Therapeutical apparatus of extracorporeal type

A method for focusing a shock wave generated by a shock wave generator having a nominal focal point upon a target within a patient and being adjustable over a range of focal points, said nominal focal point being located in the middle of said range, said method comprising the steps of:

• adjusting, with the aid of a human operator, the initial position of said shock wave generator relative to a patient to be treated, so that said shock wave generator is positioned at a location at which said nominal focal point coincides with the initial position of a target within said patient;
• automatically tracking the subsequent movement of said target from said nominal focal point and generating an output signal indicative of said subsequent movement of said target;
• and
• automatically adjusting the effective focal point of said shock wave generator as a function of said output signal to cause said effective focal point of said shock wave generator to coincide with said actual location of said target.