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  • 61.12.Ld  (1)
  • 99mTc-sodium pertechnetate  (1)
  • Effective doses  (1)
  • 1
    ISSN: 1090-6487
    Keywords: 75.70.Pa ; 72.60.1g ; 61.12.Ld
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The evolution of the structural and magnetic properties of the CMR (colossal-magnetoresistance) compound La0.35Pr0.35Ca0.30MnO3 as the temperature changes from 10 to 293 K is investigated by means of neutron diffraction. It is shown that the changes in the transport and magnetic properties are directly related with the rearrangement of the atomic structure. A phase transition to the metallic state occurs together with simultaneous ferromagnetic ordering of the manganese moments and is accompanied by a jump in volume. The static distortions of the oxygen octahedra which are observed to occur prior to the magnetic phase transition and which are practically absent at room temperature and in the FM phase attest to the orbital ordering of oxygen atoms on the bonds, with freezing-in of the Jahn-Teller modes.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1084
    Keywords: Key words: Diagnostic radiology (Germany) ; Annual frequency of examinations ; Effective doses ; Collective doses ; Radiation risk for patients
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The exposure of the German population to man-made radiation results mainly from diagnostic X-ray and nuclear medical examinations. Data are presented about the annual frequency and the average dose of the various examination types for West Germany in the years 1990–1992. According to these data a yearly average of approximately 1550 diagnostic examinations using ionizing radiation were performed per 1000 inhabitants resulting in an annual per caput effective dose of 1.9 mSv. Despite the frequent use of alternative examination techniques, such as sonography, nuclear magnetic resonance and endoscopy, the frequency of X-ray and nuclear medical examinations is still increasing. If collective risk assessments are done using the per caput effective dose, at least the age distribution of the patients must be considered. This leads to a “risk-modifying factor“ of 0.6–0.7 for patients to be applied to the ICRP risk coefficient of 5 % per Sv valid for the general population. However, radiation risk must always be viewed in context with disease- and therapy-related risks and balanced against the benefit of the diagnostic examination, which should always exceed the risk for a well-indicated procedure.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1619-7089
    Keywords: Radionuclide impurities ; Dose to the patient ; 99mTc-sodium pertechnetate ; Fission product 99Mo ; European Pharmacopoeia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Radionuclide impurities of radiopharmaceuticals do not provide any diagnostic information, but contribute to the radiation dose to the patient. For 99mTc, even small amounts of long lived radionuclide impurities may contribute significantly to the dose from 99mTc itself. In this preliminary study, estimates have been made for the radiation dose to specific organs and for the effective dose equivalent from impurities in 99mTc-sodium pertechnetate prepared from fission product 99Mo. In addition to 99Mo, 131I, 103Ru, 89Sr and 90Sr at maximum permissible levels as stipulated in the European Pharmacopoeia, 110mAg and 239Pu were taken as representative nuclides for beta-gamma emitters and alpha emitters. Using all of these radionuclides at such maximum permissible levels of impurity as stated in the European Pharmacopoeia, the total contribution from the impurities to the effective dose equivalent is approximately 30% of the effective dose equivalent from 99mTc-pertechnetate. In terms of specific organs, the liver and kidneys can receive doses of 3–4 times and 1–3 times the dose from 99mTc-pertechnetate itself. Although these are worst case calculations, a consistent approach should be reconsidered to limit the additional effective dose equivalent from impurities to e.g. 10% of the effective dose equivalent from 99mTc itself.
    Type of Medium: Electronic Resource
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