Cyclotron production of Ac-225 for targeted alpha therapy

Appl Radiat Isot. 2005 Mar;62(3):383-7. doi: 10.1016/j.apradiso.2004.06.013.


The feasibility of producing Ac-225 by proton irradiation of Ra-226 in a cyclotron through the reaction Ra-226(p,2n)Ac-225 has been experimentally demonstrated for the first time. Proton energies were varied from 8.8 to 24.8 MeV and cross-sections were determined by radiochemical analysis of reaction yields. Maximum yields were reached at incident proton energies of 16.8 MeV. Radiochemical separation of Ac-225 from the irradiated target yielded a product suitable for targeted alpha therapy of cancer.

MeSH terms

  • Actinium / chemistry*
  • Actinium / therapeutic use
  • Alpha Particles / therapeutic use*
  • Cyclotrons
  • Nuclear Medicine / methods*
  • Protons
  • Radiotherapy / methods
  • Radium / chemistry*


  • Protons
  • Actinium
  • Radium