Described is a process for performing radiotherapy treatment according to the invention comprising the following operations: S.1) providing a radiotherapy system (1) comprising a radiation head (3), a movement system (7), a diagnostics subsystem for images, in turn comprising a probe (13) and a position detection subsystem (11)； S.2) by means of the at least one probe (13) acquiring a plurality of images (IM_1, IM_2, IMJ, IM_N) of internal sections of a body to be treated (P)； S.3) by means of the position detection subsystem (11) detecting the position in space of the probe (13) whilst it acquires each of said images (IMJ, IMJ, IMJ, IM _ N)； S.4) on the basis of said images (IMJ, IMJ, IMJ, IM_N) and by means of the movement system (7) moving the radiation head (3) and performing a predetermined treatment on the body to be treated (P).
