Speaker
Description
Developing effective cancer treatment strategies remains a global challenge. Targeted alpha therapy (TAT) with Bi-213 as alpha emitter has emerged as a promising approach, offering cytotoxic effects on cancer cells while minimizing damage to healthy tissue. However, Bi-213 production is limited due to the lack of sorbent materials that are both selective and resistant to acidic environments and radiation, hindering efficient separation of Bi-213 from its parent Ac-225. Given the urgent need for novel Ac-225/Bi-213 separation systems, known as Bi-213 generators, the potential of phosphate-modified titania as a sorbent material for their development is investigated. The synthesized materials were characterized by various techniques, such as zeta potential analysis, DRIFT spectroscopy, argon sorption and P NMR, while batch sorption tests were conducted with lanthanum (non-radioactive surrogate for Ac-225) and bismuth to evaluate the sorption behaviour. Furthermore, the acidic and radiolytic stability of the phosphate-modified titania was evaluated by exposure to nitric acid and by irradiation with a Co-60 gamma source, respectively. The results showed that titania exhibited a high and selective bismuth uptake at low pH, regardless of the modification degree. Lanthanum removal, on the other hand, only reached similar levels to bismuth at pH ≥ 3 and with a sufficient degree of surface phosphate groups. Desorption experiments demonstrated efficient bismuth elution from the sorbent, although selectivity was limited due to substantial co-elution of lanthanum. With respect to stability, titania showed high resistance to acidic degradation, but the leaching of phosphate surface groups did diminish sorption efficiency. Finally, exposure to gamma irradiation up to 5 MGy doses revealed an excellent radiolytic stability. In conclusion, this study demonstrates that, although modified titania needs further optimization before it could be applied in direct Bi-213 generators, unmodified titania could be envisaged as a highly promising sorbent for inverse Bi-213 generators.