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Dosimetry Group
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Welcome
The Dosimetry Group advances the measurement of quantities important in the radiological sciences through programs in the dosimetry of x-rays, gamma-rays, electrons, and other charged particles. Its mission is to develop, maintain, and disseminate the national measurement standards for these radiations, and to engage in research on radiation interactions and effects to meet requirements for new standards and to address the needs of industry, medicine, and government. These standards are disseminated both directly to the customer and through networks of secondary calibration laboratories by means of calibrations and proficiency testing services provided to maintain measurement-quality assurance traceability. We maintain the national standards for the gray, the Système International (SI) unit for radiation dosimetry, and development, maintain and disseminate high-quality data on fundamental radiation interactions. These are used extensively in radiation transport calculations and simulations, using algorithms and codes often developed by our staff, to solve a wide range of problems in radiation science and applications. Our work on homeland-security applications continued, while significant progress was made in our more traditional radiation-dosimetry programs. The development of performance criteria for x-ray and gamma-ray screening systems used in homeland-security applications was advanced through official working groups writing ANSI standards (imaging performance of small-particle checkpoint screening systems, CT checked-baggage screening systems, vehicle/cargo inspection systems and of personnel body-scanning systems. Significant progress has been made in a number of our measurement standards and calibration services. Our research in improved water calorimetry to realize absorbed dose continues to move forward, and our clinical electron accelerator has been used extensively in the development of a second-generation water calorimeter to serve as a national standard for accelerator-produced high-energy x-ray beams used in cancer therapy. We work closely with the networks of secondary calibration laboratories traceable to us and continue to expend our capabilities in a number or measurement areas. Our staff continues to make important contributions to the work of national and international standards and of scientific organizations, and we are central to measurement-quality assurance of dosimetry in the many application areas of ionizing radiation. Programs/Projects
High-Dose Dosimetry Uncertainty Tables—The high-dose dosimetry program supports radiation-processing applications by assuring that the absorbed dose to the product, often prescribed or limited by regulatory agencies, is traceable to … High-Dose Dosimetry—The activities described here support the application of high-dose, high-energy ionizing radiation for a variety of industrial processes. Radiation-induced materials modifications improve the … Dosimetry Standardization for Radiobiology—A program for the development of dosimetry standards for radiobiology was launched through a highly successful workshop. The NIAID/NCI/NIST-sponsored workshop on Radiation Dosimetry … X-Ray Standards—A new free-air ionization chamber has been built to eventually replace the Wyckoff-Attix chamber, which has been used at NIST as a primary x-ray standard for more than fifty years. Spectrometry of X-Ray Beams Used for Calibrations—Spectrometry measurements in the x-ray calibration ranges have been undertaken using a high-resolution HPGe detector both in the direct beam and at 90 % using a Compton-scatter spectrometer. Theoretical Dosimetry and Radiation-Transport Calculations—The radiation transport methods pioneered and developed at NIST to calculate the penetration of electrons and photons in matter are used in most of the major Monte Carlo simulation codes today. Advancing Alanine Dosimetry for Small Radiosurgery Fields—Research is underway to expand the current range (20 Gy to 200 kGy) of alanine dosimetry to include therapy level dosimetry (as low as 1 Gy) for small-field radiation treatment applications (e.g., … International Comparisons for Air Kerma and Absorbed Dose to Water from Gamma-ray Beams—A bilateral comparison was conducted between NIST and the International Atomic Energy Agency (IAEA) to support international efforts for harmonizing radiation protection measurements around the … Standard Reference Data on Radiation