title: Evaluation of a matched filter resolution recovery reconstruction algorithm for SPECT-CT imaging.
abstract: OBJECTIVE
  The aim of our study was to assess improvements in spatial resolution and noise control from the application of the Astonish resolution recovery algorithm for single photon emission computed tomography imaging. Secondary aims were to compare acquisitions made with low-energy general purpose collimators with those obtained using low-energy high-resolution collimators in this context and evaluate the potential of a finer matrix to improve image quality further.
  
  
  METHODS
  A Tc-filled Jaszczak phantom with hot spheres was used to assess contrast and noise. A National Electrical Manufacturers Association triple line source single photon emission computed tomography resolution phantom was used to measure spatial resolution. Acquisitions were made using both low-energy high-resolution and low-energy general purpose collimators.
  
  
  RESULTS
  Compared with standard ordered subsets expectation maximization reconstructions, the resolution recovery algorithm resulted in a higher spatial resolution (8 vs. 14 mm full-width at half-maximum) leading to reduced partial volume effects in the smaller Jaszczak spheres. Higher image contrast was achieved alongside lower levels of noise. An edge enhancement artefact was observed in the resolution recovery corrected images. An overestimate of the target-to-background activity was also observed for the larger spheres.
  
  
  CONCLUSIONS
  The use of such an algorithm results in images characterized by increased spatial resolution and reduced noise. However, small sources of the order of 2-3 cm can be significantly overenhanced.
authors.affiliation: Nuclear Medicine, Barts Health NHS Trust, West Smithfield, London, UK.
authors.forename: Eoin
authors.initials: E
authors.lastname: O'Mahoney
authors.forename: Iain
authors.initials: I
authors.lastname: Murray
mesh_terms: D000465:Algorithms; D016477:Artifacts; D003287:Contrast Media / Q000494:pharmacology; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods; D064847:Multimodal Imaging / Q000379:methods*; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography; D015203:Reproducibility of Results; D012984:Software; D013667:Technetium / Q000494:pharmacology*; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D013667:Technetium