Abstract
1070
Objectives: 123I-Metaiodobenzylguanidine (MIBG), a norepinephrine analog, has been applied to imaging cardiac sympathetic nerve distribution and function. Pre-clinical observations widen our clinical applications. The study was undertaken to observe the usefulness of a clinical camera equipped with a modified pin-hole collimator in 123I-MIBG imaging of rodent hearts. Methods: We tested the detection ability of the modified 2-mm aperture with 1mm keel-edge (Tungsten/Carbon, 95/5%) by the phantom and compared to the commercialized 3-mm aperture. Ten rats weighted around 300 g each were imaged under anesthesia at 15 min (early) and 4 h (delay) after 150 MBq of 123I-MIBG intravenous injection. Planar anterior views with a preset time (10 min) mode were performed for early and delayed pin-hole images using either 2- or 3-mm aperture at a distance of less than 0.5 cm and a 256 × 256 matrix gamma camera (Picker Prism 1000 XP). Measurements of the cardiac 123I-MIBG uptake and washout rates were as described (J Nucl Med 2005; 46:1090). Results: In phantom studies, we found that the 2-mm aperture created much higher resolution than that of the 3-mm aperture (FWHM, 2.1 vs. 5.0 mm) (figure). In rat studies, a promising cardiac imaging was achievable in 10 min by the 2-mm aperture system in both visual (figure) and semi-quantitative analyses. The averaged cardiac uptake was 1.99± 0.12 and the averaged washout rate was 64.2± 5.1 (mean± SD). Conclusions: Our data suggested that a pin-hole collimator equipped with a modified 2-mm aperture may provide a convenient means for imaging rodent cardiac sympathetic function.
- Society of Nuclear Medicine, Inc.