# Regional cyclotron hubs for actinium-225 with an agreed actinium-227 impurity limit

Source: https://onco.cc/ideas/idea-reg-ac225-accelerator-pharmacopoeia/  
OnCo record `idea-reg-ac225-accelerator-pharmacopoeia` (Idea). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Actinium-225 can be made in particle accelerators, but the product contains a trace of a long-lived impurity that regulators have not agreed how to handle. Settle the limit and build the hubs.

## Summary

Proton irradiation of radium-226 yields actinium-225 with a small admixture of actinium-227 (half-life 21.8 years), while electron linac photonuclear and high-energy spallation routes differ in impurity profile. Without a harmonised monograph, each producer negotiates specifications with each regulator, slowing investment. The proposal is a joint European, US and Japanese pharmacopoeia monograph setting actinium-227 and other radionuclidic impurity limits based on dosimetry and waste handling, paired with public co-investment in three to five regional cyclotron or linac hubs sized for clinical supply.

## Fields

- Kind: Idea
- Last checked: 2026-09-08
- Hypothesis: A harmonised monograph published within two years is followed by at least three accelerator producers reaching GMP supply, and clinical trial sponsors report isotope supply as the limiting factor in fewer than 10% of alpha therapy trials, down from the majority today.
- Rationale: Molybdenum-99 supply diversified only when regulators agreed specifications for non-HEU and accelerator-produced material. Investment follows regulatory certainty.
- Proposed test: Commission the dosimetric analysis of actinium-227 contamination at candidate limits, convene the pharmacopoeial groups, and track producer investment decisions and trial supply reports before and after publication.
- Maturity: early-clinical
- Actor: regulator

## Sources

- Bottleneck evidence (Manufacturing cost and time for living and radioactive medicines): Hernandez, Prasad & Gellad, Total costs of chimeric antigen receptor T-cell immunotherapy (JAMA Oncology 2018): https://doi.org/10.1001/jamaoncol.2018.0977

## Connected records

- technologies: [Targeted alpha therapy](https://onco.cc/technologies/targeted-alpha-therapy/)
- terms: [Alpha vs beta emitters](https://onco.cc/terms/alpha-vs-beta/), [Dosimetry](https://onco.cc/terms/dosimetry/)
- bottlenecks: [Manufacturing cost and time for living and radioactive medicines](https://onco.cc/bottlenecks/b-manufacturing-cell-therapy/), [Regulatory divergence between regions](https://onco.cc/bottlenecks/b-regulatory-fragmentation/)
- key papers: [Total Costs of Chimeric Antigen Receptor T-Cell Immunotherapy](https://onco.cc/key-papers/paper-hernandez-jama-oncol/)

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