Single-Exposure Material Decomposition in Chest Tomosynthesis with a CdTe Photon-Counting Detector

Abstract

Dual-energy material decomposition enables differentiation of soft tissue and bone in X-ray imaging; however, conventional methods require two sequential exposures, increasing radiation dose, acquisition time, and the risk of misregistration. This study presents a single-exposure material decomposition method using a cadmium telluride (CdTe)-based photon-counting detector (PCD) integrated with digital tomosynthesis (DTS). The proposed framework consists of three key steps: 1) simultaneous acquisition of low- and high-energy projections with dual thresholds (25 and 65 keV), 2) calibration-based decomposition using a PMMA–Al wedge phantom, and 3) projection-domain material separation followed by DTS reconstruction. Validation through both simulation and experimental studies demonstrated accurate separation of soft-tissue and bone components, high projection-level decomposition precision (RMSE: 0.052 for PMMA; 0.012 for Al), and improved perceptual image quality (SSIM: 0.979 and 0.974; PSNR: 37.6 and 38.6 dB). Compared with conventional energy-integrating detector (EID)-based dual-energy methods, the proposed PCD-based approach achieved superior structural preservation, contrast uniformity, and image interpretability. Beyond chest imaging, this single-exposure PCD framework is also applicable to non-medical X-ray applications, such as industrial nondestructive testing, security screening, and material characterization.