A Case of an Average CT in Thoracic Cavity PET/CT for Respiration-induced Artifacts

Positron emission tomography/computed tomography (PET/CT) provides fusion of both anatomical and functional information. But, due to the temporal difference of positron emission tomography (PET) and helical computed tomography (HCT), the respiratory motion during PET acquisition leads to artifacts in PET/CT. Average computed tomography (ACT) and PET have a similar temporal resolution and it has been shown to improve registration of the computed tomography (CT) and PET data for PET/CT imaging of the thorax. In this article, we presented a patient of right parotid gland adenoid carcinoma had right parotid gland dissection and radiotherapy. The patient underwent a PET/CT scan for evaluation and following treatment planning. Then, the ACT data was obtained by cine CT scan for attenuation correction (AC) of the PET data. Both the ACT and the HCT data were used for AC of the same PET data. Differences between the two PET sets, the PET data corrected by HCT (PET_(HCT)) and the PET data corrected by ACT (PET_(ACT)), was quantified by analyzing image alignment and maximum of standard uptake value (SUV_(max)). The increase 21% in SUV_(max) and improved registration with PET_(ACT) compared to the results from PET_(HCT) was observed in this patient.