Visit 3: Day of 18F-FLT-PET/CT: The patient will have an intravenous line placed in the hand or arm, 18F-FLT-PET/CT will be given by 1-2 minute IV push, and the dose administered will be approximately 5 mCi (+/- 20% dose). After approximately 60 +/- 10 minutes of uptake time, the patient will be positioned supine in the PET/CT scanner for standard whole body PET/CT scan from the skull base to mid-thigh. This scan will take approximately 20-30 min. The window from FLT PET/CT baseline study to initiation of chemotherapy should be no more than 30 days.