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Tech Beat - May 11, 2010

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Editor: Michael Baum
Date created: July 7, 2010
Date Modified: July 7, 2010 
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Meet Phannie, NIST's Standard 'Phantom' for Calibrating MRI Machines

Magnetic resonance imaging (MRI)--a widely used medical tool that relies on magnetic fields and radio waves to visualize the body's internal structures, especially soft tissues--may soon become even more useful.

phannie in MRI scanner
phannie

Phannie is the first “phantom” for calibrating magnetic resonance imaging (MRI) machines that is traceable to standardized values. The plastic sphere is about the size of a person’s head and filled with 100 smaller spheres used as contrast-enhancing agents and measurement reference markers. NIST researchers in Boulder, Colo., built Phannie and tested it on an MRI scanner at the University of Colorado Brain Imaging Center.

Credit: S. Russek/NIST
View hi-resolution top image and bottom image.

The National Institute of Standards and Technology (NIST) has unveiled the first “phantom” for calibrating MRI machines that is traceable to standardized values. The prototype, named Phannie, was developed in collaboration with the standards committee of the International Society for Magnetic Resonance in Medicine (ISMRM).

Traceable MRI calibrations are expected to enable accurate, quantitative measurements of tumors and other disease markers that can be reproduced across many different patients, scanners and clinics over time—and potentially reduce medical costs.

Displayed at the annual ISMRM meeting this past week,* the NIST phantom is a plastic sphere about the size of a person’s head, filled with water-bathed grids of 100 small plastic spheres containing various salt solutions that become magnetized in a magnetic field. By making MRI scans of Phannie, users can evaluate the image contrast, resolution, and accuracy of distance and volume measurements. A machine’s performance can be compared to standards, to other MRI machines, and to itself over time.

MRI scanner performance may drift, or different machines may produce different images of the same patient. The new phantom is intended to help generate more accurate and consistent images, help validate disease mechanisms and treatments, and reduce medical costs by improving image quality and reliability. The phantom will assist multisite clinical trials that use quantitative MRI to test the efficacy of novel drugs.

A number of specialized MRI phantoms already exist; the need for new ones to support quantitative studies was recognized at a NIST workshop in 2006.** NIST’s is the first phantom designed to ensure that MRI system properties and image data are traceable to international system of units (SI) standards. The ISMRM Ad Hoc Committee on Standards for Quantitative MR defined the phantom requirements and values. NIST modeled and built the prototype device and assured the accuracy of measured quantities. NIST also developed and tested various solutions used in the mini-spheres as contrast-enhancing agents and measurement reference markers. Phannie will now undergo testing at other institutions for about four months.

Stephen Russek, the physicist leading NIST’s part of the project, says the phantom is intended to be not only accurate and traceable but also physically stable and affordable, so that it can become as widely used in MRI machines as seatbelts are in cars. He demonstrated the durability of the mini-spheres by bouncing one on the floor. Materials for Phannie cost $10,000, but hopefully, in mass production the cost per phantom can be reduced to $2,000, he says.

“If it’s accurate, reliable and affordable, then you have a way to measure the accuracy of MRI scanners all across the country,” Russek says. “If used routinely, it will allow us to get a complete snapshot of the quality and consistency of scanning.”

* Joint annual meeting of the International Society for Magnetic Resonance in Medicine and the European Society for Magnetic Resonance in Medicine and Biology, May 1-7, 2010, Stockholm, Sweden.

** U.S. Measurement System Workshop on Imaging as a Biomarker: Standards for Change Measurements in Therapy, Sept. 14-15, 2006, Gaithersburg, Md.

Media Contact: Laura Ost, laura.ost@nist.gov, 303-497-4880

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NIST Releases Successor to Venerable Handbook of Math Functions

GAITHERSBURG, Md. -- After a decade of preparation, the U.S. Commerce Department's National Institute of Standards and Technology (NIST) has released the Digital Library of Mathematical Functions (DLMF) and its printed companion, the NIST Handbook of Mathematical Functions, the much-anticipated successors to the agency's most widely cited publication of all time. These modernized reference works contain a comprehensive set of mathematical tools useful for any and all specialists who work with mathematical modeling and computation.

