No abstract available

No abstract available

[en] In the scope of medical radiological exposures and according to European recommendations and national legal requirements [14], the maximum responsible for an installation must assure the establishment of local dose levels for each type of radiological examination and also assure that they are available for the doctor who prescribes the examination. In the absence of national reference dose levels, the so called Local Diagnostic Reference Levels (L.D.R.L.) should be in agreement with the European Diagnostic Reference Levels published for the different types of medical exposures. The aim of this work was to establish a protocol of measurement for each type of more frequent examination, namely in conventional radiology, in CT and in mammography performed in our hospital. For each kind of examination the recommended dose descriptor was adopted and directly measured or derived from basic charge measurements. The patient sample corresponded in each case to at least a minimum of 10 standard-sized patients, as recommended, in order to obtain averages that constitute for each type of radiological examination the L.D.R.L. that could be compared with the European D.R.L.. The results obtained are in the large majority of the situations below the corresponding D.R.L.. Nevertheless we have identified some situations that deserve more attention.In conventional radiology all L.D.R.L. are below the reference levels. However we have detected some skull post anterior (skull P.A.) exposures where entrance skin doses exceeded the standard value. This may be due to equipment age problems but, as always, improvement of staff education will contribute to better practices and we hope that this work can contribute to this objective. In CT the L.D.R.L. that corresponds to single slice scan meet the standards whereas complete examinations described by dose length product (D.L.P.) values show a larger variation and also some situations where the reference level is exceeded. It is possible that doctors are requiring too large ranges for complete examinations. Mammography was perhaps the area that deserved more evident alert. The results clearly showed that the majority of entrance surface dose (E.S.D.) values determined in mammography exceeded the recommended reference level. In fact the mammography unit used to establish the dose measurement protocol was dismounted soon after the end of this work. A new digital mammography unit is now installed. We hope that new L.D.R.L. that will soon be obtained can accomplish the dose requirements. The results obtained so far may not be the best ones but it was the beginning of a very important way towards better practices, more information to staff and patients and improved quality assurance of clinical radiological examinations. As a last conclusion we would like to state that this was a pioneer work in Portugal. We hope that this may lead the way to further developments. (authors)

[en] For these last years, the management of radioactive wastes took up the international forefront by coming within the scope of the nuclear energy becoming. The reversibility of nuclear wastes deep storage is discussed here. A second point about the measurement of radiation doses in diagnosis using radioisotopes or ionizing radiations is studied because of the last radiation protection directives through the practices and the detectors. The last point gives the radioactive releases from the PWR type reactors during the period 1995-1997. 172 reactors and twelve countries have been itemized to bring this information. (N.C.)

[en] In the context of optimization of radiological exposures, the European Directive 97/43/Euratom refers to the concept of diagnostic reference levels (DRL). These levels are expected not to be exceeded for standard procedures when good and normal practice regarding diagnostic and technical performance is applied. According to national legal requirements, the maximum responsible for a radiological installation must assure that the radiological exposures are in agreement with accepted dose reference levels. The dose information of each type of examination should be available to the doctor who prescribes it and also to the patient. A measuring protocol has been established in terms of the most convenient dose indicators for each type of the more common examinations carried out in the Imaging Department of the Instituto Portugues de Oncologia de Coimbra (IPOC-FG, E.P.E.). The aim of this work is to compare the dose reference levels locally determined with the European DRLs in conventional radiology, computed tomography and mammography. Also, the relevant information to be given to the patient is discussed and a general model for that information is proposed. DRLs are expressed either in terms of entrance surface dose (ESD), for conventional radiology and mammography, or in terms of computed tomography dose index (CTDI_w) or dose length product (DLP) for CT examinations. This dose information and the exposure parameters for each type of examination are used as input values to the code PCXMC, version 1.5.2., in order to assess patient organ doses and effective dose values in conventional radiology. In the same way, the program CTDosimetry is used in computed tomography. The Average Glandular Dose (AGD) is determined in mammography. In order to give to the patient and also to the doctor who prescribes the examination readily accessible dose information, the concept of BERT (Background Equivalent Radiation Time) has been used. The average value of effective dose for each type of radiological exposure was converted in time of natural background radiation having 1 mSv/year as a reference value. Also the estimated risk associated to each type of examination was included in the patient dose information form. The estimated risk was obtained using the nominal probability coefficient for stochastic effects of 7.3% per Sv. An example of the patient dose information form is presented

