Non-Hodgkin lymphoma (NHL) is one of the more frequent cancers in the western world with approx. 800 new cases annually in Denmark. Diffuse large B-cell lymphoma (DLBCL) in Denmark accounts for almost 40% of newly diagnosed NHL cases. Treatment with the combination of chemotherapy and monoclonal antibodies has significantly improved prognosis over the past decade, but a large proportion of patients with DLBCL will continue to relapse with our current treatment options. Therefore, there is a need for reliable methods for detection of treatment response as early as possible in the treatment course in order to identify patients who respond poorly to standard treatment and potentially would benefit from a change in treatment strategy. This has still not been established, but a valid early marker is required in order to allow randomized trials of treatment stratified by early response. One of the most promising applications of PET is the metabolic assessment of the early response of cancer treatment.

This study is a national prospective multicenter study emanating from the Danish Lymphoma Group (DLG). Patients are scanned after each of the early 4 cycles of chemo therapy. The aim is to establish the correct timing of response evaluation. Additionally, the investigators wish to investigate the optimal qualitative and quantitative method of response assessment in order to predict post-therapeutic remission and long-term prognosis.This study will contribute to interim-PET being implemented in the most optimal way in daily clinical practice.

Inclusion Criteria:

-Age>18 years

Exclusion Criteria:

• Previously treatment with chemotherapy or irradiation
• Primary CNS lymphoma
• Recurrent lymphoma
• Transformation from indolent lymphoma
• Presence of diabetes mellitus, HIV, chronic inflammatory disease or infections
• Planned for curative treatment

Patients with newly diagnosis of Diffuse Large B-cell lymphoma