The works comprise a complete update and expansion of the 1964 Handbook of Mathematical Functions edited by Milton Abramowitz and Irene Stegun of NIST. That Handbook quickly became an indispensable reference for scientists and engineers who use the tools of applied mathematics in their work. While the 1964 volume has sold an estimated 1 million copies and still averages more than 1,600 citations per year in scientific papers, NIST embarked on the new work in response to advances in electronic information exchange as well as in mathematics itself.

The new 36-chapter tome is designed to be the definitive reference work on applied mathematics' "special functions," the term collectively used to describe the most important and widely employed mathematical functions. Special functions appear whenever natural phenomena are studied, engineering problems are formulated, and computer simulations are performed. They also crop up in statistics, financial models, and economic analysis.

The DLMF provides critical reference information needed to use these functions in practice, such as their precise definitions, alternative ways to represent them mathematically, illustrations of how the functions behave at extreme values, and their relationships to other functions and concepts.

"When studying a phenomenon, experts want to know more than just how to describe it qualitatively," says NIST's Dan Lozier, one of the works' editors. "They need to know its relationships to other phenomena and get insight into its behavior. For this they need mathematics. And as they progress with their research, whether it is in mathematics, science, or engineering, they want to know how to perform all the necessary mathematical analyses and computations, from conception to conclusion. The DLMF will help with all these tasks."

The new work differs from the 1964 publication in several respects. It includes information about additional special functions that have more recently come to prominence in applied mathematics, the physical sciences and engineering, as well as in other fields. It has also been subjected to a more rigorous editorial process, complete with independent validation of all technical material. Perhaps the greatest difference, however, is its transformation into a Web-based resource.

Graph showing part of the complex number phase of the gamma function and a related function.

Graph showing part of the complex number phase of the gamma function and a related function. One of the most important of the "special functions" discovered in the 18th century, the gamma function is related to the more familiar factorial function and plays a role in a wide variety of applications of probability and statistics. Here the pattern resembles that of fluid flow near the end of a line of vortices.

Credit: NIST

The online DLMF, freely available on the Web, includes visual aids that provide qualitative information on the behavior of mathematical functions, such as interactive tools for rotating and zooming in on three-dimensional representations. These visualizations can be explored with free browsers and plugins for PC, Mac and Linux systems. Confused about the symbols in an equation? Just click on the symbol to be led to its definition. The DLMF also provides references to or hints for the proofs of all mathematical statements, offers advice on methods for computing mathematical functions, and provides active links to available software and references. It also features a powerful search engine.

With more than 8,000 equations and nearly 500 figures, the DLMF has about twice the amount of technical material of the 1964 publication. The lengthy tables of function values that took up a great deal of the earlier work – a necessity before the advent of desktop computers – are no more, and the purely mathematical content is now much greater.

"This is a much more complete package for the user," Lozier says. "We anticipate the DLMF to be a useful resource for everyone who has benefited from the 1964 publication, and expect that it will find new audiences among biologists, data security specialists, and every other branch of science that employs computer-based models."

Compiled and extensively edited at NIST, the DLMF received initial seed money from the National Science Foundation and resulted from contributions of more than 50 subject-area experts worldwide. The NIST editors are Frank W. J. Olver, Daniel W. Lozier, Ronald F. Boisvert and Charles W. Clark.

The DLMF is available at http://dlmf.nist.gov/. Its 967-page printed companion, the NIST Handbook of Mathematical Functions (ISBN 9780521192255), is published by Cambridge University Press.

Media Contact: Chad Boutin, boutin@nist.gov, 301-975-4261

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Comments Sought on Updated Guide for Assessing Federal IT Security Controls

The National Institute of Standards and Technology (NIST) has issued the final draft of Special Publication 800-53A, Revision 1, Guide for Assessing Security Controls in Federal Information Systems and Organizations, and is seeking public comments. The publication provides guidelines for developing security assessment plans and associated security control assessment procedures that are consistent with the recently revised foundational Federal Information Security Management Act (FISMA) publication, NIST Special Publication 800-53, Revision 3.

NIST has been working with its partners in the Joint Task Force Transformation Initiative Working Group—the Office of the Director of National Intelligence (ODNI), the Department of Defense (DOD) and the Committee on National Security Systems (CNSS)—for three years to develop a unified information security framework for the federal government and its contractors. The first publication developed by the Joint Task Force was SP 800-53, Revision 3, Recommended Security Controls for Federal Information Systems and Organizations, which was published in August 2009.

