A technique to reduce lung and liver misregistration in PET/CT.

Background: A common problem when interpreting PET/CT results is the misregistration that occurs from breathing artefact. Artefact occurs as a result of the tidal breathing patterns throughout the PET acquisition. New technology and techniques are constantly evolving to improve breathing artefact in order to allow better interpretation of scans. Aim(s): The respiratory gating system employed in our PET/CT is very time consuming and result in long scan times. In a busy department additional acquisitions create time management problems due to high patient throughput. Our aim was to find an alternative simple protocol to reduce breathing artefact. Method(s): A one bed static acquisition was acquired following a whole body PET/CT scan with significant misregistration in either a lung or liver lesion. The patient is placed on the bed supine, with a firm strap around their lower chest. Instructions are given to breathe using their upper chest wall in isolation, limiting diaphragmatic motion. The patient is put on 2 litre of oxygen to allow for better oxygenation, and to reduce any distress to the patient. A1 bed PET/CT is acquired over the region of interest at 2/mins per bed to allow for enough counts but reduced time for patient. Result(s): Our new breathing acquisition has vastly improved PET to CT data registration and in a majority of patients providing a more accurate localisation and SUVs of lung and liver lesions. Conclusion(s): Dedicated acquisitions to reduce breathing artefact can be an effective way of reducing misregistration in departments that are time poor or respiratory gating is unavailable.