Quantitative Evaluation of Four-Dimensional versus Three-Dimensional Reconstruction on XCAT Phantom Under Different Sampling Rates

Precise targeting of tumors is essential in radiotherapy. Imaging the lungs, however, is correlated with motion artifacts due to respiration. Motion artifacts influence achieving the required image quality and can cause uncertainty in target precision and dose calculations. Respiratory-correlated four-dimensional cone beam computed tomography (4D-CBCT) is an imaging technique proposed to resolve motion artifacts. However, the scans generated from this method are associated with streaking artifacts due to the limited number of projections binned within different respiratory phases. The main objective of this study is to provide a systematic comparison and evaluation of the quality of 4D images produced at several sampling rates. The evaluation is done in terms of the streaking artifacts, signal-to-noise ratio, and sharpness of edges in structures affected by respiratory motion. Experimental results showed that increasing the number of projections used in reconstructing 4D images improve image quality.