The final draft of SP 800-53A, Revision 1, is the third in the series of new joint publications and incorporates best practices in information security from the organizations in the Joint Task Force. The guideline includes security control assessment procedures for both national security and non-national security systems and is intended to support a variety of assessment activities in all phases of the system development life cycle, including development, implementation and operation.

SP 800-53A, Revision 1, updates assessment procedures for all security controls and control enhancements in SP 800-53, Revision 3, including the Program Management family controls. The update also eliminates the Extended Assessment Procedure, simplifies the common nomenclature for depth and coverage attributes, and eliminates the L, M and H designators (used to indicate low-, moderate- and high-impact information systems) in the assessment procedures catalog. These simplifications will provide organizations with greater flexibility in selecting appropriate assessment methods, such as those supporting information system developments, initial and ongoing security authorizations, and continuous monitoring.

“Changes in SP 800-53A, Revision 1, are part of a larger strategic initiative to focus on enterprise-wide, near real-time risk management,” explains FISMA Implementation Project Leader Ron Ross. “Achieving the objective of near real-time risk management means that organizations must have the flexibility to tailor their assessment activities based on where the information system is in its life cycle, from initial development to continuous monitoring in operational environments.”

The increased flexibility in the revised publication empowers organizations to place the appropriate emphasis on the assessment process throughout the system development life cycle. Organizations can both increase the level of assessment in the beginning of system development to identify weaknesses and deficiencies early and promote cost-effective solutions and customize assessment activities during continuous monitoring to emphasize assessing security controls that provide the greatest return on investment.

The public is encouraged to read SP 800-53A, Revision 1, available at http://csrc.nist.gov/publications/PubsDrafts.html#800-53A-rev1, and to submit comments to sec-cert@nist.gov by June 4, 2010.

Media Contact: Evelyn Brown, evelyn.brown@nist.gov, 301-975-5661

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Landmark Study Shows How Size of Fire Crew Influences Saving Lives and Property

A landmark study coordinated by the National Institute of Standards and Technology (NIST) is the first to put numbers to the effect of changing the size of fire-fighting crews responding to residential fires. Performed by a broad coalition in the scientific, firefighting and public-safety communities, the study quantifies the effects of crew sizes and arrival times on the fire service’s lifesaving and firefighting operations for residential fires. Until now, little scientific data have been available.

The research team found that four-person firefighting crews were able to complete 22 essential firefighting and rescue tasks in a typical residential structure 30 percent faster than two-person crews and 25 percent faster than three-person crews. “The results from this rigorous scientific study on the most common and deadly fires in the country—those in single-family residences—provide quantitative data to fire chiefs and public officials responsible for determining safe staffing levels, station locations and appropriate funding for community and firefighter safety,” says NIST’s Jason Averill, one of the study’s principal investigators.

The four-person crews were able to deliver water to a similar-sized fire 16 percent faster than the two-person crews and 6 percent faster than three-person crews, steps that help to reduce property damage and lower danger to the firefighters. The four-person crews were able to complete search and rescue 30 percent faster than two-person crews and 5 percent faster than three-person crews. Five-person crews were faster than four-person crews in several key tasks. The benefits of five-person crews have also been documented by other researchers for fires in medium- and high-hazard structures, such as high-rise buildings, commercial properties, factories and warehouses.

This study explored fires in a residential structure, where the vast majority of fatal fires occur. The researchers built a two-story, 2,000-square-foot test facility at the Montgomery County Public Safety Training Academy in Rockville, Md. Fire crews from Montgomery County, Md., and Fairfax County, Va., responded to live fires within this facility. NIST researchers and their collaborators conducted more than 60 controlled fire experiments to determine the relative effects of crew size, the arrival time of the first fire crews, and the “stagger,” or spacing, between the arrivals of successive waves of fire-fighting apparatus.

The United States Fire Administration reported that 403,000 residential structure fires killed close to 3,000 people in 2008—accounting for approximately 84 percent of all fire deaths—and injured about 13,500. Direct costs from these fires were about $8.5 billion. Annually, firefighter deaths have remained steady at around 100, while tens of thousands more are injured.

