A method for medical treatment includes beginning coagulating patient tissue using an energy-based clamp coagulator, determining the clamping force, and measuring the acoustic impedance of the patient tissue. The method also includes compensating the measured acoustic impedance for clamp pressure and monitoring the coagulation using at least the compensated measured acoustic impedance. A first medical treatment system includes an energy-based clamp coagulator, an acoustic-impedance measurer, and a force measurer. A second system includes an energy-based clamp coagulator having a clamping member which includes, or is adapted to function as, an electrical-impedance-measuring electrode for measuring an electrical impedance of the clamped patient tissue. A third system includes an energy-based clamp coagulator having a clamping member which includes, or is adapted to function as, a temperature sensor for measuring a temperature of the clamped patient tissue.
