Positron Emission Tomography Molecular Imaging for Phenotyping and Management of Lymphoma.

Positron emission tomography (PET) represents molecular imaging for non-invasive phenotyping of physiological and biochemical processes in various oncological diseases. PET imaging with 18 F-fluorodeoxyglucose ( 18 F-FDG) for glucose metabolism evaluation is the standard imaging modality for the clinical management of lymphoma. One of the 18 F-FDG PET applications is the detection and pre-treatment staging of lymphoma, which is highly sensitive. 18 F-FDG PET is also applied during treatment to evaluate the individual chemo-sensitivity and accordingly guide the response-adapted therapy. At the end of the therapy regiment, a negative PET scan is indicative of a good prognosis in patients with advanced Hodgkin's lymphoma and diffuse large B-cell lymphoma. Thus, adjuvant radiotherapy may be alleviated. Future PET studies using non- 18 F-FDG radiotracers, such as 68 Ga-labeled pentixafor (a cyclic pentapeptide that enables sensitive and high-contrast imaging of C-X-C motif chemokine receptor 4), 68 Ga-labeled fibroblast activation protein inhibitor (FAPI) that reflects the tumor microenvironment, and 89 Zr-labeled atezolizumab that targets the programmed cell death-ligand 1 (PD-L1), may complement 18 F-FDG and offer essential tools to decode lymphoma phenotypes further and identify the mechanisms of lymphoma therapy.