Early Evaluation of the Response of Large B Cell Non Hodgkin's Lymphoma to Chemotherapy by PET/CT

Patients affected with non-Hodgkin's large B-cell lymphoma are treated by chemotherapy. The evaluation of the response to this treatment is made by Positron Emission Tomography (PET/CT) in many centres where this technology is available. Presently PET scans and CT scans are being performed before treatment, after 4 cycles of chemotherapy and a few months after the end of treatment. The goal of this study is to determine if it is possible to evaluate the efficiency of chemotherapy treatments after one cycle of treatment instead of waiting after 4 cycles, using a new scanner that combines PET and CT modalities. Data available from studies on these combined exams suggest that PET/CT helps to rapidly evaluate the response of the chemotherapy treatment. We also want to verify if some pathological characteristics measured from tumor cells will enable doctors to predict in advance the response to treatment.