Production of High Specific Activity Radioisotopes via the Szilard-Chalmers Method, Using the UC-Irvine TRIGA® Reactor
Abstract
ABSTRACT OF THE DISSERTATION
Production of High Specific Activity Radioisotopes via the Szilard-Chalmers Method, Using the UC-Irvine TRIGA® Reactor
By
Leila Safavi-Tehrani
Doctor of Philosophy in Chemical and Biochemical Engineering
University of California, Irvine, 2016
Professor Mikael Nilsson, Chair
Radioactive isotopes have become an important imaging, diagnostic and therapeutic tool in the medical field. For example, the neutron rich samarium isotope of 153Sm has been proven to have desirable characteristics for treatment of bone cancer. However, for medical purposes, the radioisotope must be produced with high specific activity, i.e. low concentration of inactive carrier, so they are beneficial for therapy and the concentration of the metal ions does not exceed the maximum sustainable by the human body. The objective of the research study was to produce radioisotopes, specifically the lanthanides, with increased specific activity in a small-scale research reactor using the Szilard-Chalmers method. The preliminary experimental results showed a decrease of 34% in the amount of Lanthanide needed for a typical medical procedure1. An innovative experimental setup was also developed that instantaneously separated the radioactive recoil product formed during irradiation from the bulk of non-radioactive ions. The instant separation prevented the recoiled radioactive nucleus from reforming its original bonds within the target matrix and chemically separated it from the non-radioactive target matrix, resulting in a radioisotope product with increased specific activity. The novel experimental setup resulted in further improvement of the radiolanthanide enrichment factors, and ultimately resulted in a decrease of 96% in the amount of lanthanide needed for typical medical applications. The methods for preparation and synthesis of the material used for irradiations, the results of enrichment factors and extraction yields in radioactive lanthanide solutions are discussed. The obtained results will be compared to previously published methods and their corresponding results.