Strategies of improving lesion detection in wide-angle digital breast tomosynthesis (dbt) with angular dose distribution and detector design

Cancerous masses are more conspicuous in wide-angle digital breast tomosynthesis (DBT) due to better depth resolution and tissue separation, while the detection of subtle microcalcifications (MC) is challenging. This study aims at providing guidance for a new DBT system design to enhance lesion detection through variable angular dose image acquisition and improved detector performance. Digital breast phantoms were generated, and projection images were simulated using the FDA VICTRE tool 1. Simulated masses and clusters of MC were inserted at different locations of the digital breast phantom. Projection images were simulated with 28 kVp W/Rh energy spectrum, 200 μm thick amorphous selenium (a- Se) direct active matrix flat panel imager (AMFPI), and 50° angular range with 25 views. The impact of a-Se detector performance, i.e., complementary metal-oxide-semiconductor (CMOS) active pixel sensor (APS) versus AMFPI, with different electronic noise and pixel pitches, was investigated. Even and uneven angular dose distribution schemes (ADS) were designed to test the combined effect of image acquisition setting and detector performance on lesion detection. 2D Filtered Channel observer (FCO) and 3D Channelized Hotelling observer (CHO) were employed to evaluate lesion detectability under different scenarios. The results demonstrated the improvement of direct conversion CMOS APS on the detectability of small MC clusters by reducing FSM, improving DQE at a lower dose, and improve the sharpness of reconstructed MC. The uneven dose distribution benefits the detection of MC without compromising mass detection in FBP reconstructed volumes with slice thickness filter for wide angle DBT.