TABLE 3.

Overview of current and potential production methods for four key alpha-emitting isotopes.

Isotope	Half-life	Isotope availability	Main production approach	Current and potential production methods
				Method	Status
211At	7.21 h	Very low	Cyclotron	209Bi(α,2n)211At	Production
				232Th(p,x)211Rn	Research
				238U(p,x)211Rn	Research
				209Bi(7Li,5n)211Rn	Research
				209Bi(6Li,4n)211Rn	Research
212Pb/212Bi	10.64/1 h	Scaling	Generator decay	224Ra/212Pb generator	Production
225Ac	9.92 days	Low–growing	Generator decay	229Th/225Ac generator	Production
				226Ra(p,2n)225Ac	Research
				226Ra(γ,n)225Ra	Potential
				226Ra(n,2n)225Ra	Potential
				226Ra(d,3n)225Ac	Potential
				232Th(p,x)225Ac	Research
227Th	18.7 days	High	Generator decay	227Ac decay	Production
				235U decay	Production

Potential routes to increase production for each isotope include: ²¹¹At: explore production at existing and upcoming facilities and ²²¹Rn generator routes; ²¹²Pb/²¹²Bi: increase production of ²²⁸Th; ²²⁵Ac: provide additional stock of ²²⁹Th, scale up spallation on ²³²Th production and new cyclotron methods; ²²⁷Th: produce ²²⁷Ac via neutron irradiation of ²²⁶Ra. Source: (74, 94, 95).