Abstract: Non-invasively predicting and monitoring the effects of cancer therapy in responding patient populations, and thus personalizing cancer therapy, is a significant challenge. This dissertation reports the use of Positron Emission Tomography (PET) for developing radiolabeled tyrosine kinase inhibitors (TKIs) and glycolytic inhibitors as PET biomarkers that might be used to select subset patient populations benefiting from targeted cancer treatments. Identification of 4-[3-(2-[18F]Fluoroethyl)anilino] quinazoline-6-acrylamide ([18F]FEQA), 4-(3'-chloro-4'-[18F] fluoroanilino)-7-methoxy-6-(3-morpho-linopropoxy)quinazoline ([18F]Gefitinib), and [18F]fluoro-2-deoxy-D-glucose (FDG) allowed for cell culture studies, in vivo biodistribution experiments, toxicity tests, and dosimetry calculations that resulted in tracer delivery to patients. This work highlights the tremendous potential for using PET to measure the biodistribution, pharmacokinetics, and pharmacodynamics of radiolabeled drug analogues in vivo for the development and evaluation of drugs used in cancer therapy.