ABSTRACT
Cross section data for formation of the medically important radionuclide (61)Cu (T½=3.33h) in proton and deuteron induced reactions on enriched (64)Zn and in (3)He- and α-particle induced reactions on (59)Co were analyzed by using the nuclear model calculational codes, EMPIRE and TALYS. A well-defined statistical procedure was then employed to derive the recommended excitation functions, and therefrom to obtain integral yields. A comparison of major production routes of (61)Cu was done.
Subject(s)
Cobalt Isotopes/chemistry , Copper Radioisotopes/chemistry , Deuterium/chemistry , Helium/chemistry , Isotope Labeling/methods , Models, Chemical , Zinc Isotopes/chemistry , Cobalt Isotopes/radiation effects , Computer Simulation , Copper Radioisotopes/isolation & purification , Copper Radioisotopes/radiation effects , Deuterium/radiation effects , Helium/radiation effects , Isotopes/chemistry , Isotopes/radiation effects , Protons , Radiation Dosage , Zinc Isotopes/radiation effectsABSTRACT
This paper describes the utility of electrodeposition method to prepare (57)Co point sources. A description of the electrolytic cell, the process of (57)Co electrodeposition, encapsulation and quality control of the sealed (57)Co sources is presented. Sources containing ~3.7-4.81 MBq (0.10-0.13 mCi) of (57)Co were prepared, encapsulated in miniature titanium capsules and subjected to quality control tests to ensure compliance with regulatory requirements. The encapsulated (57)Co sources prepared by the reported procedure were found to be effective in routine performance evaluation of nuclear medicine instruments.
Subject(s)
Cobalt Isotopes/chemistry , Diagnostic Imaging/instrumentation , Nuclear Medicine/instrumentation , Diagnostic Imaging/standards , Quality ControlABSTRACT
The Brazilian Institute of Radiation Protection and Dosimetry (IRD/CNEN) carried out quality assurance regulatory audits in Brazilian radiotherapy facilities from 1995 to 2007. In this work, the set of data collected from 195 radiotherapy facilities that use high-energy photon beams are analyzed. They include results from audits in linear electron accelerators and/or Co-60 units. The inspectors of IRD/CNEN performed the dosimetry of high-energy radiotherapy photon beams according to the IAEA dosimetry protocols TRS 277 and TRS 398, and the values of measurements were compared to stated values. Other aspects of radiological protection were checked during on-site audits such as calibration certification of clinical dosimeters and portable monitors, existence and use of check source, use of barometer and thermometer, individual dose registry and training of staff. It was verified that no check source was available in 38% of the visited facilities; the training of personnel was not adequate in 9% of the facilities and the registry of accumulated individual doses was not being done in 6% of the facilities. Measurements of absorbed dose have indicated deviations in the range ± 3% for 67.6% of the cobalt-60 units and 79.6% of medical linear accelerators; 18.5% of Co-60 irradiators and 9.6% of linear accelerators presented deviations in the range 3% < δ ≤ 5%. Finally, 13.9% of Co-60 facilities and 10.8% of linear accelerator facilities presented dosimetry deviations above 5%. The effort in dosimetric quality control performed by IRD/CNEN audits has yielded positive changes that make radiation treatment facilities more reliable.
Subject(s)
Radiometry/methods , Radiotherapy, High-Energy/methods , Brazil , Calibration , Cobalt Isotopes/chemistry , Humans , Particle Accelerators , Quality Control , Radiation Oncology/standards , Radiation Protection/methods , Radiotherapy Dosage , Radiotherapy, High-Energy/standards , Safety , ThermometersABSTRACT
To demonstrate the potential of nuclear magnetic resonance (NMR) spectroscopy for investigating detailed structural properties in ferromagnetic materials, three different particle sized cobalt (Co) powders have been ball milled for 24h are accurately characterised by internal-field (59)Co NMR. The (59)Co NMR spectra show distinct resonance bands corresponding to the different Co sites, face-centred-cubic (fcc), hexagonal-close-packed (hcp) and stacking faults (sfs), in Co metal powders. The hcp+fcc-->hcp phase transition encouraged by ball-milling was observed and quantitative values for each Co environment were obtained.
Subject(s)
Cobalt Isotopes/analysis , Cobalt Isotopes/chemistry , Magnetic Resonance Spectroscopy/methods , Manufactured Materials/analysis , Models, Chemical , Models, Molecular , Computer Simulation , Feasibility Studies , Materials Testing/methods , Molecular Conformation , Particle SizeABSTRACT
59Co triple-quantum (3Q) MAS and single-pulse MAS NMR spectra of K3Co(CN)6 have been obtained at 14.1 T and used in a comparison of these methods for determination of small chemical shift anisotropies for spin I = 7/2 nuclei. From the 3QMAS NMR spectrum a spinning sideband manifold in the isotropic dimension with high resolution is reconstructed from the intensities of all spinning sidebands in the 3QMAS spectrum. The chemical shift anisotropy (CSA) parameters determined from this spectrum are compared with those obtained from MAS NMR spectra of (i) the complete manifold of spinning sidebands for the central and satellite transitions and of (ii) the second-order quadrupolar lineshapes for the centerband and spinning sidebands from the central transition. A good agreement between the three data sets, all of high precision, is obtained for the shift anisotropy (delta(sigma) = delta(iso) - delta(zz)) whereas minor deviations are observed for the CSA asymmetry parameter (eta(sigma)). The temperature dependence of the isotropic 59Co chemical shift has been studied over a temperature range from -28 to +76 degrees C. A linear and positive temperature dependence of 0.97 ppm/degree C is observed.
