for action plan development and implementation. This case study provides an overview of the key activities and outcomes of the technical assistance provided by NREL on the CREG Action Plan, and key next steps for implementation of Colombia's DER Integration Regulatory Roadmap.
Purpose: Potential collisions between the gantry head and the patient or table assembly are difficult to detect in most treatment planning systems. We have developed and implemented a novel software package for the representation of potential gantry collisions with the couch assembly at the time of treatment planning. Methods: Physical dimensions of the Varian Edge linear accelerator treatment head were measured and reproduced using the Visual Python display package. A script was developed for the Pinnacle treatment planning system to generate a file with the relevant couch, gantry, and isocenter positions for each beam in a planning trial. A python program was developed to parse the information from the TPS and produce a representative model of the couch/gantry system. Using the model and the Visual Python libraries, a rendering window is generated for each beam that allows the planner to evaluate the possibility of a collision. Results: Comparison against heuristic methods and direct verification on the machine validated the collision model generated by the software. Encounters of <1 cm between the gantry treatment head and table were visualized as collisions in our virtual model. Visual windows were created depicting the angle of collision for each beam, including the anticipated table coordinates. Visual rendering of a 6 arc trial with multiple couch positions was completed in under 1 minute, with network bandwidth being the primary bottleneck. Conclusion: The developed software allows for quick examination of possible collisions during the treatment planning process and helps to prevent major collisions prior to plan approval. The software can easily be implemented on future planning systems due to the versatility and platform independence of the Python programming language. Further integration of the software with the treatment planning system will allow the possibility of patient-gantry collision detection for a range of treatment machines.