Can Positron Emission Tomography (PET) or PET/Computed Tomography (CT) Acquired in a Nontreatment Position Be Accurately Registered to a Head-and-Neck Radiotherapy Planning CT?

It is possible to incorporate PET and/or PET/CT acquired in diagnostic positions into the treatment-planning process through the use of advanced image registration algorithms, but precautions must be taken, particularly when delineating tumor volumes in the neck. Acquisition of PET/CT in the treatment-planning position would be the ideal method to minimize registration errors.