The development of alpha-emitting radiopharmaceuticals using <sup>211</sup>At requires quantitative determination of the time-dependent nature of the <sup>211</sup>At biodistribution. However, imaging-based methods for acquiring this information with <sup>211</sup>At have not found wide-spread use because of its low abundance of decay emissions suitable for external detection. In this publication we demonstrate the theranostic abilities of the <sup>211</sup>At/<sup>209</sup>At isotope pair and present the first-ever <sup>209</sup>At SPECT Images. <b>Methods:</b> The VECTor microSPECT/PET/CT scanner was used to image <sup>209</sup>At with a collimator suitable for the 511 keV annihilation photons of PET isotopes. Data from distinct photopeaks of the <sup>209</sup>At energy spectrum (195 keV (22.6%), 239 keV (12.4%), 545 keV (91.0%), a combined 782/790 keV peak (147%), and <sup>209</sup>Po x-rays (139.0%)) were independently evaluated for use in image reconstructions using Monte Carlo (GATE) simulations and phantom studies. <sup>209</sup>At-imaging <i>in vivo</i> was demonstrated in a healthy mouse injected with 10 MBq of free [<sup>209</sup>At]astatide. Image-based measurements of <sup>209</sup>At uptake in organs of interest - acquired in 5-minute intervals - were compared to <i>ex vivo</i> gamma counter measurements of the same organs. <b>Results:</b> Simulated and measured data indicated that - due to the large amount of scatter from high energy (>750 keV) gammas - reconstructed images using the x-ray peak outperformed those obtained from other peaks in terms of uniformity and spatial resolution, determined to be <0.85 mm. <sup>209</sup>At imaging using the x-ray peak revealed a biodistribution that matched the known distribution of free astatide, and <i>in vivo</i> image-based measurements of <sup>209</sup>At uptake in organs of interest matched <i>ex vivo</i> measurements within 10%. <b>Conclusion:</b> We have acquired the first <sup> 209</sup>At SPECT images and demonstrated the ability of quantitative SPECT imaging with <sup>209</sup>At to accurately determine astatine biodistributions with high spatial and temporal resolution.