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DOE OSTI2023

Opportunities for Bright Beam Generation at the Argonne Wakefield Accelerator (AWA)

Bright electron beams have played a critical role in many recent advances in accelerator technology. Producing bright beams via photo-emission is ultimately limited by the mean transverse energy (MTE), which is determined by the photocathode. This paper discusses the opportunity to generate bright electron beams using an upgraded version of the Argonne Wakefield Accelerator (AWA) photo-injector. The focus of this study is to examine the optimal configurations of the AWA photo-injector to produce 100 pC with a ∼100 nm transverse emittance (corresponding to a 5D brightness B5≥1015 A·m−2). The numerical optimization of the AWA photo-injector operating point, including realistic electromagnetic field maps, is presented for the different types of photocathodes under consideration.

Frame, Emily↗

DOE OSTI2023

Coded aperture and Compton imaging for the development of 225 Ac‐based radiopharmaceuticals

Abstract Background Targeted alpha‐particle therapy (TAT) has great promise as a cancer treatment. Arguably the most promising TAT radionuclide that has been proposed is 225 Ac. The development of 225 Ac‐based radiopharmaceuticals has been hampered due to the lack of effective means to study the daughter redistribution of these agents in small animals at the preclinical stage. Purpose The ability to directly image the daughters, namely 221 Fr and 213 Bi, via their gamma‐ray emissions would be a boon for preclinical studies. That said, conventional medical imaging modalities, including single photon emission computed tomography (SPECT) based on nonmultiplexed collimation, cannot be employed due to sensitivity limitations. Methods As an alternative, we propose the use of both coded aperture and Compton imaging with the former modality suited to the 218‐keV gamma‐ray emission of 221 Fr and the latter suited to the 440‐keV gamma‐ray emission of 213 Bi. Results This work includes coded aperture images of 221 Fr and Compton images of 213 Bi in tumor‐bearing mice injected with 225 Ac‐based radiopharmaceuticals. Conclusions These results are the first demonstration of visualizing and quantifying the 225 Ac daughters in small animals through the application of coded aperture and Compton imaging.

62 RADIOLOGY AND NUCLEAR MEDICINE↗