Hunter Stephens, PhD, is an Associate Director in the Pharmacometrics group at Certara. He specializes in applying mathematical and computational models to understand the pharmacokinetics and pharmacodynamics of drugs, especially radiopharmaceuticals. He has a PhD in Medical Physics from Duke University. He also holds an MS in Physics from North Carolina State University and a BS in Mathematics from Tennessee Tech University. His work in TRT has focused on building semi-mechanistic population PK models to simulate and predict absorbed and biologically effective doses to inform dose-range finding and questions of safety and efficacy. In addition, he has extensive experience in radiation dosimetry from external and internal sources.