Optimizing a multiple-pinhole SPECT system using the ideal observer

Abstract

In a pinhole imaging system, multiple pinholes are potentially beneficial since more radiation will arrive in the detector plane. However, the various images produced by each pinhole may multiplex (overlap), possibly decreasing image quality. In this work we develop the framework for comparing various pinhole configurations using ideal-observer performance as a figure of merit. We compute the ideal-observer test statistic, the likelihood ratio, using a statistical method known as Markov-Chain Monte Carlo. For different imaging systems, we estimate the likelihood ratio for many realizations of noisy image data both with and without a signal present. For each imaging system, the area under the ROC curve provides a meaningful figure of merit for hardware comparison. In this work we compare different pinhole configurations using a three-dimensional lumpy object model, a known signal (SKE), and simulated pinhole imaging systems. The results of our work will eventually serve as a basis for a design of high-resolution pinhole SPECT systems.