Assessing the performance of C-SPECT cardiac tomographer using GATE-based Monte Carlo simulations

We construct three-dimensional GATE-based models of the C-SPECT proposed cardiac tomographer and of a typical dual-head gamma camera. The models are used to compare the two systems performance in geometric efficiency and image reconstruction. A digital phantom that includes a cylindrical annulus that emulates the myocardium is used for imaging. The working example of C-SPECT is not representing the final optimized design. Maximizing the number of nonoverlapping projections coming from the C-SPECT slits, we confirm that C-SPECT demonstrates an improvement by a factor of 2.5 in system geometric efficiency compared to the dual-head camera. For statistics close to a clinical acquisition, and for a resolution in the center of the FOV close to 9.5 mm, C-SPECT´s higher sensitivity results in better contrast in the center of FOV, but decreased uniformity (due to angular undersampling) in the cylindrical annulus for the given high spatial resolution. The artifacts are removed when we double the angular sampling by acquiring half the data after a 7-degree rotation of the phantom. The improvement in system geometric efficiency can eventually lead to faster imaging, lower patient dose, or improved quality of myocardium images. Our modeling and simulations infrastructure will be used for the final optimization of C-SPECT.