ORNL production of the experimental alpha emitters bismuth-213 and actinium-225 for medical applications
- Oak Ridge National Lab., TN (United States)
- Advanced Integrated Management Services, Inc., Knoxville, TN (United States)
Due to their short range in tissue (50 to 80 {micro}m), alpha emitters are of considerable interest for certain radioimmunotherapy applications. These applications require the destruction of single cells or small clusters of cells. The radioisotope {sup 213}Bi, which is milked from {sup 225}Ac, is an alpha emitter that is currently being used in phase-1 human leukemia trials at the Memorial Sloan-Kettering Cancer Center. The most readily achievable route for producing {sup 225}Ac generators involves separating ingrown {sup 229}Th daughters from the {sup 233}U parent. Thorium-229 is then used as a parent generator for {sup 225}Ac. Thorium-229 is easier to handle than {sup 233}U, which is fissile and typically contains trace concentrations of {sup 232}U. Uranium-232 has a radioactive daughter, {sup 208}Tl, which emits a high-energy (2.6-MeV) photon when it decays. An alternative method for producing {sup 229}Th is through neutron irradiation of {sup 227}Ra. However, this method is less desirable due to the production of very high levels of {sup 228}Th. Thorium-229 accumulates in stored {sup 233}U oxides by natural decay. The current ORNL process for extracting {sup 229}Th from stored {sup 233}U oxides includes dissolution, strong-acid anion exchange, and calcination of the uranium. This ORNL process has provided high-purity {sup 225}Ac generators to medical researchers. Bismuth-213 has been extracted and used in initial human trials and already has demonstrated a potency and specificity for attacking cancerous cells.
- OSTI ID:
- 644233
- Report Number(s):
- CONF-980606--
- Journal Information:
- Transactions of the American Nuclear Society, Journal Name: Transactions of the American Nuclear Society Vol. 78; ISSN TANSAO; ISSN 0003-018X
- Country of Publication:
- United States
- Language:
- English
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