Interactions—NIST has nearly five decades of experience in the development of critically evaluated, comprehensive databases of cross-section information for ionizing photons (x and gamma rays), electrons, and … Calibration of Low-Energy Photon Brachytherapy Sources—Small radioactive "seed" sources used in prostate brachytherapy, containing the radionuclide 103Pd, 125I, or 131Cs, are calibrated in terms of … Evaluation of Uncertainty in Brachytherapy Dosimetry—NIST is participating in Task Group # 138 (TG-138) of the American Association of Physicists in Medicine (AAPM), AAPM Recommendations on Assessing Uncertainty of the Brachytherapy Clinical Dose … The Development of New Reference Standards for Digital Mammography—With the introduction and Food and Drug Administration (FDA) approval of mammography units using a tungsten (W) anode with either a silver (Ag) or rhodium (Rh) filter, there are new concerns about … Calibrations of a Miniature X-ray Source Used for Electronic Brachytherapy—A new laboratory dedicated to establishing a national primary air-kerma rate standard for Xoft's AXXENT™ miniature x-ray source has been fabricated. The Xoft source was … Applications of NIST Alanine/EPR Dosimetry to the Irradiation of Blood and Blood Products—At present, gamma irradiation of blood products is the only procedure known to prevent transfusion-associated graft-versus-host disease (TA-GVHD). Comparison of Co60 Absorbed Dose for High-Dose Dosimetry—NIST participated in a recent international comparison of standards for absorbed dose to water for 60Co gamma radiation at radiation-processing dose levels organized by the Bureau International des … A Study of the Irradiation-Temperature Coefficient for Alanine Film and Pellet Dosimeters at Elevated Temperature—Correcting the response of a dosimeter for the average temperature during irradiation processing improves the accuracy of the dose measurement. Dose/Dose-Rate Effects in Alanine Dosimetry—Check standards are used by the NIST Ionizing Radiation Division to monitor the performance of the alanine dosimetry system that is central to its high-dose transfer dosimetry service. X-ray Security-Screening Standards for Homeland Security—With support from the Department of Homeland Security (DHS), the Radiation Interactions and Dosimetry Group facilitates the development and maintains technical-performance standards for five … Air-Kerma Measurements in High Energy X-ray Beams—In the past few years there has been an increase in the deployment of x-ray screening systems at security checkpoints around the U.S. These systems are designed to detect potential … NIST Work in Support of the Navy Dosimetry Program—During the last 2 years, NIST has helped the U.S. Navy transition to a new dosimetry system by providing dosimeter irradiations in 137Cs gamma-ray beams. Advances in Water Calorimetry—The NIST water calorimetry effort has been directed toward accurate modeling and detailed measurement of time-varying phenomena within the calorimeter vessel – due principally to heat … Accelerator Facilities—The Radiation and Biomolecular Physics Division's accelerator facilities continue to support a broad range of research efforts in the areas of industrial and medical dosimetry, homeland … Applications of Diagnostic X-ray Spectrometers—The Dosimetry Group designs, fabricates, and calibrates bent-crystal optics and diagnostic spectrometers for customers around the world. Calibrations of Radiation Measuring Instruments in Cs-137 and Co-60 Gamma-ray Beams—The Dosimetry Group maintains and disseminates the national measurement standards for air-kerma (exposure) from 137Cs and 60Co gamma-ray beams and for absorbed dose to water from 60Co … Absorbed-Dose Measurements to Support Biologics Research—The Dosimetry Group have been working with Maryland-based biotech firm Sanaria Inc. that is planning to manufacture a new vaccine against malaria. Advanced X-ray Systems for the Detection of Special Nuclear Materials—The Dosimetry Group provides support to the Domestic Nuclear Detection Office (DNDO) of the Department of Homeland Security (DHS) for their advanced non-intrusive inspection (NII) initiatives. Our … NIST Calibrations of a Miniature X-Ray Source Used for Electronic Brachytherapy— A new laboratory dedicated to establishing a national primary air-kerma rate standard for Xoft's AXXENT™ miniature x-ray source has been fabricated |
 Contact
Michael G. Mitch, Group Leader 301-975-5491 Phone 100 Bureau Drive, M/S 8460 Dosimetry Group Staff Directory
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