[Application of 18F-FDG PET/CT scan in following-up of nasopharyngeal carcinoma after radiotherapy].

Background & Objective: Local relapse,tumor residue, and whole body metastases of nasopharyngeal carcinoma (NPC) after radiotherapy were mainly confirmed by CT, MRI, SPE/CT, and PET examinations. This study was to discuss the value of F-18-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (PET/CT) in detecting suspected recurrence or tumor residue, and whole body metastases of NPC after radiotherapy.

Methods: PET/CT were performed on 38 NPC patients 3-36 months after radiotherapy. The images of PET/CT, CT, and PET were observed. PET standardized uptake value (SUV) was calculated, and SUV of > 2.5 was considered as positive. The Patients were divided into 4 groups by diagnosis: (1) no recurrence/residue, and no whole body metastases; (2) with recurrence/residue, but no whole body metastases; (3) no recurrence/residue, but with whole body metastases; (4) with both recurrence/residue and whole body metastases. Diagnoses of all patients were referred to the proved follow-up clinical information. The following-up time was 6-10 months.

Results: The sensitivity, and specificity of PET/CT (100%,and 89.5%) were better than that of CT alone (77.8%, and 84.2%), a litter better than that of PET alone (100%, and 80.0%).

Conclusions: FDG-PET scan is a better tool than CT alone for the detection of recurrene or residue, and whole body metastases of NPC, a litter better than PET alone. PET/CT may provide valuable information for judging whether the focus is metastasis.