With the advancement of medical technology, there are currently three types of beam limiters that have been put into use, namely manual beam limiters, electric x ray collimator , and automatic beam limiters. Whether it is manual, electric or automatic, it is used to control the closing of the lead leaf in the beam limiter, that is, to control the size of the light field. The instrument panel of the manual beam limiter is on the x ray collimator , and the turning knob of the person controls the opening degree of the lead leaf, that is, the size of the irradiation field. The electric x ray collimator is integrated into the console, and the data is controlled by the person watching the console, and the size of the field is electrically controlled.
The automatic x ray collimator has a state detecting device for the lead leaf inside, and the function of the automatic x ray collimator has the function of automatically adjusting the size of the irradiation field as the focal length of the focus is changed.