A CT device, comprising a frame (1), a CT turntable (2), a CT rotating shaft (3), a cable (5), and a limiting mechanism； the limiting mechanism comprises a driving part (9) and a linear motion part (10), wherein the driving part (9) is provided with a driver (91), a first timing pulley (93) and a transmission shaft (92), the driver (91) is connected to the transmission shaft (92), the first timing pulley (93) is fixed on the transmission shaft (92), and the first timing pulley (93) is connected to the CT rotating shaft (3) by means of a first conveyor belt (8)； the linear motion part (10) is provided with a third timing pulley (103), a ball screw (102), a slider (104) and limit switches (106, 107), the third timing pulley (103) is provided on the ball screw (102) and cooperates with the transmission shaft (92), the slider (104) is provided on the ball screw (102) and cooperates with the ball screw (102), and the slider (104) simultaneously cooperates with the limit switches (106, 107). Motion conversion is performed by a transmission mechanism, and the rotary motion of the CT turntable (2) is converted into linear motion without a repeated motion area； the limiting of the rotary motion of the CT turntable (2) is achieved by means of limiting a linear motion mechanism, thus the problem of limiting the CT turntable (2) is solved by using a simple mechanism, while costs are extremely low.L'invention concerne un dispositif de tomodensitométrie, comprenant un cadre (1), une table tournante CT (2), un arbre rotatif CT (3), un câble (5) et un mécanisme de limitation； le mécanisme de limitation comprend une partie entraînement (9) et une partie mouvement linéaire (10), la partie entraînement (9) est pourvue d'un dispositif d'entraînement (91), d'une première poulie de synchronisation (93) et d'un arbre de transmission (92), le dispositif d'entraînement (91) est relié à l'arbre de transmission (92), la première poulie de synchronisation (93) est fixée sur l'arbre de transmis
