A medical X-ray apparatus is provided with image detector elements 30 which are arranged in a matrix of rows and columns. In order to improve the noise behaviour of the read amplifiers 46 during the reading per row, a plurality of column conductors 36 is provided per column so that the read time is prolonged in proportion to the number of column conductors and the stray capacitance is reduced proportionally. Both steps reduce the noise in known manner. In the case of an integrated implementation, the conductors for driving the reading per row cannot be arranged arbitrarily close to one another because of their mutual capacitance, so that these conductors require a comparatively large surface area. In order to make a smaller surface area suffice for these conductors, according to the invention each read driver 42 is connected to at least two rows of image detector elements 30 which are not associated with the same column conductor, the number of rows thus connected to one read driver being at the most equal to the number of groups of image detector elements in one column.