Nuclear and atomic data for applications
The Agency's activities in the physical and chemical sciences cover nuclear and atomic data, which are basic inputs for all nuclear applications; nuclear instrumentation, the tools for the measurement and quantification of nuclear radiation; the utilization of research reactors and low energy accelerators for a variety of applications; and radiochemical applications relevant to radioisotope production and use in nuclear medicine, industry and ultratrace analysis. During 1996, the availability of nuclear and atomic data libraries for users worldwide was enhanced through the introduction of a World Wide Web interface. Newly initiated CRPs in the area of nuclear instrumentation are concerned with the development of improved software for gamma spectrometry and computer assisted troubleshooting of instrument faults. Application of the X ray fluorescence (XRF) technique was expanded in several areas and efforts continued to be directed towards better utilization of existing research reactor and low energy accelerator facilities in Member States. The main focus of radiochemical applications was on the development of new and novel radiopharmaceuticals for the diagnosis of neurological disorders in patients and to further explore the field of therapeutic radiopharmaceuticals. The Agency's Analytical Quality Control Service (AQCS) continued to try and improve the accuracy of analytical and radiometric measurements in Member State laboratories to ensure the international acceptance of such measurements.
In response to rapid developments in electronic computer networks, Internet access to the nuclear and atomic databases of the Agency was improved through the introduction of a World Wide Web interface. The available databases provide the most accurate and up-to-date nuclear physics data files that are needed for all nuclear technology applications. The use of on-line data retrievals again increased by about 50%, benefiting several hundred end-users in a growing number of Member States. In addition to the extended on-line services, conventional services continued to institutes in more than 80 Member States.
In response to the needs of the International Thermonuclear Experimental Reactor in its Engineering Design Activities, a validated and tested fusion evaluated nuclear data library (FENDL-1) was officially released. An improved database for particle-impact-induced erosion of fusion reactor materials was also completed.
Co-ordination of the International Data Network of Nuclear Data Centres resulted in the release of four major databases, two of them of interest applicable in materials analysis by gamma spectroscopy. A neutron metrology file was released for use in reactor neutron dosimetry.
A CRP was begun on photonuclear data. The aim is to produce a handbook and data library for improved dose rate predictions on photon radiotherapy using medical electron accelerators.
A CRP was initiated on specialized software utilities for gamma ray spectrometry. This research will help Member States improve their ability to analyse trace quantities of materials by means of computer assisted nuclide identification, quality assurance provisions and 'loss free' counting and air monitoring.
The Agency's Laboratories at Seibersdorf continued to help many Member States to improve nuclear analytical techniques and upgrade infrastructures for nuclear instrument repair and maintenance by providing technical advice, documentation, troubleshooting tools and kits. Upon request, the Laboratory also designed and built special instruments and training kits, such as a portable dosimeter, a portable XRF unit power supply, a UNOLAB timing single channel analyser, a counting instrument and a digital temperature controller for entomology research.
The Laboratories also promoted the use of the XRF technique for materials analysis by improving the steps in this analytical method, including sample preparation, measurement and data processing. Optimum sample preparation procedures for X ray microfluorescence were developed for geological, biological and environmental materials. A new total reflection XRF module was constructed and put into operation implemented for routine analysis. Several portable XRF units were developed to extend the applicability range of XRF for in situ measurements, including one based on a thermoelectrically cooled silicon detector.
An e-mail distribution service was established in Africa with the assistance of the Agency's Laboratories to facilitate regional co-operation in nuclear instrument maintenance. The resulting improved links between Member States, the Agency and suppliers will speed up the provision of spare parts and technical documentation. Since infrastructure for training has improved considerably in the past year, the Laboratories can now offer unique, practically oriented and specialized training programmes for Fellows from developing Member States in the repair, servicing and design of nuclear instruments, computer interfacing, power conditioning, and methodology and applications of various XRF techniques.
At a seminar on the enhancement of research reactor utilization, held in Mumbai, India, in March, the role of research reactors in providing services to Member States was highlighted. Some of the topics discussed were: radioisotope production; industrial irradiation; neutron activation analysis; neutron beam applications; reactor refurbishment; and reactor operations. The objectives of the seminar were to provide ideas for the better utilization of research reactors and foster contacts for greater international co-operation.
The first Research Co-ordination meeting for a CRP on the analysis of research reactor transients was held in Vienna. The goal of the CRP is to develop updated codes suitable for the small computers available at research reactor centres, as well as expertise, procedures and documentation for carrying out reactor transient calculations.
