1. A method for monitoring a radiation dose applied to a patient being exposed or having been exposed to radiation of a medical imaging system, the medical imaging system comprising an X-ray source, the X-ray source describing a trajectory in a coordinate system of reference of the medical imaging system having a first origin, the method comprising: determining angle coordinates of a current region in the coordinate system of reference of the medical imaging system having the first origin, wherein the current region comprises a region of an envelope of a patient model currently exposed or having been exposed to radiation of the X-ray source in relation to a current position of the X-ray source; determining angle coordinates of the current position of the X-ray source in the coordinate system of reference of the medical imaging system having the first origin; determining a difference between the angle coordinates of the current region and the angle coordinates of the current position of the X-ray source in the coordinate system of reference of the medical imaging system having the first origin; determining angle coordinates of the current region in a current coordinate system of reference having a second origin corresponding to the current position of X-ray source; projecting the angle coordinates of the current region in the current coordinate system of reference having the second origin; and displaying a representation of the current region centered on the current coordinate system of reference.