| dc.description.abstract | The use of the alpha particle emitting radionuclide ²¹¹At for clinical therapy of primary and metastatic tumors via targeted methods is an attractive modality for increasing cancer management and survivability. While the potential for therapeutic use is great, widespread commercial production capability of ²¹¹At is currently very limited. Development of targetry and distillation apparatus utilizing commercially available and/or easily adaptable technology is of paramount importance in developing and maintaining the preclinical and clinical availability of ²¹¹At. Previous preliminary studies have proven the feasibility of ²¹¹At production at the Texas A&M Cyclotron Institute utilizing the ²⁰⁹Bi (α, 2n) ²¹¹At reaction. The goal of this research is to further develop routine ²¹¹At production equipment and methods to facilitate ongoing in vitro, in vivo, and preclinical research.
Drawing from previous research, an inclined external solid target was developed capable of undergoing extended (8+ h) irradiations of 29-MeV (7.25 MeV u¯¹) alpha particles at currents up to 7 μAₑ. A dry distillation apparatus and process were developed to recover the astatine while negating radiochemical contamination from target byproduct materials. Several production irradiations were performed with favorable results. Production yields ranged between 10.73 – 39.17 MBq µAp¯¹ h¯¹ (0.290 – 1.058 mCi µAp¯¹ h¯¹ ), consistent with published yields, at average beam intensities on the order of 5-10 times that used in previous experiments (2-3 µAp). Recovered yields were on the order of 740 MBq (20 mCi) per production run after initial development (median 22.09 mCi ± 0.77). No contamination by ²¹⁰At or ²¹⁰Po was detected in any of the experiments performed.
Overall, production utilizing these methods has proven feasible for small-scale studies utilizing 1-20 mCi per experiment. Development of further process automation and miniaturization, as well as quality assurance and current good manufacturing process (cGMP) protocols, will be required for forthcoming standardized production. Proposed improvements and protocols are provided for future work. | en |
