Image Quality Performance of a Dedicated Cardiac Discovery NM 530c SPECT: Impact of Time Acquisition and Reconstruction Parameters

The aim of this study is to evaluate the impact of acquisition time and reconstruction parameters in image quality in a dedicated cardiac Discovery NM 530c CZT SPECT scanner. Anthropomorphic torso phantom with a cardiac insert and a cold lesion starting with 84 kBq/ml, 62 kBq/ml and 3 kBq/ml in myocardium, liver and background, respectively, simulated high-dose stress ^99mTc acquisition. During two half-lives, images were acquired hourly to simulate lower doses, using both 3 and 5 min time acquisition. Reconstruction parameters were used separately per type of acquisition (low-dose and high-dose), according to manufacturer recommendation. Image quality and cold lesion visibility were evaluated using normalized standard deviation (NSD), ventricle-wall cavity contrast (VCC), contrast-to-noise ratio (CNR), and lesion effective contrast (EC). Variations in acquisition time did not affect quality parameters and lesion visibility for the appropriate reconstruction parameters, mainly in higher activities. However, image quality indicators are highly sensitive to the reconstruction parameters, producing significant differences (p < 0.05) in NSD, VCC, CNR and EC. Concluding, the reconstruction parameters need to be chosen carefully, considering patient´s characteristics and administered activity, in order to produce the best relation image quality/lesion visibility and dose.