Application of TlBr to nuclear medicine imaging

Abstract

Thallium bromide (TlBr) has been under development for room temperature gamma ray spectroscopy due to high density, high Z and wide bandgap of the material. Furthermore, its low melting point (460 °C), cubic crystal structure and congruent melting with no solid-solid phase transitions between the melting point and room temperature, TlBr can be grown by relatively simple melt based methods. As a result of improvements in material processing and detector fabrication over the last several years, TlBr with electron mobility-lifetime products (μ_eτ_e) in the mid 10^-3 cm²/V range has been obtained. In this paper we are going to report on our unipolar charging TlBr results for the application as a small animal imaging. For SPECT application, about 5 mm thick pixellated detectors were fabricated and tested. About 1 % FWHM at 662 keV energy resolution was estimated at room temperature. By applying the depth correction technique, less than 1 % energy resolution was estimated. We are going to report the results from orthogonal strip TlBr detector for PET application. In this paper we also present our latest detector highlights and recent progress made in long term stability of TlBr detectors at or near room temperature. This work is being supported by the Domestic Nuclear Detection Office (DNDO) and the Department of Energy (DOE).