Establishing inherent uncertainty in the shifts determined by volumetric imaging

For the successful radiotherapy treatment delivery, accurate positioning of patient on a day to-day basis on the treatment couch at the predetermined treatment position is of utmost importance. Volumetric imaging is perhaps the best tool among the several imaging modalities that are available to the radiation oncology team members to achieve this goal. It can determine both the translational shifts and as well as the rotational shifts (six dimensions). This study was performed to establish the inherent uncertainty associated with such a volumetric imaging system in determining the positional shifts