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Title: Innovative methodology for intercomparison of radionuclide calibrators using short half-life in situ prepared radioactive sources

Purpose: An original radionuclide calibrator method for activity determination is presented. The method could be used for intercomparison surveys for short half-life radioactive sources used in Nuclear Medicine, such as{sup 99m}Tc or most positron emission tomography radiopharmaceuticals. Methods: By evaluation of the resulting net optical density (netOD) using a standardized scanning method of irradiated Gafchromic XRQA2 film, a comparison of the netOD measurement with a previously determined calibration curve can be made and the difference between the tested radionuclide calibrator and a radionuclide calibrator used as reference device can be calculated. To estimate the total expected measurement uncertainties, a careful analysis of the methodology, for the case of{sup 99m}Tc, was performed: reproducibility determination, scanning conditions, and possible fadeout effects. Since every factor of the activity measurement procedure can influence the final result, the method also evaluates correct syringe positioning inside the radionuclide calibrator. Results: As an alternative to using a calibrated source sent to the surveyed site, which requires a relatively long half-life of the nuclide, or sending a portable calibrated radionuclide calibrator, the proposed method uses a source preparedin situ. An indirect activity determination is achieved by the irradiation of a radiochromic film using {sup 99m}Tc under strictly controlledmore » conditions, and cumulated activity calculation from the initial activity and total irradiation time. The irradiated Gafchromic film and the irradiator, without the source, can then be sent to a National Metrology Institute for evaluation of the results. Conclusions: The methodology described in this paper showed to have a good potential for accurate (3%) radionuclide calibrators intercomparison studies for{sup 99m}Tc between Nuclear Medicine centers without source transfer and can easily be adapted to other short half-life radionuclides.« less
Authors:
 [1] ;  [2] ;  [3] ;  [3] ;  [3]
  1. Centro de Investigação do Instituto Português de Oncologia do Porto Francisco Gentil, EPE, Porto, Portugal and Departamento de Física e Astronomia, Faculdade de Ciências da Universidade do Porto (Portugal)
  2. Centro de Investigação do Instituto Português de Oncologia do Porto Francisco Gentil, EPE, Porto (Portugal)
  3. (Portugal)
Publication Date:
OSTI Identifier:
22412473
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 41; Journal Issue: 7; Other Information: (c) 2014 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
07 ISOTOPES AND RADIATION SOURCES; 60 APPLIED LIFE SCIENCES; COMPARATIVE EVALUATIONS; NUCLEAR MEDICINE; POSITRON COMPUTED TOMOGRAPHY; RADIATION SOURCES; RADIOPHARMACEUTICALS; TECHNETIUM 99