Canadian Nuclear Facility Plans to Increase Production of Radioactive Ac-225 by 30 Times.

[NNadir]

Last edited Sat Jul 29, 2023, 01:50 AM - Edit history (1)

CNL eyes dramatic increase in Ac-225 production

Canadian Nuclear Laboratories (CNL) has announced an agreement with the Sylvia Fedoruk Centre for Nuclear Innovation - part of the University of Saskatchewan - that will enable it to increase by more than 30 times its current production of the rare actinium-225 (Ac-225) radioisotope.

Ac-225 has shown great promise for therapeutic use in targeted alpha therapy (TAT), where an alpha-emitter is combined with a protein or antibody that specifically targets and kills cancer cells while leaving the surrounding healthy tissue unharmed. However, research and clinical trials have been hampered by very limited supplies of the isotope.

The new agreement will see the Fedoruk Centre irradiate targets of radium-226 - extracted from legacy medical waste by CNL - at the Saskatchewan Cyclotron Facility. The irradiated targets will be returned to CNL's Chalk River campus in Ontario for separation and processing. CNL will then ship the materials to German radiopharmaceutical biotech company ITM, with which it signed a Memorandum of Understanding in 2021, for refinement and distribution.

Announcing the new agreement at the 11th International Conference on Isotopes in Saskatoon, Saskatchewan, CNL President and CEO Joe McBrearty said it has taken "many years" of work in radiochemistry, physics, engineering, waste management, remote tooling and instrumentation to reach this point, but the initiative will "dramatically" increase availability of the radioisotope to the radiopharmaceutical community. "Following a short ramp-up phase, CNL expects to produce more than 30 times the actinium-225 that it does today, enabling the necessary clinical research and testing to bring many promising new cancer treatments to life," he said...

This looks like spallation technology based on an accelerator. It works, surely, but perhaps there is a better approach.

I don't wish to second guess, but I will. Thorium-229, the parent of Ac-225 is itself the decay product of U-233, produced in the thorium cycle. At this time, the US has the world's largest inventory of U-233 (although regrettably there are plans to dispose of it) which can be milked for Th-229, which in turn can be milked for Ac-225.

The decay of U-232, always formed in thorium nuclear fuels, either by serial neutron reactions of Th-230 to Pa-231 to U-232 or by U-233(n, 2n) reactions decays with a 69 year half-life to Th-228, which can be isolated in relatively pure form from isolated uranium obtained from thorium fuels. Th-228 can undergo readily 228Th( n,? )Th229 reactions, providing a relatively pure source of Th-229 from which Ac-225 can be milked. I believe this approach has been explored and possibly practiced at Oak Ridge National Laboratory. Ac-225 is a very powerful alpha particle emitter (as is its decay daughters with extremely short half-lives.

The approach to targeting cancer cells is to design an antibody to display proteins on cancer cells, attach a linker to the antibody which is in turn attached to a complexation agent, generally a DOTA type complex that carries the radionuclide directly to cancer cells with high specificity. This allows for the highly selective destruction of cancer cells to the exclusion of normal cells.

It's an elegant way to attack tumor tissues.

[EarnestPutz]

1. Always enjoy your well informed take on this stuff. "Second guessing" is perfectly....

....acceptable when you know the subject. I shouldn’t be surprised to find out that even medical uses for radioactive isotopes require long, onerous approval procedures, though certainly less than building a reactor. Just curious though, what does thirty times the amount of Ac-225 amount to? I have no idea if it’s 100 grams or kilograms.

[littlemissmartypants]

2. Combine those clinical outcomes with some predictive AI and they may really

Accelerate their progress. Pun intended.

[TexasTowelie]

3. There is a typo in the third paragraph from the end.

The last sentence should read "which can be milked for Th-229" rather than Th-239.

Interesting article about the pharmaceutical properties of the isotope.

[NNadir]

4. Thank you. You're right. I'll correct it.