Simulation-based optimization of a parallel collimator for scintimammography using a new CdZnTe gamma-camera architecture (HiSens)

Because of the trade-off between spatial resolution and sensitivity resulting from the collimation, conventional Anger NaI-based gamma-cameras have reached their limits. To overcome these limitations, the HiSens architecture was proposed. Based on the use of a pixelated CdZnTe (CZT) detector, this architecture is characterized by an accurate 3D localization of the interactions inside the detector using a fine sampling of the CZT detector and the Depth Of Interaction (DOI) information. To reduce acquisition time or to improve image quality for a given acquisition time, a high aperture collimator is associated with the HiSens architecture. The aim of the present work is to determine the characteristics of a parallel hole collimator dedicated to scintimammography applications when using the HiSens architecture. To reach this goal, a Detective Quantum Efficiency (DQE) study was first used and the results were then validated using numerical simulations. They show that in geometric conditions corresponding to scintimammography, a 3.6 increase in sensitivity can be achieved while preserving the LEHR image quality, suggesting that the acquisition duration or the injected activity could be reduced by a factor 3.6.