[en] In September 1987, a radiological accident, involving the stealing and breaching of a Cs-137 medical source, contaminated several people. Prussian Blue was used to enhance the elimination of Cs from de body. The main excretion pathway for Cs is urine. The Prussian Blue acts by binding Cs in the lumen of the gut, increasing the fecal excretion. The efficiency of Prussian Blue have been evaluated through the analysis of the biological half-life for Cs, estimated using urine and feces data. The average percentage reduction of biological half-life was 67% for 3, 6 and 10 g/day of Prussian Blue. (author)

[en] In order to assure that a facility is in compliance with the occupational exposure requirements established by regulatory authorities, the measurements and dose assessments specified in the individual monitoring programme need to be reliable. There are two important questions that shall be addressed here: one is how the licensed facilities can demonstrate to their workers and regulatory bodies compliance with the regulatory limits and the reliability of the results of the individual monitoring programmes; the other concerns the mechanisms used to demonstrate to a facility in another country the reliability of the measurement results of an individual monitoring bioassay programme. The accreditation of the bioassay laboratory, according to ISO/IEC 17025, shall be the basic requirement for obtaining the authorisation granted by the national regulatory authority. For the second question, such confidence can be achieved through International Laboratory Accreditation Cooperation (ILAC). (author)

[en] The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) continuously evaluates the worldwide levels of occupational radiation exposure for two broad categories of sources: natural sources of radiation and man-made sources of radiation. The UNSCEAR evaluation is based on data from the UNSCEAR Global Survey of Occupational Radiation Exposures conducted by formal request to all 192 Member States of the United Nations, supplemented with data from literature. The UNSCEAR evaluations need to provide information relevant for policy and decisions regarding the use and management of radiation. The UNSCEAR questionnaire is designed in order to obtain the basic data to evaluate the level of occupational exposure in each sector and sub-sector of work. Specific additional information is requested for each sector or subsector and category of worker; as well as information to evaluate the reliability of the data. The UNSCEAR questionnaire is in good agreement with currently updated national databases. Since these databases for occupational exposure are the main source of information for UNSCEAR, they need to be regularly updated in order to reflect any change on the level of occupational radiation exposure when new technological developments and modifications to work practices occur. (author)

[en] The Goiania radiological accident involved a large number of individuals who became internally contaminated and/or were externally exposed to a stolen ¹³⁷Cs source. The results of bioassay and cytogenetic monitoring during the emergency phase and the follow-up of the accident are reviewed. An age-weight specific Cs retention model was developed. The effectiveness of Prussian Blue, a drug given to enhance the elimination of Cs from the body, was evaluated. Internal committed absorbed doses were estimated using monitoring data and were compared with results from preliminary dose assessments. A summary of a model for the kinetics of elimination of chromosomal aberrations is also presented. (author)

[en] Prussian blue was used to enhance the elimination of ¹³⁷Cs from 46 individuals contaminated in an accident in Goiania, Brazil, in 1987. PB dosages administered to the victims varied from 1 to 3 g.d^-1 for children and from 3 to 10 g.d^-1 for adolescents and adults. To complement human data in the evaluation of the effectiveness of PB and its relation to age, a 41 day study was conducted using immature (4.7 months old), young adult (2.4 years old) and aged (13.5 years old) male beagle dogs. The mean biological half-times for the Goiania people under PB treatment were 24 ± 3 days, 30 ± 12 days and 25 ± 11 days, for children, adolescents and adults, respectively. The mean reductions of half-times were 43%, 46% and 69%, respectively. The effect of PB was shown to be independent of age and the administered dose. Similar results were found in dogs: the mean biological half-times related to the second component of the equation were 11, 15 and 13 days for the immature, young adult and aged dogs, respectively, indicating a reduction of the clearance half-times of 45%, 45% and 63%. The experiment in dogs has shown that when the PB is administered immediately after caesium intake, its effectiveness is greater in immature than in aged dogs. The percentages of the initial body burden remaining 41 days after caesium intake were 4%, 12% and 8% for the immature, young adult and aged dogs, respectively. This age-related effect correlates with the increased fraction of ¹³⁷Cs eliminated with the fast clearance half-time, and was greater in immature than in aged dogs. (author)

[en] Full text. The principles of radiation protection of the 1990 Recommendations of the International Commission on Radiological Protection was the basis of the International Atomic Energy Agency publication International Basic Safety Standards for Protection Against Ionizing Radiation and for the Safety of Radiation Sources, IAEA Safety Series n. 115, which contains the requirements for the implementation of the Safety Fundamentals. Advice is provided in the International Basic Safety Standards on protection of workers exposed to internally incorporated radionuclides. The Safety Guide on Assessment on Internal Radiation Exposure will give specific guidance on the main principles for monitoring in both routine and emergency situations, including a summary of direct and indirect methods for assessing the body content of a radionuclide, biokinetic models for describing the behaviour of radionuclides in the body and their applications to calculate radiation doses, requirements for record keeping and guidance on quality assurance procedures

[en] Short communication

[en] This paper concerns with the techniques for intakes assessment which depend on the mode and level of intake, the type of energy of the radiation emitted, the biokinetic of the contaminant, and the sensitivity and availability of measurement facilities. In vivo and in vitro techniques are used to quantify internal contaminations

[en] The mining, milling and processing of uranium and thorium bearing minerals may result in radiation doses to workers. The control of occupational exposures from these natural sources of radiation imposes a challenge to regulators and radiation protection advisers. A survey pilot programme, which included six mines in Brazil and a monazite plant, was established, consisting of the collection and analysis of concentrations of uranium, thorium and polonium in urine, faeces and air samples. Results from workers were compared to background data from their families living in the same area and from residents from the population of Rio de Janeiro. Positive exposure results were identified among the coal miners, the niobium miners and the monazite sand workers. Difficulties in the application of internal dosimetry programmes are discussed in relation to the control of NORM workers. (author)

[en] The mining, milling and processing of uranium and thorium bearing minerals may result in radiation doses to workers. A preliminary survey pilot program, that included six mines in Brazil (two coal mines, one niobium mine, one nickel mine, one gold mine and one phosphate mine), was launched in order to determine the need to control the radioactive exposure of the mine-workers. Our survey consisted of the collection and analysis of urine samples, complemented by feces and air samples. The concentrations of uranium, thorium and polonium were measured in these samples and compared to background data from family members of the workers living in the same dwelling and from residents from the general population of Rio de Janeiro. The results from the coal mines indicated that the inhalation of radon progeny may be a source of occupational exposure. The workers from the nickel, gold and phosphate mines that were visited do not require a program to control internal radiological doses. The niobium mine results showed that in some areas of the industry exposure to thorium and uranium might occur. (author)