Abstract: ¹⁸F-FDG PET is an important imaging technique in the stage of patients with lymphoma and more sensitive and accurate than gallium scintigraphy. Persistently positive PET imaging during and after chemotherapy have a high sensitivity for predicting subsequent relapse. A negative PET imaging at the end of therapy provides favorable prognostic information. Compared to other conventional imaging modalities, ¹⁸F-FDG PET significantlyimproves the accuracy of imaging tumors in initial staging, and monitoring of therapy response of lymphoma.