Reentrant ventricular tachycardia is the next emerging frontier in electrophysiology. Current ablation strategies rely on endocardial voltage measurements to identify myocardial scar and guide catheter ablation procedures. However, this voltage mapping approach has several inherent limitations. In patients with structural heart disease, positron emission tomography (PET)/CT has the potential to provide supplementary scar characterization by displaying additional metabolic (by PET) and morphologic (by CT) tissue-specific information. Three-dimensional scar maps can be created from the imaging datasets, which are uploaded into clinical mapping systems, and can facilitate substrate-guided ablation procedures. This has the potential to shorten procedure times, decrease complications, and improve the procedural success.