4D-CBCT image reconstruction

4D-CBCT image reconstruction

Four-dimensional CT (4DCT) captures respiratory motion as a series of CT images along the time axis. The basic concept is to reconstruct each image using only the projection data belonging to the same respiratory phase. However, CBCT acquired on a rotating-gantry treatment machine rotates slowly, making it difficult to capture sufficient respiratory information, and the number of projections is limited. Selecting only the projections of the same respiratory phase reduces the usable data even further, leading to degraded image quality. In other words, patients receive the radiation dose of the CBCT scan, yet not all of it contributes to image quality.

We reconstruct 4D-CBCT images for each respiratory phase using all of the acquired projection data, and combine this with our proprietary image processing to achieve excellent image quality.