PT - JOURNAL ARTICLE AU - Marlies C. Goorden AU - Frans van der Have AU - Rob Kreuger AU - Ruud M. Ramakers AU - Brendan Vastenhouw AU - J. Peter H. Burbach AU - Jan Booij AU - Carla F.M. Molthoff AU - Freek J. Beekman TI - VECTor: A Preclinical Imaging System for Simultaneous Submillimeter SPECT and PET AID - 10.2967/jnumed.112.109538 DP - 2013 Feb 01 TA - Journal of Nuclear Medicine PG - 306--312 VI - 54 IP - 2 4099 - http://jnm.snmjournals.org/content/54/2/306.short 4100 - http://jnm.snmjournals.org/content/54/2/306.full SO - J Nucl Med2013 Feb 01; 54 AB - Today, PET and SPECT tracers cannot be imaged simultaneously at high resolutions but require 2 separate imaging systems. This paper introduces a Versatile Emission Computed Tomography system (VECTor) for radionuclides that enables simultaneous submillimeter imaging of single-photon and positron-emitting radiolabeled molecules. Methods: γ-photons produced both by electron–positron annihilation and by single-photon emitters are projected onto the same detectors by means of a novel cylindric high-energy collimator containing 162 narrow pinholes that are grouped in clusters. This collimator is placed in an existing SPECT system (U-SPECT-II) with 3 large-field-of-view γ-detectors. From the acquired projections, PET and SPECT images are obtained using statistical image reconstruction that corrects for energy-dependent system blurring. Results: For PET tracers, the tomographic resolution obtained with a Jaszczak hot rod phantom was less than 0.8 mm, and 0.5-mm resolution images of SPECT tracers were acquired simultaneously. SPECT images were barely degraded by the simultaneous presence of a PET tracer, even when the activity concentration of the PET tracer exceeded that of the SPECT tracer by up to a factor of 2.5. Furthermore, we simultaneously acquired fully registered 3- and 4-dimensional multiple functional images from living mice that, in the past, could be obtained only sequentially. Conclusion: High-resolution complementary information about tissue function contained in SPECT and PET tracer distributions can now be obtained simultaneously using a fully integrated imaging device. These combined unique capabilities pave the way for new perspectives in imaging the biologic systems of rodents.