TY - JOUR T1 - Optimizing PET scan protocol for small animal study: Correlation between scan duration, injected activity, target dimension, target-to-background ratio and imaging performance JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 2087 LP - 2087 VL - 52 IS - supplement 1 AU - Ching-Ching Yang Y1 - 2011/05/01 UR - http://jnm.snmjournals.org/content/52/supplement_1/2087.abstract N2 - 2087 Objectives Increasing the injected activity or the scanning duration is usually considered to achieve target imaging performance in an animal PET study, but may thus affect the processes under study due to the increased radiation and anesthetic dose. The aim of this study was to investigate how PET image quality behave when varying scan duration and injected activity. Methods PET data sets of a cylindric water phantom (4 cm in diameter and 8.2 cm in height) including spheres with different object properties were simulated using the GATE Monte Carlo simulation software. A multivariate approach was used to investigate the simultaneous effects of target dimension (Dtarg = 4, 5, 6, 8, 12 mm in diameter), target-to-background ratio (T/B ratio = 2, 4, 8, 12, 20), scan duration (Tacq = 30, 60, 90 min) and injected activity (Aacq = 4.7×104, 9.3×104, 1.4×105 Bq/ml) on contrast-to-noise ratio (CNR) and background variability (BV). Results The T/B ratio resulted as the most significant predictor of CNR, followed by Dtarg, Tacq and Aacq of the given sphere. Dtarg, Tacq and Aacq were the most important, the second most important and the least important predictor of BV, respectively. The fittings of both models were good with R2 larger than 0.80 in both cases. Conclusions Our preliminary results should provide practical guidance on how to define appropriate scan duration and radioactivity to achieve the target imaging performance when imaging object with different intrinsic characteristics ER -