Patent Number: 048760730
Section: summary

FIELD OF THE INVENTION There are provided generators for short-lived radionuclides for use in medicine, and especially in diagnostic methods such as angiocardiography. There is also provided a novel process for the production of an osmium complex which is used in one type of such generators. Other objects of the invention and features thereof will become apparent hereinafter. BACKGROUND OF THE INVENTION First pass radionuclide angiography following bolus administration has been used principally for the detection and quantitation of intracardiac shunts, evaluation of right and left ventricular ejection fraction, measurement of cardiac output and various other cardiac parameters. This technique has proved its potential for non-invasive evaluation of a variety of congenital and acquired cardiovascular disorders, especially in children. A radionuclide of short half-life must be used, and the one in use to the largest extent at present is technetium-99m, which is used mainly as sodium pertechnetate with a .gamma. of 140 keV, with a physical half-life of 6 hours. There have also been proposed generator systems of Cd-109.fwdarw.Ag-109m and Os-191.fwdarw.Ir-191m. In the case of the Cd/Ag generator the half life of 1.26 years of Cd poses a problem should breakthrough occur. There has been developed a rubidium-81 krypton-81m generator with Rb half-life of 4.7 hours and Krypton half-life of 13.1 seconds. Krypton-81m is well suited for long studies but is not suitable for angiocardiography as it is readily eliminated by the lungs. Another ultra-short lived generator is Ba-137m with a half-life of 2.55 minutes. However, its photon energy of 662 keV is too high for use with gamm cameras of the Anger type. Yet another generator is the Hg-195.fwdarw.A-195m generator, the daughter having a 30.5 seconds half-life, with the parent having a 40 hour half-life. SUMMARY OF THE INVENTION There is provided a generator for the production of ultra-short lived radionuclides for use in medical diagnostics, and especially for use in angiocardiography in adults and in children. (1) The novel type of radionuclide generator is based on the concept of providing an inorganic support column to which there is applied a suitable ion exchange agent adapted to firmly bind a suitable compound or complex of the parent radioactive element, there being established a steady state between said parent compound and the daughter nuclide of short life time which results from said parent nuclide. The invention is mainly illustrated with reference to a preferred embodiment which is based on .sup.191 Os giving .sup.191m Ir. As pointed out in the following, other generators can be provided based on systems like .sup.178 W .sup.178 Ta, or .sup.195m Hg .sup.195m Au, and the like. The following description describes in detail the embodiment of the generator based on Os/Ir. Thus, the preferred embodiment of a generator for short-lived radionuclides according to the present invention, is based on the use of a column charged with .sup.191 Os which has a half-life of 15.5 days, giving .sup.191m Ir which has a half-life of 4.9 seconds, giving a gamma of 129 keV and X-rays of 65 keV, used advantageously in conjunction with a scavenger minimizing the breakthrough of Os to very low values. There is also provided a novel process for the production of an osmium complex which is used for charging the column, which process is comparatively simple, gives a pure product in a high yield, and which complex has advantageous properties for the intended purposes.