A method for adjusting a medical device is provided. The method includes obtaining an initial trajectory of a component of the medical device. The initial trajectory of the component includes a plurality of initial positions. For each of the plurality of initial positions, the method further includes determining whether a collision is likely to occur between a subject and the component according to the initial trajectory of the component. In response to the determination that the collision is likely to occur, the method further includes updating the initial trajectory of the component to determine an updated trajectory of the component.