Researchers from NIST, Worcester Polytechnic Institute, the International Association of Fire Chiefs, the International Association of Fire Fighters, the Commission on Fire Accreditation International-RISK and the Urban Institute participated in the study. The report was funded by the U.S. Department of Homeland Security, Federal Emergency Management Agency’s (FEMA) Assistance to Firefighters Grant Program and released today in Washington, D.C., before the start of the annual Congressional Fire Services Institute meeting that draws top fire safety officials from across the nation.

For more details, see the NIST news announcement “Landmark Residential Fire Study Shows How Crew Sizes and Arrival Times Influence Saving Lives and Property,” from April 28, 2010 at www.nist.gov/bfrl/fire_research/residential-fire-report_042810.cfm. The Report on Residential Fireground Field Experiments, NIST Technical Note 1661, can be downloaded from www.nist.gov/manuscript-publication-search.cfm?pub_id=904607.

Media Contact: Evelyn Brown, evelyn.brown@nist.gov, 301-975-5661

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Two NIST Researchers Nominated for Service to America Medals

Two researchers at the National Institute of Standards and Technology (NIST) have been nominated for prestigious Service to America medals. The finalists are contenders for two of the eight awards, including Federal Employee of the Year, that will be presented on Sept. 15, 2010, at a ceremony in Washington, D.C.

Physicist Till Rosenband has been nominated for the “Call to Service Medal,” which recognizes professional achievements by young, up-and-coming federal employees. Rosenband was nominated for inventing the world’s most precise timekeeping device, an entirely new type of atomic clock based on quantum computing research. (See “NIST ‘Quantum Logic Clock’ Rivals Mercury Ion as World’s Most Accurate Clock,” NIST Tech Beat, March 18, 2008, at http://www.nist.gov/public_affairs/techbeat/tb2008_0318.htm#clock.) Current versions of the experimental clock are in principle 30 times better than the current atomic clock standard for time and would gain or lose only one second in three billion years.

Physicist Joshua Bienfang has been nominated for the Science and Environment Medal, which recognizes a significant contribution to the nation by a federal employee in science and environment research (including biomedicine, economics, energy, information technology, meteorology, resource conservation and space). Bienfang has used quantum physics and telecommunications technologies to demonstrate encryption services at record speeds in a system whose security is based on the properties of quantum objects, in this case, photons. (See “System Sets Speed Record for Quantum Encryption,” NIST Tech Beat, May 7, 2004, at http://www.nist.gov/public_affairs/techbeat/tb2004_0507.htm.)

The Service to America Medals are presented annually by the nonprofit, nonpartisan Partnership for Public Service to celebrate excellence in our federal civil service. See the complete list of 2010 Service to America Medal finalists at http://servicetoamericamedals.org/SAM/finalists10/.

Media Contact: Michael Baum, baum@nist.gov, 301-975-2763

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NIST Physicist Named Outstanding Young Scientist of 2010 by Maryland Academy of Sciences

Ian Spielman, a physicist at the Joint Quantum Institute (JQI), a collaboration of the National Institute of Standards and Technology (NIST) and the University of Maryland at College Park, has been selected by the Maryland Academy of Sciences as the Outstanding Young Scientist for 2010. The award will be presented at a ceremony that will be held on May 20, 2010, at the Maryland Science Center in Baltimore.

By shining laser light and applying an external magnetic field with a gradient on a gas of neutral atoms in an ultracold state of matter known as a Bose-Einstein condensate, Spielman and his colleagues have synthesized an environment in which the neutral atoms act as if they were charged particles swirling in a uniform magnetic field (see “JQI Researchers Create ’Synthetic Magnetic Fields’ for Neutral Atoms,” at www.nist.gov/physlab/div842/synthetic_121509.cfm).

Providing new insights into the quantum physics of charged particles in magnetic fields, this work promises to shed light on complex quantum phenomena involving charged particles and potentially enable an exotic new form of quantum computing that would rely on charged particles dancing on a surface (see “Cross-Dressing Rubidium May Reveal Clues for Exotic Computing,” at www.nist.gov/physlab/div842/rubidiu_022409.cfm).

A page on the award can be found at www.mdsci.org/programs/OYE_OYS/CurrentWinners.html

Media Contact: Michael Baum, baum@nist.gov, 301-975-2763

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