The invention concerns an x-ray imaging sensor and an x-ray imaging method in which, in a scintillator element (11, 21) or in an element having a corresponding functionality, x-ray quanta are converted into photons having a wavelength substantially greater than the wavelength range of the x-ray quanta. The information detected in the scintillator element (11, 12) is converted to pixel-specific electric signals in a semiconductor element (13, 23), which includes photodiodes (15, 25, 35) or corresponding means that are arranged to divide at least part of the area of the sensor to pixels (14, 24, 34). Arranged in functional connection with the pixel-specific photodiodes (25, 35) or corresponding means, there has been arranged means comprising an I/F (current to frequency) converter (26, 36) or a corresponding component for quantizing the electric signals by converting them to pixel-specific frequencies, i.e. pulse trains.