A scanning mechanism of a PET device comprises a rotary scanning gantry (100) and a plurality of groups of detector units (200), wherein the scanning gantry (100) comprises a support mechanism (120), a position limiting mechanism, a cage-type frame mechanism (130) positioned therebetween, and at least one driving member (170) the cage-type frame mechanism (130) comprises two groups of module mounting plates (131) arranged oppositely and a plurality of groups of suspension brackets (132) one of the module mounting plates (131) is firmly connected with the support mechanism (120), and the other is firmly connected with the position limiting mechanism the suspension brackets (132) are arranged on the outer edges of the two groups of module mounting plates (131), and are connected firmly with the two groups of module mounting plates (131), respectively the driving member (170) is arranged between a back plate bracket (121) and the module mounting plate (131) on the same side and comprises a connecting plate (171) and a support plate (172) the support plate (172) is an annular plate arranged parallelly to the axial direction an annular cylinder on each module mounting plate (131) is sleeved within the corresponding support plate (172), so that the cage-type frame mechanism (130) rotates frictionally along the annular surfaces of the support plates (172) the detector units (200) are field detachable and can be mounted and dismounted conveniently and quickly by means of the cooperation of the detector units (200) and the scanning gantry (100).La présente invention concerne un mécanisme de balayage dun dispositif de tomographie par émission de positons (TEP) comprenant un cadre tomographique rotatif (100) et une pluralité de groupes dunités détectrices (200), ledit cadre tomographique (100) comprenant un mécanisme de support (120), un mécanisme de limitation de position, un mécanisme cadre de type cage (130) positionné entre ceux-ci, et au moins un élément dentraînement (17
