Hybrid Spectral CT: Combining rapid kVp-switching and dual-layer detectors for high sensitivity iodine imaging

Over the past two decades, spectral computed tomography (CT) has undergone significant advancements, particularly in the realm of diagnostic accuracy, prompting a surge in clinical studies. This research examines the development of a new hybrid spectral CT system that combines a clinical-grade rapid kVp-switching X-ray tube with a dual-layer detector, aiming to boost quantitative spectral imaging performance in different clinical applications. The performance of the system was evaluated using varying tube voltages, duty cycles, and rotation times to enhance spectral outcomes. This experimental setup allowed for adjustments in parameters such as tube voltage pairs (140/80 and 120/70 kVp), duty cycles (ranging from 15/85 to 75/25), and tube currents (300 and 570 mA), which were tested on both large and small phantoms. The quantitative analysis was conducted using a two-input projection-based material decomposition approach. The study highlighted the impact of spectral weighting schemes on noise reduction and quantification bias in iodine density images. Results indicated that the maximum spectral separation scheme presented the least bias, suggesting its potential for improved clinical applications and outcomes. In conclusion, the research underscores the potential of integrating dual-energy technologies in hybrid spectral CT systems.