Microcolumnar CsI(Tl) films for small animal SPECT

Microcolumnar CsI(Tl) films in the range of 50 to 500 μm thickness are routinely used in digital X-ray imaging as they simultaneously provide a high spatial resolution and excellent X-ray absorption. The use of such films for radionuclide imaging has not yet been possible due to the unavailability of thick films required to provide adequate stopping power for gamma ray energies typically used in such applications. We report here the development of up to 2.6 mm thick microcolumnar CsI(Tl) films well suited for small animal SPECT imaging using such radioisotopes as ¹²⁵I (∼30 keV) and ^99mTc (140 keV). This paper discusses scintillator fabrication, characterization, and demonstrates its use for high resolution SPECT imaging. The data show that a resolution of 400 μm in reconstructed images can be achieved using this approach.