18F FLT Imaging Studies of Treatment Response for Lung Cancer and Thymoma

Background: * (18)F FLT, a thymidine analog, has uptake in tumors that correlates with proliferative rates and may be an early predictor of tumor response. * Due to uptake in inflammatory tissues, routinely used (18)F FDG PET/CT is often unable to distinguish therapeutic response from reactive change early in therapy. * Molecularly targeted therapies relating to the MEK kinase pathway in non small cell lung cancer (NSCLC) and the IGF pathway (anti-IGF-1R monoclonal antibodies) in thymoma, affect tumor proliferation. * We intend to explore the potential utility of (18)F FLT PET/CT imaging as an early marker of therapeutic response in molecularly targeted therapies relating to the MEK kinase pathway in NSCLC and the IGF pathway in thymic tumors. Objectives: -To explore the relationship between change in (18)F FLT tumor uptake (pre-treatment and soon after initiation of treatment (2 weeks)) and progression free survival in NSCLC patients treated with AZD6244 and in thymoma patients with IMC-A12, Cixutumumab Eligibility: * Subjects with pathology proven lung cancer or thymoma enrolled in an NCI therapy protocol. * Participant must be 18 years or older and have ECOG Performance of less than or equal to 2. * Patients must have measurable disease by RECIST criteria. * Patients must have the ability to provide informed consent. All subjects must sign a document of informed consent indicating their understanding of the investigational nature and risks of the study before any protocol related studies are performed. Design: -This is a pilot study which will incorporate (18)F FLT and (18)F FDG PET/CT imaging sessions prior to therapy with AZD6244, Selumetinib, in NSCLC and IMC-A12, Cixutumumab, in thymoma, and 2 weeks (+/- 4 days) following therapy initiation. The imaging parameters will be evaluated with respect to clinical response (as determined under the referring protocol). We expect to enroll 24 evaluable patients in this single center study.