# Alpha-emitter nanogenerators and daughter trapping

Source: https://onco.cc/technologies/alpha-nanogenerators/  
OnCo record `alpha-nanogenerators` (Technology). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Actinium-225 releases four alpha particles as it decays, but the daughters escape and irradiate the kidneys and salivary glands. Nanocarriers try to hold them in place.

## Summary

The therapeutic power of actinium-225 comes from its decay chain, but recoil energy ejects daughter nuclides from any chelator, causing off-target dose. Nanoparticle carriers (lanthanum phosphate, titanium dioxide, liposomes) and polymer cages are designed to retain daughters long enough for them to decay inside the tumour. Retention above 90% has been reported in animals; no such construct had reached human trials by 2026.

## Fields

- Kind: Technology
- Status: preclinical
- Last checked: 2026-09-08
- Tags: frontier; radical
- Principle: Encapsulating the parent nuclide in a solid-state or multi-shell carrier physically retains recoiling daughters, converting a leaky decay chain into a contained one.
- Strengths: Could remove the main toxicity limit on actinium therapy; Multiplies alpha dose per targeting event; Compatible with existing targeting ligands
- Limitations: No human data; Nanoparticle biodistribution favours liver and spleen; No trodden regulatory path for a radioactive nanomaterial

## Sources

- ClinicalTrials.gov: actinium-225: https://clinicaltrials.gov/search?term=actinium-225

## Connected records

- fronts: [Radiopharmaceuticals & Theranostics](https://onco.cc/fronts/radiopharma/)
- technologies: [Actinium-225 supply: thorium stocks, accelerators and radium targets](https://onco.cc/technologies/actinium-225-supply/), [Radioligand therapy (beta emitters)](https://onco.cc/technologies/radioligand-therapy/), [Targeted alpha therapy](https://onco.cc/technologies/targeted-alpha-therapy/)
- companies: [Aktis Oncology](https://onco.cc/companies/aktis-oncology/), [Perspective Therapeutics](https://onco.cc/companies/perspective-therapeutics/), [TerraPower Isotopes](https://onco.cc/companies/terrapower-isotopes/)
- terms: [Alpha vs beta emitters](https://onco.cc/terms/alpha-vs-beta/), [Dosimetry](https://onco.cc/terms/dosimetry/)
- roadmaps: [Radical oncology: what could change the war by 2035](https://onco.cc/roadmaps/frontier-2035/)

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