Multi-Source Cone Beam CT for Image-Guided Radiation Therapy*

Image-guided radiation therapy (IGRT) uses real-time medical imaging to enhance treatment site visualization and ensure precise radiation delivery. Cone-beam computed tomography (CBCT) is the current gold standard imaging modality for IGRT, but it suffers from limitations such as poor soft tissue contrast, inaccurate Hounsfield Unit (HU) measurements, and image artifacts. A multiple-source CBCT (ms-CBCT) system offers a promising alternative by reducing scatter and improving both contrast and HU accuracy. In this study, a benchtop imaging system capable of acquiring both standard CBCT and ms-CBCT scans was used to evaluate performance differences. A chest phantom containing three HU-specific nodules was imaged and reconstructed with both modalities. Analysis of the reconstructions revealed that ms-CBCT improved HU measurement accuracy by 9% and a reduction in cupping artifacts relative to standard CBCT, highlighting its potential for enhanced IGRT imaging.