J Nucl Med. 2008; 49 (Supplement 1):404P
Instrumentation & Data Analysis: InstrumentationInstrumentation Posters |
Effect of the positron range on the spatial resolution of a new generation pre-clinical PET-scanner using F-18, Ga-68, Zr-89 and I-124
Jorn van Dalen1,
Eric Visser1,
Peter Laverman1,
Wouter Vogel1,
Wim Oyen1,
Frans Corstens1 and
Otto Boerman1
1 Nuclear Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands
1700
Objectives: The intrinsic resolution of small-animal PET scanners has improved to a level where the positron range of the radionuclide has an influence on the effective spatial resolution. The aim of this study was to quantify the impact of the positron range on the image resolution of a high-resolution small-animal PET scanner.
Methods: Phantom studies were performed using a Siemens Inveon pre-clinical PET-scanner, with an intrinsic resolution of 1.5 mm (FWHM). Images were acquired using F-18 (maximum positron range in water: 2.3 mm), Ga-68 (8.9 mm), Zr-89 (3.6 mm), and I-124 (6.9 and 10.2 mm). First, the FWHM image resolution was determined using hot capillaries with an inner diameter of 0.3 mm, filled with 30 MBq/mL, placed in a water environment to simulate in-vivo imaging. Second, the resolution limit for both hot and cold spots was determined with visual analysis of a mini phantom with hot and cold rod inserts (diameters: 1.2–4.8 mm).
Results: The FWHM of the profiles of the hot capillaries was 1.4, 1.7, 3.0 and 3.0 mm, for F-18, Zr-89, Ga-68 and I-124, respectively. The resolution limits of hot and cold rods are shown in the table.
Conclusions: The image resolution of a PET scanner with a 1.5 mm intrinsic system resolution is decreased significantly by the large positron ranges of Ga-68 and I-124. This has major impact on the detection of small lesions and the ability to distinguish lesions that are close together and should be considered when planning small-animal imaging.
