No abstract available

[en] Abstract only

[en] Therapeutic alpha-emitters are most useful in cases that defy conventional therapeutics, such as residual tumor parts, subclinical tumor recurrency or early metastasis. The favoured nuclide is At-211, mainly due to its chemical reactivity and high specific activity. The half life of 7.2 hrs necessitates the conception of radiotherapeutics with optimal tumor localisation at times of less than 18 hrs

[en] Alpha-contamination concerns radioactive protection and reactor core surveillance. In Rapsodie the nuclides to be identified were ²¹⁰Po and atoms with Z>=92

[en] Elsewhere the authors have discussed new and elaborate techniques for alpha-particle autoradiography using the nuclear track detector CR-39. These techniques are at present being applied in a major study of the microdistribution of alpha-active nuclides in the human lung. Whole lungs with trachea are obtained at autopsy. Case histories representing a wide spectrum of lung burden are sought but that from the general population serves as a baseline from which all abnormal levels may be compared. The lungs are dissected, loaded against CR-39 and stored deep frozen for 3-20 months. Subsequent analysis of the autoradiograph reveals: i) The microdistribution of activity. This includes for example the pattern of deposition around the tracheal bifurcation and across the tracheal wall for both the total activity and separately that due to ²²²Rn + daughter nuclei and, the distribution of single and multiple decays from single points over the storage period of the autoradiograph. The information enables the frequency of single and multiple hits to sensitive cells in the lung to be calculated. This is an important step in estimating the frequency of radiation induced mutations. ii) The absolute abundance of alpha-active nuclides present at each site. This quantity is determined at particular locations in lung such as bifurcations in the major airways, in corresponding positions on the posterior aspect of the trachea and bronchus and parenchymal lung for each of the five lobes and in the lymph nodes. The information is obtained in normal lung over a wide span of age. This overall information may be used to study the deposition, retention and clearance patterns of different alpha-emitting elements with associated differences in size and physical and chemical nature. (orig./HSI)

[en] The description of the set of semiconductor detectors with a large area and complicated shapes used in the Radium Institute for the calibration of alpha activities of targets from fissile radionuclides including low radioactive targets and targets with complex configurations will be presented. (author). Abstract only

[en] Full text of publication follows. This introduction to the interactive session will simply be based on statements related to the future of therapy in nuclear medicine with some emphasis on the use of alpha-emitters. Some hypotheses will be developed on topics such as 'How will look nuclear medicine in 2025?', 'Do we have enough information to support the use of alpha in therapy?' 'Does it make sense to develop alpha-labelled molecules without long term financial commitment?', 'Will sufficient amounts of radionuclides available when the drugs will be ready for marketing?', 'Do we know enough about alpha emitters toxicity?', 'Is personalized medicine really the solution of the future of health care?', 'How can we convince authorities about the advantages of alpha labelled molecules?', 'Is the development of alpha RIT more expensive or more difficult than beta RIT?', 'Where are all the beta-emitter under development gone?', 'With alpha-emitters, are we speaking about 2025 or 2050?', 'Will Xofigo be a success?', 'What will be the real role of pharmaceutical companies in radiotherapy?', 'Who are the most afraid about radioactivity, the patients or the authorities?'. The speaker will provide his own opinion about each topic. Will you agree or not with him? What is your opinion? (author)

[en] A scintillation method for determining the activity of α-emitting nuclides in aerosol filters is proposed. The method involves dissolving the filter in an organic solvent, adding a phosphor to the resulting solution, drying the sample, and measuring the activity of the radionuclides. The dependences of the α-emission detection efficiency on the phosphor content, the filter material, and colorless and colored substances in the analyzed samples are studied. Thus, up to 12.5 mg/cm² of dispersed white solid on the filter does not interfere with the activity measurement. The method enables the activity of α-emitting nuclides in aerosol filters to be reliably measured without using approximate correction coefficients that take into account absorption of α-particles by the filter material and dispersed solid. 10 refs., 3 figs., 1 tab

[en] A prototype posting-in hatch, mounted vertically in the top panel of a highly active glovebox has been radiologically evaluated in the Fuels Laboratory, AEEW. This simple, air-lock type system of 100 mm diameter has pneumatically operated and interlocked lids and a low velocity, inward purge, supplied by the glovebox depression. The hatch proved extremely reliable and very easy to operate. More than 1200 simulated posting movements were carried out and a > 8 order of magnitude reduction in aerosol concentration was recorded from the active glovebox to the monitoring environment. (author)

No abstract available