RT Journal Article SR Electronic T1 VECTor: A Preclinical Imaging System for Simultaneous Submillimeter SPECT and PET JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 306 OP 312 DO 10.2967/jnumed.112.109538 VO 54 IS 2 A1 Marlies C. Goorden A1 Frans van der Have A1 Rob Kreuger A1 Ruud M. Ramakers A1 Brendan Vastenhouw A1 J. Peter H. Burbach A1 Jan Booij A1 Carla F.M. Molthoff A1 Freek J. Beekman YR 2013 UL http://jnm.snmjournals.org/content/54/2/306.abstract 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.