What techniques do you use to minimize gas artifacts on cone beam CT when treating upper abdominal lesions?

Gas and motion artifacts are significant causes of poor image quality for imaging studies that have a long acquisition time such as cone beam CT. The problem areas are in the upper abdomen where the impact of respiratory motion is greatest. Organ motion can be controlled in most patients, but the presence of gas cannot. This is a great question with no good solutions that I am aware of. In the supine position, stomach and duodenal gas are the most common culprits. This often creates artifact in and around the target and OARs. Although the gas cannot be controlled, the impact of the gas can be managed. When imaging is critical, using a shorter acquisition time (spotlight technique, 40 secs), controlling organ motion, and treating patients wi...