Abstract: A method for producing Pb-212 isotope comprises introducing Th-228 into an emanation box. The emanation box comprises an emanation source comprising a high-surface area material. The method also includes introducing a carrier gas into the emanation box through a carrier gas feed. The method also includes separating the Rn-220 from the carrier gas in the one or more Rn-220 targets, directing the carrier gas out of the one or more Rn-220 targets through a carrier gas exhaust port, directing a liquid through a liquid feed into the one or more Rn-220 targets, and allowing the Rn-220 to undergo radioactive decay into Pb-212 isotope within the one or more Rn-220 targets. The liquid dissolves the Pb-212 isotope produced by radioactive decay of Rn-220 within the one or more Rn-220 targets. The method further includes directing the liquid containing the Pb-212 isotope from the one or more Rn-220 targets to a Pb-212 collection container, and separating the Pb-212 isotope from the liquid.