title: Performance evaluation of a newly developed high-resolution, dual-head animal SPECT system based on the NEMA NU1-2007 standard.
abstract: Small-animal single-photon emission computed tomography (SPECT) system plays an important role in the field of drug development and investigation of potential drugs in the preclinical phase. The small-animal High-Resolution SPECT (HiReSPECT) scanner has been recently designed and developed based on compact and high-resolution detectors. The detectors are based on a high-resolution parallel hole collimator, a cesium iodide (sodium-activated) pixelated crystal array and two H8500 position-sensitive photomultiplier tubes. In this system, a full set of data cor- rections such as energy, linearity, and uniformity, together with resolution recovery option in reconstruction algorithms, are available. In this study, we assessed the performance of the system based on NEMA-NU1-2007 standards for pixelated detector cameras. Characterization of the HiReSPECT was performed by measure- ment of the physical parameters including planar and tomographic performance. The planar performance of the system was characterized with flood-field phantom for energy resolution and uniformity. Spatial resolution and sensitivity were evaluated as functions of distance with capillary tube and cylindrical source, respectively. Tomographic spatial resolution was characterized as a function of radius of rotation (ROR). A dedicated hot rod phantom and image quality phantom was used for the evaluation of overall tomographic quality of the HiReSPECT. The results showed that the planar spatial resolution was ~ 1.6 mm and ~ 2.3 mm in terms of full-width at half-maximum (FWHM) along short- and long-axis dimensions, respectively, when the source was placed on the detector surface. The integral uniformity of the system after uniformity correction was 1.7% and 1.2% in useful field of view (UFOV) and central field of view (CFOV), respectively. System sensitivity on the collimator surface was 1.31 cps/μCi and didn't vary significantly with distance. Mean tomographic spatial resolution was measured ~ 1.7 mm FWHM at the radius of rotation of 25 mm with dual-head configuration.The measured performance demonstrated that the HiReSPECT scanner has acceptable image quality and, hence, is well suited for preclinical molecular imaging research.
authors.affiliation: Research Center for Molecular and Cellular Imaging, Tehran University of Medical Sciences, Department of Radiation Medicine Engineering. vahide.moji@gmail.com.
authors.forename: Vahideh
authors.initials: V
authors.lastname: Moji
authors.forename: Navid
authors.initials: N
authors.lastname: Zeratkar
authors.forename: Mohammad Hossein
authors.initials: MH
authors.lastname: Farahani
authors.forename: Mahmoud Reza
authors.initials: MR
authors.lastname: Aghamiri
authors.forename: Salar
authors.initials: S
authors.lastname: Sajedi
authors.forename: Behnoosh
authors.initials: B
authors.lastname: Teimourian
authors.forename: Pardis
authors.initials: P
authors.lastname: Ghafarian
authors.forename: Saeed
authors.initials: S
authors.lastname: Sarkar
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Ay
mesh_terms: D000465:Algorithms; D000818:Animals; D015902:Gamma Cameras / Q000592:standards; D006801:Humans; D015899:Tomography, Emission-Computed, Single-Photon / Q000592:standards*