There is a present and future need for the medical isotope Actinium-225, currently in short supply worldwide. Only a couple manufacturers produce it in very low quantities. In roughly the past 10 years the medical community has explored the use of Ac-225 and its daughter Bismuth-213 for targeting a number of differing cancers by way of Targeted Alpha Therapy (TAT). This method utilizes the alpha-decay of both Ac-225 (half-life 10 days) and Bi-213 (half-life 46 min) to kill cancerous cells on a localized basis. Maximum energy is delivered to the cancer cells thereby greatly minimizing healthy tissue damage.
This research proposes a production method using a high-energy photon spectrum (generated by a linear accelerator or LINAC) to irradiate a sample of Radium-226 (half-life 1600yrs). The photo-neutron reaction liberates neutrons from Ra-226 atoms leaving behind Radium-225 (half-life 14.7 days). Ra-225 decays naturally through beta emission to Ac-225. Previous research demonstrated it is possible to produce Ac-225 using a LINAC; however, very low yields resulted which questioned the feasibility of this production method. This research proposes a number of LINAC and radium sample modifications that could be greatly increase yield amounts for practical use.
Additionally, photo-neutron cross-section data for Ra-226 was used, which led to improved yield calculations for Ra-225. A MATLAB® model was also created, which enables users to perform quick yield estimates given several key model parameter inputs. Obtaining a sufficient supply of radium material is also of critical importance to this research. Therefore information was gathered regarding availability and inventory of Radium-226. This production method would serve as a way to not only eliminate many hazardous radium sources destined for interim storage, but provide a substantial supply of Ac-225 for future cancer treatment. / Master of Science
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/50984 |
| Date | 12 June 2013 |
| Creators | VanSant, Paul Daniel |
| Contributors | Mechanical Engineering, Pierson, Mark Alan, Haghighat, Alireza, Policke, Timothy A. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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