No abstract available

[en] In order to put into practice the principle of optimization of the radiation protection for the patient in radiodiagnostics, it would be interesting to have an indicator of risk which is better adapted than the effective dose. This last was defined in the publication 60 of the ICRP to reflect the whole body radiological risk for a general reference population, which gathers people of the two sexes and all ages. However, the exposure of the patient in radiodiagnostic is characterized by a partial exposure of the body. Moreover, the frequency of the examinations in radiodiagnostic depends on sex (mammography) and age (examination of scoliosis versus interventional radiology) of the exposed individuals. The objective of this work is to propose sex and age specific risk coefficients of exposure-induced fatal cancer. (author)

[en] Highlights: • Climate change impacts on extreme precipitations and river runoff. • Increase of extreme river discharges may lead to higher salinity drops in estuarine areas. • Effect of salinity drops on the mortality of bivalves near river mouths. • Bivalves' mortality increases when extreme river runoff and neap tides match. • The physiography of the estuary is crucial to determine the death rate. The mortality of infaunal bivalves (Venerupis corrugata, Cerastoderma edule, Ruditapes decussatus and Ruditapes philippinarum) due to a drop in salinity caused by extreme precipitation events in estuarine areas has been analyzed within a context of climate change. The Rías Baixas (NW Iberian Peninsula) were selected as a representative area of the estuarine environments where bivalve gathering is performed. Bivalve mortality under extreme precipitation events was analyzed both for historical (1990–2019) and future (2070–2099) periods. Precipitation data were retrieved from the Coordinated Regional Climate Downscaling Experiment (CORDEX) project under the Representative Concentration Pathway (RCP) 8.5 scenario and were converted into river discharges using the HEC-HMS hydrological model. The calculated river discharges were introduced into the Delft3D hydrodynamic model and simulations were performed in order to calculate transport conditions in the Rías Baixas. Salinity data were analyzed to estimate the mortality of the species due to salinity drops. In general, future conditions of moderate and severe mortality may be worse than historically observed, being more intense and covering larger areas. This is mainly observed under neap tides due to less dilution of freshwater plumes when compared with spring tides. Although all the Rías Baixas may be potentially affected, the impact will differ for each ria, being Arousa, where the highest discharges occur, the most affected. The differences among rias, especially those with a similar discharge pattern as Pontevedra and Vigo, suggest that bathymetric features also play a key role in the extent of the area affected by mortality.

[en] Highlights: • Influence of climate change on future offshore wind power in the Caribbean. • Future projections by means of an ensemble of RCM from the CORDEX under the RCP8.5 • Wind increases in most (only in southeastern coast) of Caribbean in wet (dry) season. • Wind increase in the wet season associated to changes in the extension of the NASH. • Wind increase in dry season due to an increase in land-ocean temperature gradient. -- Abstract: The Caribbean has suitable conditions for a significant wind energy development, which makes a good planning for the future renewable energy mix essential. The impact of climate change on Caribbean wind power has been analyzed by means of an ensemble of CORDEX regional climate models (RCMs) under the RCP8.5 warming scenario. The offshore wind energy resource was classified for the historical period and for the future considering wind energy factors, environmental risk factors and cost factors whose weights were estimated by a Delphi method. Future projections show a maximum annual wind increase, ∼0.4 ms⁻¹ (8%), in most of the Caribbean, except in the Yucatán Basin. This increment occurs mainly during the wet season, ∼0.5 ms⁻¹ (∼10%), associated with changes in the extension of the North Atlantic Subtropical High, which will strengthen the Caribbean low-level jet. Additionally, the moderate wind increase, ∼0.2 ms⁻¹ (∼4%), projected during the dry season is restricted to the southeastern coast and it is associated with an increment in the land-ocean temperature difference (∼1 °C), which will intensify local easterly winds. The low-level jet region was classified as the richest wind energy resource in the Caribbean for the future with a larger extension compared to the historical period.