An agreement was signed between the Agency and the Rudjer Boškovic Institute in Zagreb, Croatia, for utilization of the Agency beamline on the accelerator at that institute. This agreement extends the nuclear analytical capabilities of the Agency to incorporate the field of accelerator ion beam applications. The Agency beamline was utilized for the analysis of soil and plant samples, glass fibres, air filters and algae samples, which are candidate reference materials.
Technetium-99m (99Tcm) continues to dominate diagnostic nuclear medicine and efforts continued to support the development of 99Tcm radiopharmaceuticals for new applications, with the focus on early detection of various diseases. Receptor binding molecules labelled with 99Tcm, such as peptides, are of particular interest in view of their potential role in the diagnosis of a variety of disorders, and possible therapeutic treatment by replacing 99Tcm with chemically analogous, beta emitting nuclides such as rhenium-188/186.
A CRP on 99Tcm labelled peptides for imaging peripheral receptors, particularly analogues of the neuropeptide somatostatin, was initiated. Many neuroendocrine tumours are rich in somatostatin receptors. 99Tcm labelled somatostatin analogues would be useful in imaging such tumours. This CRP focuses on 99Tcm labelling of appropriately derivatized analogues of somatostatin and the development of radiochemical and biological quality control methods for assessing their suitability for imaging. The first Research Co-ordination meeting was held in Portugal.
Another CRP on the development of agents for imaging central neural system (CNS) receptors based on 99Tcm was also initiated. The development of 99Tcm CNS receptor specific agents is expected to have a significant impact on the diagnosis and management of patients suffering from neurological disorders such as Parkinson's disease, Alzheimer's disease and schizophrenia, owing to the widespread availability of 99Tcm. The CRP will focus in the first phase on the synthesis of neutral 99Tcm complexes that are able to cross cell membranes and can be derivatized to attach CNS receptor binding moieties. In the second phase, 99Tcm labelling of such chelate moieties and their evaluation using in vitro and in vivo models will be carried out.
Interest in targeted radiotherapy using radiopharmaceuticals has been growing in view of its potential advantages over conventional radiotherapy. At the second Research Co-ordination meeting, held in Brazil, for a CRP on optimizing the production of novel therapeutic radionuclides, promising results were reported for the palliation of metastatic bone pain using samarium-153 diphosphonates. The recent introduction of monoclonal antibodies and peptides for the specific targeting of radionuclides in vivo has highlighted the possible use of such biomolecules for targeted radiotherapy. An Advisory Group meeting on labelled biomolecules for such radiotherapy was held in the Netherlands to suggest future directions for research in this area. The meeting reviewed the present status of targeted radiotherapy and identified two prospective areas for further research, one on small molecules such as rhenium-186(V) DMSA and the other on monoclonal antibodies and peptides labelled with yttrium-90 and samarium-153.
Fluorine-18 and iodine-123 are two cyclotron produced radioisotopes which can be used to label natural substrates, biomolecules and drugs for use as biochemical tracers in tomographic imaging. These tracers show great promise in the study of molecular medicine in vivo. A new CRP was initiated which focuses on the optimization of synthetic procedures, automation of production, development of quality control methods and biological assays for iodine-123 and fluorine-18 labelled peptides.
The Agency's AQCS, through its laboratories at Seibersdorf, initiates and supports improvements in the accuracy of analytical chemistry and radiometric measurements and their traceability to basic standards by, among other things, distributing reference materials. In order to harmonize quality requirements for the production of Agency reference materials and for certification procedures with international standards, the AQCS formulated good analytical practices for the certification of such materials. Work began on the certification of two proposed algae reference materials (as per ISO 'Guide 35') that will serve as models for the certification of future materials.
Trace element analysis of objects, especially ceramic materials, recovered in archaeological excavations are very useful for establishing chronologies. Of the various techniques available with sufficient sensitivity and precision to provide useful data in archaeological research, instrumental neutron activation analysis (INAA) is one of the most effective. In a new CRP archaeologists and experts in INAA from a number of Latin American countries will be brought together to apply INAA for archaeological investigations with the active collaboration of the Smithsonian Institution in the USA.
Nuclear analytical techniques (NATs) are useful in the precious and rare metal and mining industries for: determining the chemical composition of major, minor and trace elements; yield optimization of the separation process; quality control programmes; and the minimization of waste and pollution. A CRP on the development of NATs for precious and rare metals in mineral concentrates was initiated. This is expected to help realize the enormous potential of these techniques to improve raw material utilization in ore processing and lead to savings in energy and materials in these processes.