The invention relates to a method for setting at least one safety relevant parameter of a microprocessor controlled medical apparatus, whereby processes (50) of the medical apparatus are operated based at least on said parameter setting and the medical apparatus comprises a software component (20) driving a user interface (21) connected to a screen (10), and the medical apparatus further comprises means for manual selection and amendment of the parameter setting by an operator. The method comprises displaying by means of the user interface (21) the at least one safety relevant parameter in an input window (11) on the screen (10) and adjusting said parameter in the input window (11) upon manual selection by an operator. In addition, the new parameter is represented in a screen image by means of a video RAM (14). Data regarding the new parameter is then communicated from the user interface (21) to a control unit (30) and to a supervisor unit (40) of the medical apparatus after a parameter setting acceptance operation is actuated by the operator, and the screen image is captured from the video RAM (14) and decoded to data regarding the new parameter. This decoded data regarding the new parameter is communicated to the supervisor unit (40), and the data regarding the new parameter communicated from the user interface (21) is compared with the data regarding the new parameter communicated from the video RAM (14), wherein the result of the comparison leads to:- generating a signal, if the data regarding the new parameter communicated from the user interface (21) differs from the data regarding the new parameter communicated from the video RAM (14), or if data regarding the new parameter communicated from the video RAM (40) did not arrive within a time-out at the supervisor unit (40) after the parameter setting acceptance operation or- controlling processes (50) of the medical apparatus by means of the control unit (30) at least based on the data regarding the new paramete
