title: Gaussian prefiltering of 123I DAT SPECT images when using depth-independent resolution recovery.
abstract: Previously we have investigated a depth-independent compensation for collimator detector response (CDR) included in the OSEM reconstruction, intended for SPECT images that have been corrected for scatter and septal penetration using convolution-based methods. In this work, the aim was to study how different filtering strategies affect contrast as a function of noise when using Gaussian smoothing filters in combination with the above-described CDR compensation. The evaluation was performed for (123)I dopamine transporter (DAT) SPECT images. Prefiltering with 2D Gaussian filter kernels, where the deterioration in resolution is included in the depth-independent CDR compensation, was compared to conventional postfiltering with 3D Gaussian filter kernels. Images reconstructed without filtering are also included in the comparison. It was found that there is little benefit in noise reduction when using CDR compensation. However, this variant of prefiltering gives consistently higher contrasts as a function of noise compared with the postfiltering alternative, and that could be of interest when using other types of filters with contrast improving properties.
authors.affiliation: Department of Radiation Sciences, Radiation Physics, Umeå University, SE-901 87 Umeå, Sweden. anne.larsson@vll.se
authors.forename: Anne
authors.initials: A
authors.lastname: Larsson
authors.forename: Susanna Jakobson
authors.initials: SJ
authors.lastname: Mo
authors.forename: Torbjörn
authors.initials: T
authors.lastname: Sundström
authors.forename: Katrine
authors.initials: K
authors.lastname: Riklund
mesh_terms: D000465:Algorithms; D001921:Brain / Q000000981:diagnostic imaging*; D050483:Dopamine Plasma Membrane Transport Proteins / Q000627:therapeutic use*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007457:Iodine Radioisotopes; D019047:Phantoms, Imaging; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*