Abstract: An apparatus for treatment of signals obtained from photomultiplier tubes, in particular for carrying out a PET, by at least one couple of scintillators associated to photomultiplier tubes (100, 200). For each head (100) of sensors, a relative phototube (3) generates current pulses that are weighed by two resistive chains (6), each of which generates two output currents, and respectively X?A, X?B for the first chain and Y?A, Y?B for the second chain. The phototube (3) generates also a synchronization signal (S?), or last dynode signal, that serves as signals synchronism indicator for a coincidence comparation with signals coming from the other phototube of a paired head (200). The current pulses are transformed into voltage pulses and processed by correcting circuits (40, 41, 42 and 43), obtaining respective transformed signals XA, XB, and YA, YB, whereas the last dynode signals S? are amplified at S by a amplifying block (44).