Comparison between parallel hole and rotating slat collimation

In this study, we compared the performance of parallel hole (PH) and rotating slat (RS) collimations at equal spatial resolution. Based on mathematical calculations, we derived the linear relationship between the optimal collimator aperture and the target spatial resolution for each collimator, and calculated the gain in signal-to-noise ratio (RS over PH) for the central point of a homogeneous symmetrical phantom using these optimized collimator parameters. These results were supported by an efficient analytical Fisher information-based method. The collimations were compared for both planar imaging and volume imaging. The main results are: 1) For the same target resolution, the optimal system resolution depends on the collimator and the imaging mode (planar or volume). 2) RS has lower variance than PH when the object is smaller than the detector.