Fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography as a diagnostic tool in therapeutic evaluation of lymphoma after completion of therapy

This study aimed at assessment of the role of (PET/CT) in lymphoma after completion of therapy to differentiate post-treatment fibrosis from residual viable tumor and being familiar with the limitations and interpretative pitfalls of PET/CT. Method and materials: The present study was performed on 50 patients (27 males and 23 females). 18F-FDG was injected IV one hour before performing the study. Contrast enhanced CT was performed followed by PET. Results: After the end of therapy; PET/CT revealed (38%) of cases showed a partial regression, (28%) of cases showed a progressive disease, (22%) of cases with complete metabolic disease remission, (8%) of cases showed a stationary disease and the remaining (4%) of cases showed mixed response to therapy. CT only agreed with PET/CT in 76% of the cases. Some physiologic uptake often occurs after treatment in (4%) of patients. PET/CT has 100% sensitivity,68.75 % specificity, 87.17% PPV, 100% NPV and 90% accuracy in treatment response of lymphoma; compared to 94.1% sensitivity and 50% specificity, 80% PPV, 80% NPV and 80% accuracy for CECT. Conclusion: PET/CT is a multimodality technique that can accurately monitor the treatment response of lymphoma. It can differentiate residual mass containing viable tumor from post treatment fibrosis