The works on interstitial hyperthermia solved the forward problem until now, Namely, tile SAR curves of circular arrays of radiators, whose currents had uniform phase shifts were studied. On tile other bond, SAR curves of circular arrays, whose members were axially shifted were also studied. In this paper the inverse problem is solved. A certain point, which may be inside or outside tile array is chosen as the target point. For tile target, tile phases of the antenna currents art: determined to maximize the total field. Also the most suitable axial shift or the radiators is also determined. It is round that, higher field concentrations can be achieved with higher operation frequencies. The maximal increase of SAR obtained is 17 dB.