| CPC A61K 51/088 (2013.01) [A61K 51/0497 (2013.01)] | 5 Claims |
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1. A method for producing an 225Ac solution, the method comprising:
a step (I) of irradiating a 226Ra target with at least one type of particles selected from protons, deuterons, and photons to generate two or more actinium radioisotopes (Ac) including at least 225Ac;
a step (II) of dissolving the 226Ra target after the step (I) to obtain a Ra—Ac solution (1) that contains 226Ra and Ac;
a step (III) of separating 226Ra and Ac originating from the 226Ra target and contained in the Ra—Ac solution (1) to obtain an Ac solution (2) that has a higher Ac concentration than the Ra—Ac solution (1);
a step (IV) of allowing 224Ac and 226Ac in the Ac solution (2) to decay to obtain a Ra—Ac solution (3) containing radium isotopes (Ra) resulting from decay; and
a step (V) of separating Ra and Ac contained in the Ra—Ac solution (3) to obtain an Ac solution (4) that has a higher 225Ac concentration than the Ra—Ac solution (3),
when a time from completion of the step (I) to start of the step (III) is represented by T1, and
a time from completion of the step (III) to start of the step (V) is represented by T2,
T1 and T2 satisfy a relationship of T2>T1,
wherein a ratio 140La content/225Ac content of a 140La content to an 225Ac content in the Ac solution (4) is 1×10−5 or less at seven days after completion of the step (V).
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