Objective: To explore the net power and net energy of a cooled antenna radiator in ex vivo and in vivo porcine livers.Methods: All animal experiments complied with the guidelines of our animal use committee.Microwave ablation (MWA) was performed in porcine livers ex vivo and in vivo with a cooledshaft antenna in different microwave ablation parameter groups(50, 80, and 110 W for 10 min).The energy losses from the microwave antenna or cables were calculated, and the net power,net energy, and the relationship between net power and power readout were determined.