Fast Microcolumnar Scintillator for Radionuclide Imaging

75096-Despite excellent scintillator properties and its use in a wide variety of applications, CsI(Tl) has not been used for radionuclide imaging in medical applications. The primary reason is the presence of a strong afterglow component in its scintillation decay, which reduces the energy resolution. Another reason is the absence of thick, pixelated scintillator structures, which are needed to overcome the traditional tradeoff between detection efficiency and spatial resolution, thereby allowing the full potential of current imaging modalities (e.g., Scanning Photon Emission Tomography) to be realized. This project addresses these issues by using co-dopants capable of suppressing the afterglow of CsI(Tl) and by developing thick microcolumnar scintillator structures. As added benefits: (1) the co-dopants are expected to enhance the prompt emission of CsI(Tl) without sacrificing any of its excellent scintillation properties, and (2) the microcolumnar structure will allow thick, high efficiency films to be fabricated while maintaining very high spatial resolution. Phase I will develop co-doped CsI(Tl) films of required geometry for radionuclide imaging. Also, vapor deposition protocols will be established for producing stoichiometrically balanced, thick, microcolumnar films of the co-doped CsI(Tl). The resulting scintillator structures will be characterized, and the superiority of the approach will be demonstrated by comparing the data to that obtained using other scintillators that are currently employed in radionuclide imaging. Commercial Applications and Other Benefits as described by the awardee: The modified scintillator should have widespread use in small animal/human SPECT/CT imaging systems in particular, and nuclear medicine systems in general. Additionally, the readout sensor should have applications in high-speed and ultra-high-speed x-ray imaging, nondestructive testing, and homeland security.