The unit (1) according to the invention is intended for the irradiation of the object by the therapeutic beam (2) of particles from the external source (3) along with the concurrent CT scanning of the object using at least one scanning pair consisting of the source (4) of the scanning ionizing radiation and of the imaging detector (5) arranged on the opposite side. The unit is intended for radiotherapeutic preclinical studies on animals inside the existing radiotherapy vaults. The unit comprises the mobile platform (6) equipped with the adjustable table (7) and with a load-bearing means supporting a scanning pair with movable installation as to the adjustable table (7), where the load-bearing means, scanning pair and adjustable table (7) delimit the free working space (8) for unshielded travel of the therapeutic beam (2) of particles through the unit (1).
