The image reconstruction influence in relative measurement in SPECT / PET / CT animal

The objective of this study was to evaluate spatial resolution and the influence of different reconstruction methods in a FLEX Triumph ™ Pre-Clinical Imaging System images applied to mice C57BL6 dosimetry in a new radiopharmaceuticals development for humans use. CT and SPECT images were obtained from a homemade phantom containing four spheres with diameters (d) simulating iodine-accumulating injuries at University Hospital (HU / UFRJ). The SPECT images were reconstructed with filtered back projection method (FBP) and the influence in resolution and partial volume effect was evaluated for different filters: Hamming, Hann and Ramp. The resolution found was 9.3 to 9.4 mm, significantly lower than the value provided by the manufacturer, 1.6 mm. Thus, the protocol for mice can be optimized by FBP reconstruction method and Hamming filter, 0.5 cut-off , yielding a resolution from 9.3 to 9.4 mm. This value indicates that iodine-accumulating regions diameter below 9.3 mm is not quantifiable.