Comparison of Small Field of View Gamma Camera Systems for Scintimammography

Objective: To compare the performance characteristics of three compact gamma camera systems for scintimammography.

Methods: A multi-crystal NaI system (Dilon 6800), a multicrystal CsI system (Digirad 2020tc Imager) and a prototype cadmium zinc telluride (CZT) detector were evaluated using a breast phantom with simulated tumours of 1.8-9.8 mm in diameter and a tumour to background ratio of 5.6 : 1. A conventional Anger-based gamma camera was also evaluated for comparative purposes.

Results: The conventional gamma camera had the highest intrinsic sensitivity of the four systems and utilized the highest resolution collimator. However, the prototype CZT and the CsI systems yielded the best spatial resolution over the range 0-5 cm from the collimator face and better visualized small (5-7 mm) tumours.

Conclusion: In addition to the advantage of close proximity to the breast, two of the three compact detectors offered superior performance to a conventional gamma camera for scintimammography.