Microdosimetry of $\alpha$ emitters with mobile daughters
In plain words
Alpha-emitting drugs release a chain of short-lived radioactive descendants, which can break free of the carrier molecule and travel elsewhere in the body before decaying. Where that dose ends up is not known.
Precise statement
Determine the absorbed dose at cellular scale from Ac-225 and Ra-223 chains, including recoil-induced release of daughters (Fr-221, Bi-213, Pb-209 for Ac-225) and their redistribution, given alpha ranges of 40 to 100 micron and hit numbers of order a few per cell nucleus. An answer is a microdosimetric specific-energy distribution per organ and tumour, with measured daughter redistribution fractions.
What would settle it
Direct measurement of daughter biodistribution combined with stochastic microdosimetric calculation validated by cellular damage endpoints.
Status in the literature
Unverified note
Daughter redistribution, particularly to kidney and bone marrow, was recognized but not quantified in patients as of 2025.