Background. The purpose of this study was to generate right ventricular (RV) pressure-volume loops (PVLs) from time-activity curves obtained by first-pass radionuclide angiography (RNA) and RV pressures obtained by right heart catheterization. Methods and Results. Short-lived tantalum 178 was used to obtain first-pass RNA at baseline (n = 31), after nitroglycerin (n = 5), or after the conclusion of cardiac catheterization (n = 13). From the radionuclide-derived RV ejection fraction and thermodilution stroke volume, the RV end-diastolic volume and end-systolic volume were measured. Special proprietary software was developed and used to integrate the pressure and the RNA data. The mean heart rate was 80 ± 17 beats/min; RV ejection fraction, 39% ± 12%; RV end-diastolic volume, 217 ± 79 mL; RV end-systolic volume, 142 ± 74 mL; and RV end-diastolic pressure, 10 ± 7 mm Hg. The RV PVLs were of high quality and reproducible. Conclusions. This study provides proof of concept of the feasibility of generating RV PVL; the short half-life (10 minutes) and low energy (59 keV) of Ta-178 allow the generation of multiple loops at low radiation exposure. Such studies could be performed at the bedside and provide a wealth of information that may have clinical and research merits. Copyright © 2005 by the American Society of Nuclear Cardiology.