 - Determine the positive and negative predictive values of early positron emission tomography PET scanning using fludeoxyglucose F 18 in terms of the probability of patients with newly diagnosed intermediate- or high-grade non-Hodgkins lymphoma who achieve or do not achieve complete remission, after treatment with 1 course of rituximab and combination chemotherapy comprising cyclophosphamide, doxorubicin, vincristine, and prednisone. 